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Sample records for states coulomb excitations

  1. Coulomb excitation

    International Nuclear Information System (INIS)

    McGowan, F.K.; Stelson, P.H.

    1974-01-01

    The theory of Coulomb excitation and a brief review of pertinent treatments of the Coulomb excitation process that are useful for the analysis of experiments are given. Examples demonstrating the scope of nuclear structure information obtainable from gamma spectroscopy are presented. Direct Elambda excitation of 232 Th is discussed in terms of the one phonon octupole vibrational spectrum. B(MI) reduced transition probabilities resulting from Coulomb excitation of odd-A deformed nuclei with heavy ions are presented as a test of the rotational model. The use of gamma ray coincidence and particle-gamma coincidence as tools for investigating Coulomb excitation is discussed. (U.S.)

  2. Coulomb excitation of radioactive 20, 21Na

    Science.gov (United States)

    Schumaker, M. A.; Cline, D.; Hackman, G.; Pearson, C.; Svensson, C. E.; Wu, C. Y.; Andreyev, A.; Austin, R. A. E.; Ball, G. C.; Bandyopadhyay, D.; Becker, J. A.; Boston, A. J.; Boston, H. C.; Buchmann, L.; Churchman, R.; Cifarelli, F.; Cooper, R. J.; Cross, D. S.; Dashdorj, D.; Demand, G. A.; Dimmock, M. R.; Drake, T. E.; Finlay, P.; Gallant, A. T.; Garrett, P. E.; Green, K. L.; Grint, A. N.; Grinyer, G. F.; Harkness, L. J.; Hayes, A. B.; Kanungo, R.; Lisetskiy, A. F.; Leach, K. G.; Lee, G.; Maharaj, R.; Martin, J.-P.; Moisan, F.; Morton, A. C.; Mythili, S.; Nelson, L.; Newman, O.; Nolan, P. J.; Orce, J. N.; Padilla-Rodal, E.; Phillips, A. A.; Porter-Peden, M.; Ressler, J. J.; Roy, R.; Ruiz, C.; Sarazin, F.; Scraggs, D. P.; Waddington, J. C.; Wan, J. M.; Whitbeck, A.; Williams, S. J.; Wong, J.

    2009-12-01

    The low-energy structures of the radioactive nuclei 20, 21Na have been examined using Coulomb excitation at the TRIUMF-ISAC radioactive ion beam facility. Beams of ˜ 5×106 ions/s were accelerated to 1.7MeV/A and Coulomb excited in a 0.5mg/cm^2 natTi target. Two TIGRESS HPGe clover detectors perpendicular to the beam axis were used for γ -ray detection, while scattered nuclei were observed by the Si detector BAMBINO. For 21Na , Coulomb excitation from the 3/2+ ground state to the first excited 5/2+ state was observed, while for 20Na , Coulomb excitation was observed from the 2+ ground state to the first excited 3+ and 4+ states. For both beams, B ( λ L) values were determined using the 2+ rightarrow 0+ de-excitation in 48Ti as a reference. The resulting B( E2) ↓ value for 21Na is 137±9 e^2fm^4, while the resulting B( λ L) ↓ values for 20Na are 55±6 e^2fm^4 for the 3+ rightarrow 2+ , 35.7±5.7 e^2 fm^4 for the 4+ rightarrow 2+ , and 0.154±0.030 μ_ N^2 for the 4+ rightarrow 3+ transitions. This analysis significantly improves the measurement of the 21Na B( E2) value, and provides the first experimental determination of B( λ L) values for the proton dripline nucleus 20Na .-1

  3. The structure of low-lying states in ${}^{140}$Sm studied by Coulomb excitation

    CERN Document Server

    Klintefjord, M.; Görgen, A.; Bauer, C.; Bello Garrote, F.L.; Bönig, S.; Bounthong, B.; Damyanova, A.; Delaroche, J.P.; Fedosseev, V.; Fink, D.A.; Giacoppo, F.; Girod, M.; Hoff, P.; Imai, N.; Korten, W.; Larsen, A.C.; Libert, J.; Lutter, R.; Marsh, B.A.; Molkanov, P.L.; Naïdja, H.; Napiorkowski, P.; Nowacki, F.; Pakarinen, J.; Rapisarda, E.; Reiter, P.; Renstrøm, T.; Rothe, S.; Seliverstov, M.D.; Siebeck, B.; Siem, S.; Srebrny, J.; Stora, T.; Thöle, P.; Tornyi, T.G.; Tveten, G.M.; Van Duppen, P.; Vermeulen, M.J.; Voulot, D.; Warr, N.; Wenander, F.; De Witte, H.; Zielińska, M.

    2016-05-02

    The electromagnetic structure of $^{140}$Sm was studied in a low-energy Coulomb excitation experiment with a radioactive ion beam from the REX-ISOLDE facility at CERN. The $2^+$ and $4^+$ states of the ground-state band and a second $2^+$ state were populated by multi-step excitation. The analysis of the differential Coulomb excitation cross sections yielded reduced transition probabilities between all observed states and the spectroscopic quadrupole moment for the $2_1^+$ state. The experimental results are compared to large-scale shell model calculations and beyond-mean-field calculations based on the Gogny D1S interaction with a five-dimensional collective Hamiltonian formalism. Simpler geometric and algebraic models are also employed to interpret the experimental data. The results indicate that $^{140}$Sm shows considerable $\\gamma$ softness, but in contrast to earlier speculation no signs of shape coexistence at low excitation energy. This work sheds more light on the onset of deformation and collectivit...

  4. Coulomb excitation of 189Os

    International Nuclear Information System (INIS)

    Brandao, S.B.

    1987-01-01

    The level structure of 189 Os has been studied by Coulomb excitation using 35 Cl, 28 Si, 16 O beams. GOSIA, a code written to analyze multiple Coulomb excitation, was used to obtain the reduced probabilities of transition B(E2). The results for interband and intraband turned out possible the classification of the states following Nilsson levels. Gamma-rays originating from deexcitation of 216.7 and 219.4 keV have been separated and the reduced probability of transition has been measured. (A.C.A.S.) [pt

  5. On some aspects of Coulomb excitation of nuclear rotational states

    International Nuclear Information System (INIS)

    Massmann, H.; Robotham, H.

    1979-01-01

    The Coulomb excitation of nuclear rotational states is studied with a semiclassical method using classical trajectories and the classical action in order to construct the excitation probabilities. This method allows one to consider the effect on the excitation probabilities of a weak nuclear potential. An explicit expression for the 'safe bombarding energy' that is the largest bombarding energy for which the nuclear force can be neglected, is found. Also the transfer of angular momentum to the projectile's orbit is considered. One finds that the dynamical distortion of the orbit has a measurable effect on the excitation probabilities for the case of very heavy ions. Furthermore, new dimensionless parameters measuring the dynamical distortion and the effect of the adiabaticity of the collision are introduced and discussed. (author)

  6. Coulomb excitation of rotational states in the 162Dy nucleus in the framework of the generalized semiclassical approximation

    International Nuclear Information System (INIS)

    Bolotin, Yu.L.; Gonchar, V.Yu.; Chekanov, N.A.

    1985-01-01

    Coulomb excitation of rotational states induced in heavyion collisions is treated in the framework of the generalized semiclassical approximation. The Hamiltonian of the system under consideration involves not only Coulomb forces (monopole, quadrupole, and hexadecapole) but as well a real nuclear potential in the form of the deformed Woods-Saxon potential. Strong dependence of the excitation probability on the interference between the Coulomb and nuclear interactions is shown. Calculations are carried out for the reaction 40 Ar+ 162 Dy at E=148.6 MeV. The calculated Coulomb excitation probabilities agree satisfactory with the corresponding experimental values

  7. Lifetime and g-factor measurements of excited states using Coulomb excitation and alpha transfer reactions

    Energy Technology Data Exchange (ETDEWEB)

    Guevara, Z. E., E-mail: zjguevaram@unal.edu.co; Torres, D. A., E-mail: datorresg@unal.edu.co [Physics Department, Universidad Nacional de Colombia, Bogotá D.C. (Colombia)

    2016-07-07

    In this contribution the challenges in the use of a setup to simultaneously measure lifetimes and g-factor values will be presented. The simultaneous use of the transient field technique and the Doppler Shift Attenuation Method, to measure magnetic moments and lifetimes respectively, allows to obtain a complete characterization of the currents of nucleons and the deformation in excited states close to the ground state. The technique is at the moment limited to Coulomb excitation and alpha-transfer reactions, what opens an interesting perspective to consider this type of experiments with radioactive beams. The use of deep-inelastic and fusion-evaporation reactions will be discussed. An example of a setup that makes use of a beam of {sup 106}Cd to study excited states of {sup 110}Sn and the beam nuclei itself will be presented.

  8. Coulomb excitation of neutron-rich odd-$A$ Cd isotopes

    CERN Multimedia

    Reiter, P; Kruecken, R; Gernhaeuser, R A; Kroell, T; Leske, J; Marginean, N M

    We propose to study excited states in the odd-${A}$ isotopes $^{123,125,127}$Cd by ${\\gamma}$-ray spectroscopy following "safe" Coulomb excitation. The experiment aims to determine the B(E2) values connecting excited states with the ground state as well as the long-lived (11/2$^{-}$) isomer. The proposed study profits from the unique capability of ISOLDE to produce beams containing Cd in the ground state or in the isomeric state. Our recent results on the neutron-rich even-A Cd nuclei appear to show that these nuclei may possess some collectivity beyond that calculated by modern shell-model predictions. Beyond-mean-field calculations also predict these nuclei to be weakly deformed. These facets are surprising considering their proximity to the doubly magic $^{132}$Sn. Coulomb-excitation studies of odd-${A}$ Cd isotopes may give a unique insight into the deformation-driving roles played by different orbits in this region. Such studies of the onset of collectivity become especially important in light of recent...

  9. Coulomb excitation of radioactive {sup 79}Pb

    Energy Technology Data Exchange (ETDEWEB)

    Lister, C.J.; Blumenthal, D.; Davids, C.N. [and others

    1995-08-01

    The technical challenges expected in experiments with radioactive beams can already be explored by using ions produced in primary reactions. In addition, the re-excitation of these ions by Coulomb excitation allows a sensitive search for collective states that are well above the yrast line. We are building an experiment to study Coulomb excitation of radioactive ions which are separated from beam particles by the Fragment Mass Analyzer. An array of gamma detectors will be mounted at the focal plane to measure the gamma radiation following re-excitation. Five Compton-suppressed Ge detectors and five planar LEPS detectors will be used. The optimum experiment of this type appears to be the study of {sup 79}Rb following the {sup 24}Mg ({sup 58}Ni,3p) reaction. We calculate that about 5 x 10{sup 5} {sup 79}Rb nuclei/second will reach the excitation foil. This rubidium isotope was selected for study as it is strongly produced and is highly deformed, so easily re-excited. The use of a {sup 58}Ni re-excitation foil offers the best yields. After re-excitation the ions will be subsequently transported into a shielded beamdump to prevent the accumulation of activity.

  10. Excitation and ionization of hydrogen and helium atoms by femtosecond laser pulses: theoretical approach by Coulomb-Volkov states

    International Nuclear Information System (INIS)

    Guichard, R.

    2007-12-01

    We present a theoretical approach using Coulomb-Volkov states that appears useful for the study of atomic multi-photonic processes induced by intense XUV femtosecond laser pulses. It predicts hydrogen ionization spectra when it is irradiated by laser pulses in perturbations conditions. Three ways have been investigated. Extension to strong fields when ℎω > I p : it requires to include the hydrogen ground state population, introducing it in standard Coulomb-Volkov amplitude leads to saturated multi-photonic ionization. Extension to multi-photonic transitions with ℎω p : new quantum paths are open by the possibility to excite the lower hydrogen bound states. Multiphoton excitation of these states is investigated using a Coulomb-Volkov approach. Extension to helium: two-photon double ionization study shows the influence of electronic correlations in both ground and final state. Huge quantity of information such as angular and energetic distributions as well as total cross sections is available. (author)

  11. Coulomb excitation of the proton-dripline nucleus Na20

    Science.gov (United States)

    Schumaker, M. A.; Cline, D.; Hackman, G.; Pearson, C. J.; Svensson, C. E.; Wu, C. Y.; Andreyev, A.; Austin, R. A. E.; Ball, G. C.; Bandyopadhyay, D.; Becker, J. A.; Boston, A. J.; Boston, H. C.; Buchmann, L.; Churchman, R.; Cifarelli, F.; Cooper, R. J.; Cross, D. S.; Dashdorj, D.; Demand, G. A.; Dimmock, M. R.; Drake, T. E.; Finlay, P.; Gallant, A. T.; Garrett, P. E.; Green, K. L.; Grint, A. N.; Grinyer, G. F.; Harkness, L. J.; Hayes, A. B.; Kanungo, R.; Lisetskiy, A. F.; Leach, K. G.; Lee, G.; Maharaj, R.; Martin, J.-P.; Moisan, F.; Morton, A. C.; Mythili, S.; Nelson, L.; Newman, O.; Nolan, P. J.; Orce, J. N.; Padilla-Rodal, E.; Phillips, A. A.; Porter-Peden, M.; Ressler, J. J.; Roy, R.; Ruiz, C.; Sarazin, F.; Scraggs, D. P.; Waddington, J. C.; Wan, J. M.; Whitbeck, A.; Williams, S. J.; Wong, J.

    2009-10-01

    The low-energy structure of the proton dripline nucleus Na20 has been studied using Coulomb excitation at the TRIUMF-ISAC radioactive ion beam facility. A 1.7-MeV/nucleon Na20 beam of ~5×106 ions/s was Coulomb excited by a 0.5-mg/cm2natTi target. Scattered beam and target particles were detected by the BAMBINO segmented Si detector while γ rays were detected by two TIGRESS HPGe clover detectors set perpendicular to the beam axis. Coulomb excitation from the 2+ ground state to the first excited 3+ and 4+ states was observed, and B(λL) values were determined using the 2+→0+ de-excitation in Ti48 as a reference. The resulting B(λL)↓ values are B(E2;3+→2+)=55±6e2fm4 (17.0±1.9 W.u.), B(E2;4+→2+)=35.7±5.7e2fm4 (11.1±1.8 W.u.), and B(M1;4+→3+)=0.154±0.030μN2 (0.086±0.017 W.u.). These measurements provide the first experimental determination of B(λL) values for this proton dripline nucleus of astrophysical interest.

  12. Exclusion of nuclear forces in heavy-ion Coulomb excitation and Coulomb fission experiments

    International Nuclear Information System (INIS)

    Neese, R.E.; Guidry, M.W.

    1982-01-01

    A simple prescription for estimating the energy at which nuclear forces begin to play a role in heavy-ion Coulomb excitation and Coulomb fission experiments is presented. The method differs from most commonly used recipes in accounting for projectile and target nucleus deformation effects. Using a single adjustable parameter the formula reproduces the energy for the onset of Coulomb-nuclear interference effects for a broad range of heavy-ion systems. It is suggested that most Coulomb fission experiments which have been done involve both Coulomb and nuclear excitation processes and should more properly be termed Coulomb-nuclear fission experiments

  13. No evidence of reduced collectivity in Coulomb-excited Sn isotopes

    Science.gov (United States)

    Kumar, R.; Saxena, M.; Doornenbal, P.; Jhingan, A.; Banerjee, A.; Bhowmik, R. K.; Dutt, S.; Garg, R.; Joshi, C.; Mishra, V.; Napiorkowski, P. J.; Prajapati, S.; Söderström, P.-A.; Kumar, N.; Wollersheim, H.-J.

    2017-11-01

    In a series of Coulomb excitation experiments the first excited 2+ states in semimagic Sn 112 ,116 ,118 ,120 ,122 ,124 isotopes were excited using a 58Ni beam at safe Coulomb energy. The B (E 2 ; 0+→2+) values were determined with high precision (˜3 %) relative to 58Ni projectile excitation. These results disagree with previously reported B (E 2 ↑) values [A. Jungclaus et al., Phys. Lett. B 695, 110 (2011)., 10.1016/j.physletb.2010.11.012] extracted from Doppler-shift attenuation lifetime measurements, whereas the reported mass dependence of B (E 2 ↑) values is very similar to a recent Coulomb excitation study [J. M. Allmond et al., Phys. Rev. C 92, 041303(R) (2015), 10.1103/PhysRevC.92.041303]. The stable Sn isotopes, key nuclei in nuclear structure, show no evidence of reduced collectivity and we, thus, reconfirm the nonsymmetric behavior of reduced transition probabilities with respect to the midshell A =116 .

  14. Characterising excited states in and around the semi-magic nucleus $^{68}$ Ni using Coulomb excitation and one-neutron transfer

    CERN Multimedia

    It is proposed to investigate the structure of excited states in $^{68, 70}$Ni(Z =28, N=40, 42) via the measurement of electromagnetic matrix elements in a Coulomb excitation experiment in order to study the N = 40 harmonic-oscillator shell and the Z = 28 proton shell closures. The measured B(E2) values connecting low-lying 0$^{+}$ and 2$^{+}$ can be compared to shell-model predictions. It is also proposed to perform the one-neutron transfer reaction ${d}$($^{68}$Ni,$^{69}$Ni)${p}$, with the aim of populating excited states in $^{69}$Ni. Comparisons with the states populated in the recently performed ${d}$($^{66}$Ni,$^{67}$Ni)${p}$ reaction will be useful in determining the role of the neutron $d_{5/2}$ orbital in the semi-magic properties of $^{68}$Ni.

  15. JANUS - A setup for low-energy Coulomb excitation at ReA3

    Science.gov (United States)

    Lunderberg, E.; Belarge, J.; Bender, P. C.; Bucher, B.; Cline, D.; Elman, B.; Gade, A.; Liddick, S. N.; Longfellow, B.; Prokop, C.; Weisshaar, D.; Wu, C. Y.

    2018-03-01

    A new experimental setup for low-energy Coulomb excitation experiments was constructed in a collaboration between the National Superconducting Cyclotron Laboratory (NSCL), Lawrence Livermore National Laboratory (LLNL), and the University of Rochester and was commissioned at the general purpose beam line of NSCL's ReA3 reaccelerator facility. The so-called JANUS setup combines γ-ray detection with the Segmented Ge Array (SeGA) and scattered particle detection using a pair of segmented double-sided Si detectors (Bambino 2). The low-energy Coulomb excitation program that JANUS enables will complement intermediate-energy Coulomb excitation studies that have long been performed at NSCL by providing access to observables that quantify collectivity beyond the first excited state, including the sign and magnitude of excited-state quadrupole moments. In this work, the setup and its performance will be described based on the commissioning run that used stable 78Kr impinging onto a 1.09 mg/cm2208Pb target at a beam energy of 3.9 MeV/u.

  16. Coulomb Excitation of Neutron Deficient Sn-Isotopes using REX-ISOLDE

    CERN Multimedia

    Di julio, D D; Kownacki, J M; Marechal, F; Andreoiu, C; Siem, S; Perrot, F; Van duppen, P L E; Napiorkowski, P J; Iwanicki, J S

    2002-01-01

    It is proposed to study the evolution of the reduced transition probabilities, B(E2; 0$^{+} \\rightarrow$ 2$^{+}$), for neutron deficient Sn isotopes by Coulomb excitation in inverse kinematics using REX-ISOLDE and the MINIBALL detector array. Measurements of the reduced transition matrix element for the transition between the ground state and the first excited 2$^{+}$ state in light even-even Sn isotopes provide a means to study e.g. core polarization effects in the $^{100}$Sn core. Previous attempts to measure this quantity have been carried out using the decay of isomeric states populated in fusion evaporation reactions. We thus propose to utilize the unique opportunity provided by REX-ISOLDE, after the energy upgrade to 3.1 MeV/u, to use the more model-independent approach of Coulomb excitation to measure this quantity in a number of isotopes in this region.

  17. Coulomb excitation of {sup 8}Li

    Energy Technology Data Exchange (ETDEWEB)

    Assuncao, Marlete; Britos, Tatiane Nassar [Universidade Federal de Sao Paulo (UNIFESP), SP (Brazil). Dept. de Ciencias Exatas e da Terra; Descouvemont, Pierre [Universite Libre de Bruxelles (ULB), Brussels (Belgium). Physique Nucleaire Theorique et Physique Mathematique; Lepine-Szily, Alinka; Lichtenthaler Filho, Rubens; Barioni, Adriana; Silva, Diego Medeiros da; Pereira, Dirceu; Mendes Junior, Djalma Rosa; Pires, Kelly Cristina Cezaretto; Gasques, Leandro Romero; Morais, Maria Carmen; Added, Nemitala; Neto Faria, Pedro; Rec, Rafael [Universidade de Sao Paulo (IF/USP), SP (Brazil). Inst. de Fisica. Dept. de Fisica Nuclear

    2012-07-01

    Full text: This work shows the Coulomb Excitation of {sup 8}Li on targets that have effectively behavior of Rutherford in angles and energies of interest for determining the value of the B(E2) electromagnetic transition. Theoretical aspects involved in this type of measure, known as COULEX [1], and some results in the literature [2-3] will be presented. Some problems with the targets and measurement system while performing an experiment on Coulomb Excitation of {sup 8}Li will be discussed: the energy resolution, background, possible contributions of the primary beam and also the excited states of the target near the region of elastic and inelastic peaks. They will be illustrated by measurements of the Coulomb Excitation of {sup 8}Li on targets of {sup 197}Au and {sup 208}Pb using the system RIBRAS(Brazilian Radioactive Ion Beam). In this case, the {sup 8}Li beam(T{sub 1/2} = 838 ms)is produced by {sup 9}Be({sup 7}Li;{sup 8} Li){sup 8}Be reaction from RIBRAS system which is installed at Instituto de Fisica of the Universidade de Sao Paulo. The primary {sup 7L}i beam is provided by Pelletron Accelerator. [1] K. Alder and A. Winther, Electromagnetic Excitation, North-Holland, New York, 1975; [2] P. Descouvemont and D. Baye, Phys. Letts. B 292, 235-238, 1992; [3] J. A. Brown, F. D. Becchetti, J. W. Jaenecke, K, Ashktorab, and D. A. Roberts, J. J. Kolata, R. J. Smith, and K. Lamkin, R. E. Warner, Phys. Rev. Letts., 66, 19, 1991; [4] R. J. Smith, J. J Kolata, K. Lamkin and A. Morsard, F. D. Becchetti, J. A. Brown, W. Z. Liu, J. W. Jaenecke, and D. A. Roberts, R. E. Warner, Phys. Rev. C, 43, 5, 1991. (author)

  18. Relativistic Coulomb excitation

    International Nuclear Information System (INIS)

    Winther, A.; Alder, K.

    1979-01-01

    Coulomb excitation of both target and projectile in relativistic heavy ion collisions is evaluated including the lowest order correction for the deviation from a straight line trajectory. Explicit results for differential and total cross sections are given in the form of tables and figures. (Auth.)

  19. Coulomb excitations of low lying levels in 127I and 197Au

    International Nuclear Information System (INIS)

    Singh, K.P.; Tayal, D.C.; Hans, H.S.

    1988-01-01

    The low-lying levels of 127 I and 197 Au were Coulomb excited with 3.54 to 4.2 MeV protons. The reduced quadrupole transition probabilities of the 203, 374.9, 418, 618.4, 628.7, 651.1 and 745.5 keV states of 127 I, and the 268.8, 278.9, 502, and 547.5 keV states of 197 Au was measured from Coulomb excitation by observing the de-excitation gamma rays with a high resolution Ge(Li) detector. The low-energy protons were used for the first time to Coulomb-excite the two levels at 618.4 and 651.1 keV of 127 I and one level at 502 keV of 197 Au. The present experimental results are found in agreement with the existing experimental data except the B(E2) value of the level at 268.8 keV of 197 Au. (author). 4 figs., 4 tabs., 32 refs

  20. Electromagnetic excitation with very heavy ions at and above the Coulomb barrier

    International Nuclear Information System (INIS)

    Wollersheim, H.J.

    1988-08-01

    The present report is part of a systematic study of the electromagnetic properties of strongly deformed and shape transitional nuclei carried out at GSI. The high efficiency particle-gamma detector system is described to perform multiple Coulomb excitation experiments with very heavy projectiles. Some results obtained for the shape transitional nucleus 196 Pt will be presented to exemplify the importance of having access to both the level energies and the E2-transition matrix elements when discussing the possible structure of these states. The second part of this paper is devoted to transfer reactions between very heavy nuclei. In contrast to light projectiles heavy ions offer the possibility to study new phenomena which originate in the much larger Coulomb contribution to the total interaction. In particular, heavy deformed nuclei will be Coulomb excited by the strong electromagnetic field to high spin states already at the time when they start interacting through the nuclear forces. The particle transfer therefore takes place mainly between excited collective states and thus should give information about the interplay between single-particle degrees of freedom, pair correlations and collective excitations. In this paper results of experiments will be reported in which nuclei from the rare earth and the actinide region have been bombarded by 206,208 Pb projectiles at incident energies near the Coulomb barrier. (orig./HSI)

  1. Excitation and ionization of hydrogen and helium atoms by femtosecond laser pulses: theoretical approach by Coulomb-Volkov states; Excitation et ionisation des atomes d'hydrogene et d'helium par des impulsions laser femtosecondes: approche theorique par des etats de Coulomb-Volkov

    Energy Technology Data Exchange (ETDEWEB)

    Guichard, R

    2007-12-15

    We present a theoretical approach using Coulomb-Volkov states that appears useful for the study of atomic multi-photonic processes induced by intense XUV femtosecond laser pulses. It predicts hydrogen ionization spectra when it is irradiated by laser pulses in perturbations conditions. Three ways have been investigated. Extension to strong fields when {Dirac_h}{omega} > I{sub p}: it requires to include the hydrogen ground state population, introducing it in standard Coulomb-Volkov amplitude leads to saturated multi-photonic ionization. Extension to multi-photonic transitions with {Dirac_h}{omega} < I{sub p}: new quantum paths are open by the possibility to excite the lower hydrogen bound states. Multiphoton excitation of these states is investigated using a Coulomb-Volkov approach. Extension to helium: two-photon double ionization study shows the influence of electronic correlations in both ground and final state. Huge quantity of information such as angular and energetic distributions as well as total cross sections is available. (author)

  2. Unsafe Coulomb excitation of $^{240-244}Pu$

    CERN Document Server

    Wiedenhöver, I; Hackman, L; Ahmad, I; Greene, J P; Amro, H; Carpenter, M P; Nisius, D T; Reiter, P; Lauritsen, T; Lister, C J; Khoo, T L; Siem, S; Cizewski, J A; Seweryniak, D; Uusitalo, J; Macchiavelli, A O; Chowdhury, P; Seabury, E H; Cline, D; Wu, C Y

    1999-01-01

    The high spin states of /sup 240/Pu and /sup 244/Pu have been investigated with GAMMASPHERE at ATLAS, using Coulomb excitation with a /sup 208/Pb beam at energies above the Coulomb barrier. Data on a transfer channel leading to /sup 242/Pu were obtained as well. In the case of /sup 244/Pu, the yrast band was extended to 34h(cross), revealing the completed pi i/sub 13/2/ alignment, a "first" for actinide nuclei. The yrast sequence of /sup 242/Pu was also extended to higher spin and a similar backbend was delineated. In contrast, while the ground state band of /sup 240/Pu was measured up to the highest rotational frequencies ever reported in the actinide region (~300 keV), no sign of particle alignment was observed. (11 refs).

  3. Coulomb excitation of neutron-rich $^{134-136}$Sn isotopes

    CERN Multimedia

    We propose to study excited states in the isotopes $^{134,136}$Sn by $\\gamma$-ray spectroscopy following "safe" Coulomb excitation. The experiment aims to investigate the evolution of quadrupole collectivity beyond the magic shell closure at N = 82 by the determination of B(E2) values and electric quadrupole moments $\\mathcal{Q}_2$. Recent shell-model calculations using realistic interactions predict possible enhanced collectivity in neutron-rich regions. Evidence for this could be obtained by this experiment. Furthermore, the currently unknown excitation energies of the 2$^+_{1}$ and 4$^+_{1}$ states in $^{136}$Sn will be measured for the first time.

  4. Low-energy Coulomb excitation of neutron-rich zinc isotopes

    CERN Document Server

    Van de Walle, J; Behrens, T; Bildstein, V; Blazhev, A; Cederkäll, J; Clément, E; Cocolios, T E; Davinson, T; Delahaye, P; Eberth, J; Ekström, A; Fedorov, D V; Fedosseev, V; Fraile, L M; Franchoo, S; Gernhäuser, R; Georgiev, G; Habs, D; Heyde, K; Huber, G; Huyse, M; Ibrahim, F; Ivanov, O; Iwanicki, J; Jolie, J; Kester, O; Köster, U; Kröll, T; Krücken, R; Lauer, M; Lisetskiy, A F; Lutter, R; Marsh, B A; Mayet, P; Niedermaier, O; Pantea, M; Raabe, R; Reiter, P; Sawicka, M; Scheit, H; Schrieder, G; Schwalm, D; Seliverstov, M D; Sieber, T; Sletten, G; Smirnova, N; Stanoiu, M; Stefanescu, I; Thomas, J C; Valiente-Dobón, J J; Van Duppen, P; Verney, D; Voulot, D; Warr, N; Weisshaar, D; Wenander, F; Wolf, B H; Zielinska, M

    2009-01-01

    At the radioactive ion beam facility REX-ISOLDE, neutron-rich zinc isotopes were investigated using low-energy Coulomb excitation. These experiments have resulted in B(E2,20) values in 74-80Zn, B(E2,42) values in 74,76Zn and the determination of the energy of the first excited 2 states in 78,80Zn. The zinc isotopes were produced by high-energy proton- (A=74,76,80) and neutron- (A=78) induced fission of 238U, combined with selective laser ionization and mass separation. The isobaric beam was postaccelerated by the REX linear accelerator and Coulomb excitation was induced on a thin secondary target, which was surrounded by the MINIBALL germanium detector array. In this work, it is shown how the selective laser ionization can be used to deal with the considerable isobaric beam contamination and how a reliable normalization of the experiment can be achieved. The results for zinc isotopes and the N=50 isotones are compared to collective model predictions and state-of-the-art large-scale shell-model calculations, i...

  5. Coulomb Excitation of a Neutron-Rich $^{88}$Kr Beam Search for Mixed Symmetry States

    CERN Multimedia

    Andreoiu, C; Napiorkowski, P J; Iwanicki, J S

    2002-01-01

    We propose to use the ISOLDE/REX/MINIBALL/CD set-up to perform a Coulomb Excitation experiment with a $^{88}$Kr radioactive beam. The motivation includes a search for $Mixed$ $Symmetry$ states predicted by the IBM-2 model, gathering more spectroscopy data about the $^{88}$Kr nucleus and extending shape coexistence studies (performed previously by the proposers for neutron-deficient Kr isotopes) to the neutron-rich side. The proposed experiment will provide data complementary to the Coulomb Excitation of a relativistic $^{88}$Kr beam proposed by D. Tonev et al. for a RISING experiment. A total of 12 days of beam time is necessary for the experiment, equally divided into two runs. One run with a 2.2 MeV/A beam energy on a $^{48}$Ti target and a second run with the maximum available REX energy of 3.1 MeV/A on a $^{208}$Pb target are requested. Using either a UC$_{x}$ or ThC$_{x}$ fissioning primary target coupled with a plasma source by a cooled transfer line seems to be the best choice for the proposed experime...

  6. Cold transfer between deformed, Coulomb excited nuclei

    International Nuclear Information System (INIS)

    Bauer, H.

    1998-01-01

    The scattering system 162 Dy → 116 Sn has been examined at energies in the vicinity of the Coulomb barrier using the Heidelberg-Darmstadt Crystal Ball spectrometer combined with 5 Germanium-CLUSTER detectors. In order to study pairing correlations as a function of angular momentum cold events were selected in the 2n stripping channel by identifying and suppressing the dominant hot part of the transfer with the Crystal Ball. The CLUSTER detectors with their high γ-efficiency were used to identify the transfer channel and to resolve individual final states. Cross sections for the population of individual yrast states in a cold transfer reaction have been measured for the first time indicating the strong influence of higher transfer multipolarities. At small surface distances Coulomb-nuclear interferences were found to be responsible for the stronger decline of the population of higher yrast states in the transfer channel as compared to the Coulex channel. As a preparatory study for 2n transfer measurements between high spin yrast states in the backbending region of deformed nuclei the Coulomb excitation process in the crossing region of two bands in 162 Dy has been analyzed. The gross properties of the measured population probabilities could be interpreted in a simple band mixing model. (orig.)

  7. Coulomb excitation of $^{110}$Sn using REX-ISOLDE

    CERN Document Server

    Ekström, A; Hurst, A; Fahlander, C; Banu, A; Butler, P; Eberth, J; Górska, M; Habs, D; Huyse, M; Kester, O; Niedermayer, O; Nilsson, T; Pantea, M; Scheit, H; Schwalm, D; Sletten, G; Ushasi, D P; Van Duppen, P; Warr, N; Weisshaar, D

    2006-01-01

    In this paper, we report the preliminary result from the first Coulomb excitation experiment at REX-ISOLDE (Habs et al 1998 Nucl. Instrum. Methods B 139 128) using neutron-deficient Sn-beams. The motivation of the experiment is to deduce the reduced transition probability, B(E2 ; 2$^+\\rightarrow$ 0$^+$) , for the sequence of neutron deficient, unstable, even-even Sn-isotopes from using a radioactive beam opens up a new path to study the lifetime of the first excited 2$^+$ state in these isotopes. The de-excitation path following fusion-evaporation reactions will for the even-even Sn isotopes pass via an isomeric 6$^+$ state, located at higher energy, which thus hampers measurements of the lifetime of the first excited state using, e.g., recoil-distance methods. For this reason the reduced transition probability of the first excited 2$^+$ state has remained unknown in this chain of isotopes although the B(E2) value of the stable isotope $^{112}$Sn was measured approximately 30 years ago (see, e.g., Stelson et...

  8. Excitation and ionization of hydrogen and helium atoms by femtosecond laser pulses: theoretical approach by Coulomb-Volkov states; Excitation et ionisation des atomes d'hydrogene et d'helium par des impulsions laser femtosecondes: approche theorique par des etats de Coulomb-Volkov

    Energy Technology Data Exchange (ETDEWEB)

    Guichard, R

    2007-12-15

    We present a theoretical approach using Coulomb-Volkov states that appears useful for the study of atomic multi-photonic processes induced by intense XUV femtosecond laser pulses. It predicts hydrogen ionization spectra when it is irradiated by laser pulses in perturbations conditions. Three ways have been investigated. Extension to strong fields when {Dirac_h}{omega} > I{sub p}: it requires to include the hydrogen ground state population, introducing it in standard Coulomb-Volkov amplitude leads to saturated multi-photonic ionization. Extension to multi-photonic transitions with {Dirac_h}{omega} < I{sub p}: new quantum paths are open by the possibility to excite the lower hydrogen bound states. Multiphoton excitation of these states is investigated using a Coulomb-Volkov approach. Extension to helium: two-photon double ionization study shows the influence of electronic correlations in both ground and final state. Huge quantity of information such as angular and energetic distributions as well as total cross sections is available. (author)

  9. Coulomb excitation of the two proton-hole nucleus $^{206}$Hg

    CERN Multimedia

    We propose to use Coulomb excitation of the single magic two-proton-hole nucleus $^{206}$Hg. In a single-step excitation both the first 2$^{+}$ and the highly collective octupole 3$^{-}$ states will be populated. Thus, information on both quadrupole and octupole collectivity will be gained in this neutron-rich nucleus. Due to the high beam intensity, we will be able to observe multi-step Coulomb excitation as well, providing further test on theoretical calculations. The results will be used to improve the predictive power of the shell model for more exotic nuclei as we move to lighter N=126 nuclei. The experiment will use the new HIE-ISOLDE facility and the MINIBALL array, and will take advantage of the recently developed $^{206}$Hg beam from the molten lead target.

  10. The giant-dipole-resonance effect in coulomb excitation of 10B

    International Nuclear Information System (INIS)

    Vermeer, W.J.; Zabel, T.H.; Esat, M.T.; Kuehner, J.A.; Spear, R.H.; Baxter, A.M.

    1982-04-01

    Coulomb excitation of the 0.718-MeV, Jsup(π) = 1 + , first excited state of 10 B has been studied using projectile excitation by 208 Pb and observing the backward scattered particles. The results give a clear indication of the virtual excitation of the giant dipole resonance as a second-order effect. The observed magnitude is consistent with the usual hydrodynamic model estimate and with a recent shell-model calculation

  11. Coulomb excitation of {sup 123}Cd

    Energy Technology Data Exchange (ETDEWEB)

    Hartig, Anna-Lena; Kroell, Thorsten; Ilieva, Stoyanka; Boenig, Sabine; Thuerauf, Michael [IKP, TU Darmstadt (Germany); Simpson, Gary; Drouet, Floriane; Ramdhane, Mourad [LPSC, Grenoble (France); Georgiev, Georgi [CSNSM, Orsay (France); Kesteloot, Nele; Wrzosek-Lipska, Kasia [KU, Leuven (Belgium); Jungclaus, Andrea; Illana Sison, Andres [CSIC, Madrid (Spain); Balabanski, Dimiter [INRNE-BAS, Sofia (Bulgaria); Warr, Nigel [Koeln Univ. (Germany). IKP; Voulot, Didier; Wenander, Fredrik; Marsh, Bruce [CERN, Geneva (Switzerland)

    2013-07-01

    On the neutron-rich side of the valley of stability in the vicinity of the double magic nucleus {sup 132}Sn one can find the {sup 123}Cd isotope. Surprisingly the neutron-rich even-A Cd isotopes in this region are showing signs of collectivity beyond that calculated by modern shell-model predictions. In order to gain a deeper insight in this phenomenon we started to extend these studies to odd-A Cd isotopes. As first isotope the exotic nucleus {sup 123}Cd was produced for safe Coulomb excitation by the ISOLDE facility at CERN and post-accelerated by REX-ISOLDE. The γ-decay from excited states was detected with the MINIBALL array. A report on the status of the ongoing analysis is given.

  12. Coulomb excitation of {sup 107}Sn

    Energy Technology Data Exchange (ETDEWEB)

    DiJulio, D.D.; Cederkall, J.; Fahlander, C. [Lund University, Physics Department, 118, Lund (Sweden); Ekstroem, A. [University of Oslo, Department of Physics and Center of Mathematics for Applications, Oslo (Norway); Hjorth-Jensen, M. [University of Oslo, Department of Physics and Center of Mathematics for Applications, Oslo (Norway); Michigan State University, National Superconducting Cyclotron Laboratory and Department of Physics and Astronomy, East Lansing, MI (United States); Albers, M.; Blazhev, A.; Fransen, C.; Geibel, K.; Hess, H.; Reiter, P.; Seidlitz, M.; Taprogge, J.; Warr, N. [University of Cologne, Institute of Nuclear Physics, Cologne (Germany); Bildstein, V.; Gernhaeuser, R.; Wimmer, K. [Technische Universitaet Muenchen, Physik Department E12, Garching (Germany); Darby, I.; Witte, H. de [Instituut voor Kern- en Stralingsfysica, Leuven (Belgium); Davinson, T. [University of Edinburgh, Department of Physics and Astronomy, Edinburgh (United Kingdom); Diriken, J. [Instituut voor Kern- en Stralingsfysica, Leuven (Belgium); Studiecentrum voor Kernenergie/Centre d' Etude de l' energie Nucleaire (SCK CEN), Mol (Belgium); Goergen, A.; Siem, S.; Tveten, G.M. [University of Oslo, Department of Physics, Oslo (Norway); Iwanicki, J. [University of Warsaw, Heavy Ion Laboratory, Warsaw (Poland); Lutter, R. [Ludwig-Maximilians-Universitaet Muenchen, Fakultaet fuer Physik, Garching (Germany); Scheck, M. [University of Liverpool, Oliver Lodge Laboratory, Liverpool (United Kingdom); Walle, J.V. de [PH Department, Geneva 23 (Switzerland); Voulot, D.; Wenander, F. [AB Department, Geneva 23 (Switzerland)

    2012-07-15

    The radioactive isotope {sup 107}Sn was studied using Coulomb excitation at the REX-ISOLDE facility at CERN. This is the lightest odd-Sn nucleus examined using this technique. The reduced transition probability of the lowest-lying 3/2{sup +} state was measured and is compared to shell-model predictions based on several sets of single-neutron energies relative to {sup 100}Sn. Similar to the transition probabilities for the 2{sup +} states in the neutron-deficient even-even Sn nuclei, the measured value is underestimated by shell-model calculations. Part of the strength may be recovered by considering the ordering of the d{sub 5/2} and g{sub 7/2} single-neutron states. (orig.)

  13. Coulomb excitation of neutron-deficient polonium isotopes studied at ISOLDE

    CERN Document Server

    Neven, Michiel

    The polonium isotopes represent an interesting region of the nuclear chart having only two protons outside the Z = 82 closed shell. These isotopes have already been extensively studied theoretically and experimentally. The heavier isotopes (A > 200) seem to follow a "regular seniority-type regime" while for the lighter isotopes (A < 200) a more collective behavior is observed. Many questions remain regarding the transition between these two regimes and the configuration mixing between quantum states. Experiments in the lighter polonium isotopes point to the presence of shape coexistence, however the phenomenon is not fully understood. A Coulomb excitation study of the polonium isotopes whereby the dynamic properties are investigated can provide helpful insights in understanding the shape coexistence phenomena. In this thesis $^{202}$Po was studied via Coulomb excitation. The $^{202}$Po isotope was part of an experimental campaign in which the $^{196,198,200,206}$Po isotopes were studied as well via Coulomb...

  14. Coulomb excitation of atoms by fast multicharged ions

    International Nuclear Information System (INIS)

    Yudin, G.L.

    1980-01-01

    Investigated is coulomb eXcitation of discrete levels of a hydrogen-like atom by a fast multicharged ion. Obtained are dependences of probabilities of channels 1S→nS and 1S→nP on the sight parameter in the zero order of sudden excitation theory. 1S-2S transition is considered in detail. Carried out are calculations for excitation of the hydrogen atom by the wholy bare carbon atom. It is shown, that at low values of excitation pr.ocess parameter eta excitation probability is a monotonously decreasing function of the impact parameter. With the growth of eta the situation is changed, and at low impact parameters the probability of 1S-2S transition is decreased. At high impact parameters approximation of sudden excitations is unacceptable, here lagging of coulomb interaction is essential

  15. Probing shape coexistence in neutron-deficient $^{72}$Se via low-energy Coulomb excitation

    CERN Multimedia

    We propose to study the evolution of nuclear structure in neutron-­deficient $^{72}$Se by performing a low-­energy Coulomb excitation measurement. Matrix elements will be determined for low-­lying excited states allowing for a full comparison with theoretical predictions. Furthermore, the intrinsic shape of the ground state, and the second 0$^{+}$ state, will be investigated using the quadrupole sum rules method.

  16. Coulomb excitation of the 4+1 states of 194Pt, 196Pt and 198Pt

    International Nuclear Information System (INIS)

    Fewell, M.P.; Gyapong, G.J.; Spear, R.H.

    1987-09-01

    Probabilities for the Coulomb excitation of the 4 1 + states of 194 Pt, 196 Pt, 198 Pt by the backscattering of 4 He, 12 C and 16 O ions are reported. Model-independent values of the matrix elements 1 + ; M(E4), 4 1 + > and 1 + , M(E2), 4 1 + > are extracted. Agreement with previous measurements of these matrix elements is good. Values of β 2 and β 4 are determined for 194 Pt and compared with calculations of these quantities

  17. Coulomb Excitation of the N = 50 nucleus 80Zn

    International Nuclear Information System (INIS)

    Van de Walle, J.; Cocolios, T. E.; Huyse, M.; Ivanov, O.; Mayet, P.; Raabe, R.; Sawicka, M.; Stefanescu, I.; Duppen, P. van; Aksouh, F.; Ames, F.; Habs, D.; Lutter, R.; Behrens, T.; Gernhauser, R.; Kroell, T.; Kruecken, R.; Bildstein, V.; Blazhev, A.; Eberth, J.

    2008-01-01

    Neutron rich Zinc isotopes, including the N = 50 nucleus 80 Zn, were produced and post-accelerated at the Radioactive Ion Beam (RIB) facility REX-ISOLDE (CERN). Low-energy Coulomb excitation was induced on these isotopes after post-acceleration, yielding B(E2) strengths to the first excited 2 + states. For the first time, an excited state in 80 Zn was observed and the 2 1 + state in 78 Zn was established. The measured B(E2,2 1 + →0 1 + ) values are compared to two sets of large scale shell model calculations. Both calculations reproduce the observed B(E2) systematics for the full Zinc isotopic chain. The results for N = 50 isotones indicate a good N = 50 shell closure and a strong Z = 28 proton core polarization. The new results serve as benchmarks to establish theoretical models, predicting the nuclear properties of the doubly magic nucleus 78 Ni

  18. Vibrational motions in rotating nuclei studied by Coulomb excitations

    Energy Technology Data Exchange (ETDEWEB)

    Shimizu, Yoshifumi R [Kyushu Univ., Fukuoka (Japan). Dept. of Physics

    1998-03-01

    As is well-known Coulomb excitation is an excellent tool to study the nuclear collective motions. Especially the vibrational excitations in rotating nuclei, which are rather difficult to access by usual heavy-ion fusion reactions, can be investigated in detail. Combined with the famous 8{pi}-Spectrometer, which was one of the best {gamma}-ray detector and had discovered some of superdeformed bands, such Coulomb excitation experiments had been carried out at Chalk River laboratory just before it`s shutdown of physics division. In this meeting some of the experimental data are presented and compared with the results of theoretical investigations. (author)

  19. Coulomb interaction in atomic and nuclear physics: Inner-Shell excitation, Coulomb dissociation of nuclei, and nuclear polarizability in electronic atoms

    International Nuclear Information System (INIS)

    Hoffmann, B.

    1984-07-01

    In three chapters different physical situations are described which have commonly the Coulomb interaction as driving force. The first two chapters study the Coulomb interactions in connection with the excitation of inner electron shells and the Coulomb excitation of nuclei in first order. In the third part on effect ofthe Coulomb interaction between electronic shell and nucleus is treated in second order (nuclear polarization), and its effect on the isotopic and isomeric shift is studied. (orig./HSI) [de

  20. Coulomb excitation of $^{182-184}$ Hg: Shape coexistence in the neutron-deficient lead region

    CERN Multimedia

    We put forward a study of the interplay between individual nucleon behavior and collective degrees of freedom in the nucleus, as manifested in shape coexistence in the neutron-deficient lead region. As a first step of this experimental campaign, we propose to perform Coulomb excitation on light mercury isotopes to probe their excited states and determine transitional and diagonal E2 matrix elements, especially reducing the current uncertainties. The results from previous Coulomb excitation measurements in this mass region performed with 2.85 MeV/u beams from REX-ISOLDE have shown the feasibility of these experiments. Based on our past experience and the results obtained, we propose a detailed study of the $^{182-184}$Hg nuclei, that exhibit a pronounced mixing between 2 low-lying excited states of apparently different deformation character, using the higher energy beams from HIE-ISOLDE which are crucial to reach our goal. The higher beam energy should result in an increased sensitivity with respect to the qua...

  1. Coulomb excitation of the odd-odd isotopes $^{106, 108}$In

    CERN Document Server

    Ekstrom, A; Blazhev, A; Van de Walle, J; Weisshaar, D; Zielinska, M; Tveten, G M; Marsh, B A; Siem, S; Gorska, M; Engeland, T; Hurst, A M; Cederkall, J; Finke, F; Iwanicki, J; Hjorth-Jensen, M; Davinson, T; Eberth, J; Sletten, G; Mierzejewski, J; Reiter, P; Warr, N; Butler, P A; Fahlander, C; Stefanescu, I; Koester, U; Ivanov, O; Wenander, F; Voulot, D

    2010-01-01

    The low-lying states in the odd-odd and unstable isotopes In-106,In-108 have been Coulomb excited from the ground state and the first excited isomeric state at the REX-ISOLDE facility at CERN. With the additional data provided here the pi g(9/2)(-1) circle times nu d(5/2) and pi g(9/2)(-1) circle times nu g7/2 multiplets have been re-analyzed and are modified compared to previous results. The observed gamma-ray de-excitation patterns were interpreted within a shell model calculation based on a realistic effective interaction. The agreement between theory and experiment is satisfactory and the calculations reproduce the observed differences in the excitation pattern of the two isotopes. The calculations exclude a 6(+) ground state in In-106. This is in agreement with the conclusions drawn using other techniques. Furthermore, based on the experimental results, it is also concluded that the ordering of the isomeric and ground state in In-108 is inverted compared to the shell model prediction. Limits on B(E2) val...

  2. Analysis of correlation effects in autoionizing doubly excited states of barium using Coulomb Green's function

    International Nuclear Information System (INIS)

    Poirier, M.

    1997-01-01

    Though one would expect that large-angular momentum doubly excited states exhibit weak electronic correlations, it is shown in this paper that a first-order perturbation theory ignoring such correlations may completely fail in predicting correct autoionization probabilities: quadrupolar transitions are poorly described by lowest-order perturbation theory, except for very large angular momenta. Inclusion of second-order dipole-dipole term considerably improves the accuracy of the method. This effect is computed using Coulomb Green's function in its analytical form, probably applied here for the first time to autoionization processes. Examples are given in barium for 5d j 5g [k[ states (j=3/2, 5/2) and for 5d 5/2 nl [k[ states with l > 4. (orig.)

  3. Testing refined shell-model interactions in the sd shell: Coulomb excitation of Na26

    CERN Document Server

    Siebeck, B; Blazhev, A; Reiter, P; Altenkirch, R; Bauer, C; Butler, P A; De Witte, H; Elseviers, J; Gaffney, L P; Hess, H; Huyse, M; Kröll, T; Lutter, R; Pakarinen, J; Pietralla, N; Radeck, F; Scheck, M; Schneiders, D; Sotty, C; Van Duppen, P; Vermeulen, M; Voulot, D; Warr, N; Wenander, F

    2015-01-01

    Background: Shell-model calculations crucially depend on the residual interaction used to approximate the nucleon-nucleon interaction. Recent improvements to the empirical universal sd interaction (USD) describing nuclei within the sd shell yielded two new interactions—USDA and USDB—causing changes in the theoretical description of these nuclei. Purpose: Transition matrix elements between excited states provide an excellent probe to examine the underlying shell structure. These observables provide a stringent test for the newly derived interactions. The nucleus Na26 with 7 valence neutrons and 3 valence protons outside the doubly-magic 16O core is used as a test case. Method: A radioactive beam experiment with Na26 (T1/2=1,07s) was performed at the REX-ISOLDE facility (CERN) using Coulomb excitation at safe energies below the Coulomb barrier. Scattered particles were detected with an annular Si detector in coincidence with γ rays observed by the segmented MINIBALL array. Coulomb excitation cross sections...

  4. Relativistic Coulomb excitation of giant resonances in the hydrodynamic model

    International Nuclear Information System (INIS)

    Vasconcellos Gomes, Ana Cristina de.

    1990-05-01

    We investigate the Coulomb excitation of giant dipole resonances in relativistic heavy ion collisions using a macroscopic hydrodynamical model for the harmonic vibrations of the nuclear fluid. The motion is treated as a combination of the Goldhaber-Teller displacement mode and the Steinwedel-Jensen acoustic mode, and the restoring forces are calculated using the droplet model. This model is used as input to study the characteristics of multiple excitation of giant dipole resonances in nuclei. Possible signatures for the existence of such states are also discussed quantitatively. (author). 52 refs., 14 figs., 3 tabs

  5. Unsafe Coulomb excitation of 240-244Pu

    International Nuclear Information System (INIS)

    Ahmad, I.; Amro, H.; Carpenter, M. P.; Chowdhury, P.; Cizewski, J.; Cline, D.; Greene, J. P.; Hackman, G.; Janssens, R. V. F.; Khoo, T. L.; Lauritsen, T.; Lister, C. J.; Macchiavelli, A. O.; Nisius, D. T.; Reiter, P.; Seabury, E. H.; Seweryniak, D.; Siem, S.; Uusitalo, J.; Wiedenhoever, I.; Wu, C. Y.

    1999-01-01

    The high spin states of 240 Pu and 244 Pu have been investigated with GAMMASPHERE at ATLAS, using Coulomb excitation with a 208 Pb beam at energies above the Coulomb barrier. Data on a transfer channel leading to 242 Pu were obtained as well. In the case of 244 Pu, the yrast band was extended to 34h b ar revealing the completed πi 13/2 alignment, a ''first'' for actinide nuclei. The yrast sequence of 242 Pu was also extended to higher spin and a similar backbend was delineated. In contrast, while the ground state band of 240 Pu was measured up to the highest rotational frequencies ever reported in the actinide region (approximately300 keV), no sign of particle alignment was observed. In this case, several observable such as the large B(E1)/B(E2) branching ratios in the negative parity band, and the vanishing energy staggering between the negative and positive parity bands suggest that the strength of octupole correlations increases with rotational frequency. These stronger correlations may well be responsible for delaying or suppressing the πi 13/2 particle alignment

  6. Prospects for coherently driven nuclear radiation by Coulomb excitation

    International Nuclear Information System (INIS)

    Karamyan, S.A.; Carroll, J.J.

    2006-01-01

    Possible experiments are discussed in which the Coulomb excitation of nuclear isomers would be followed by sequential energy release. The possibility of the coherent Coulomb excitation of nuclei ensconced in a crystal by channeled relativistic heavy projectiles is considered. The phase shift between neighbor-nuclei excitations can be identical to the photon phase shift for emission in forward direction. Thus, the elementary string of atoms can radiate coherently with emission of characteristic nuclear γ rays and the intensity of the radiation could be increased due to the summation of amplitudes. The Moessbauer conditions should be important for this new type of collective radiation that could be promising in the context of the γ-lasing problem

  7. Shape determination in Coulomb excitation of $^{72}$Kr

    CERN Multimedia

    Reiter, P; Kruecken, R; Paul, E S; Wadsworth, R; Heenen, P

    Nuclei with oblate shapes at low spins are very special in nature because of their rarity. Both theoretical and experimental shape co-existence studies in the mass 70 region for near proton drip-line nuclei suggest $^{72}$Kr to be the unique case with oblate low-lying and prolate high-lying levels. However, there is no direct experimental evidence in the literature to date for the oblate nature predicted for the first 2$^+$ state in $^{72}$Kr. We propose to determine the sign of the spectroscopic quadrupole moment of this state via the re-orientation effect in a low-energy Coulomb excitation measurement. In the inelastic excitation of the 2$^+$ state in $^{72}$Kr beam of 3.1 MeV/u with an intensity of 800 pps at REX-ISOLDE impinging on $^{104}$Pd target, the re-orientation effect plays a significant role. The cross section measurement for the 2$^+$ state should thus allow the model-independent determination of the sign of the quadrupole moment unambiguously and will shed light on the co-existing prolate and o...

  8. Hyperon excitation in nuclear coulomb field

    International Nuclear Information System (INIS)

    Vanyashin, A.V.; Nikitin, Yu.P.; Shan'gin, A.A.

    1981-01-01

    A possibility is studied to measure radiative decay partial widths from the 3/2 + decuplet hyperon resonances by means of the Coulomb excitation method of the octet hyperons. The expected contributions from the strong and electromagnetic interactions in the coherence range to the hyperon excitation cross sections on heavy nuclei and on the 4 He nucleus are estimated. The particle angular distributions in the reactions Σ-+A→Σ-(1385)+A and Λ+A→Σ 0 (1385)+A are analysed in order to determine the energy range where the background conditions are the most favorable to extract the electromagnetic mechanism of the hyperon excitation [ru

  9. Coulomb Correlations Intertwined with Spin and Orbital Excitations in LaCoO_{3}.

    Science.gov (United States)

    Tomiyasu, K; Okamoto, J; Huang, H Y; Chen, Z Y; Sinaga, E P; Wu, W B; Chu, Y Y; Singh, A; Wang, R-P; de Groot, F M F; Chainani, A; Ishihara, S; Chen, C T; Huang, D J

    2017-11-10

    We carried out temperature-dependent (20-550 K) measurements of resonant inelastic x-ray scattering on LaCoO_{3} to investigate the evolution of its electronic structure across the spin-state crossover. In combination with charge-transfer multiplet calculations, we accurately quantified the renomalized crystal-field excitation energies and spin-state populations. We show that the screening of the effective on-site Coulomb interaction of 3d electrons is orbital selective and coupled to the spin-state crossover in LaCoO_{3}. The results establish that the gradual spin-state crossover is associated with a relative change of Coulomb energy versus bandwidth, leading to a Mott-type insulator-to-metal transition.

  10. Ground-state configuration of neutron-rich Aluminum isotopes through Coulomb Breakup

    Directory of Open Access Journals (Sweden)

    Chakraborty S.

    2014-03-01

    Full Text Available Neutron-rich 34,35Al isotopes have been studied through Coulomb excitation using LAND-FRS setup at GSI, Darmstadt. The method of invariant mass analysis has been used to reconstruct the excitation energy of the nucleus prior to decay. Comparison of experimental CD cross-section with direct breakup model calculation with neutron in p3/2 orbital favours 34Al(g.s⊗νp3/2 as ground state configuration of 35Al. But ground state configuration of 34Al is complicated as evident from γ-ray spectra of 33Al after Coulomb breakup of 34Al.

  11. Probing nuclear shell structure beyond the N=40 subshell using multiple Coulomb excitation and transfer experiments

    Energy Technology Data Exchange (ETDEWEB)

    Hellgartner, Stefanie Christine

    2015-11-13

    In this work, the N=40 subshell closure is investigated with two complementary methods using a radioactive {sup 72}Zn ISOLDE beam: One- and two-neutron transfer reactions and multiple Coulomb excitation. In the one-neutron transfer reaction, two new levels of {sup 73}Zn were discovered. The two-neutron transfer channel allowed to study the differential cross section of the ground state and the 2{sup +}{sub 1} state of {sup 74}Zn. In the Coulomb excitation experiment, the measured B(E2) values and quadrupole moments of {sup 72}Zn showed that the yrast states 0{sup +}{sub 1}, 2{sup +}{sub 1} and 4{sup +}{sub 1} are moderately collective. Contrary, the 0{sup +}{sub 2} state has a different structure, since it features a stronger closed N=40 configuration compared to the ground state.

  12. Measurements of competing structures in neutron-deficient Pb isotopes by employing Coulomb excitation

    CERN Multimedia

    Bastin, B; Kruecken, R; Larsen, A; Rahkila, P J; Srebrny, J; Clement, E; Wadsworth, R; Syed naeemul, H; Peura, P J; Siem, S; Hadynska-klek, K; Habs, D; Napiorkowski, P J; Diriken, J V J; Iwanicki, J S

    Coulomb excitation measurements to study the shape coexistence and quadrupole collectivity of the low-lying levels in neutron-deficient Pb nuclei are proposed. Even-mass $^{188−192}$Pb nuclei will be post-accelerated at REX-ISOLDE in order to measure transition probabilities and quadrupole moments for the first excited states. In combination with results obtained in lifetime measurements, this will allow the sign of the quadrupole deformation parameter to be extracted for the first time for 2$^{+}$ states in the even-mass $^{188−192}$Pb nuclei.

  13. Coulomb excitation of radioactive Na21 and its stable mirror Ne21

    Science.gov (United States)

    Schumaker, M. A.; Cline, D.; Hackman, G.; Morton, A. C.; Pearson, C. J.; Svensson, C. E.; Wu, C. Y.; Andreyev, A.; Austin, R. A. E.; Ball, G. C.; Bandyopadhyay, D.; Becker, J. A.; Boston, A. J.; Boston, H. C.; Buchmann, L.; Churchman, R.; Cifarelli, F.; Cooper, R. J.; Cross, D. S.; Dashdorj, D.; Demand, G. A.; Dimmock, M. R.; Drake, T. E.; Finlay, P.; Gallant, A. T.; Garrett, P. E.; Green, K. L.; Grint, A. N.; Grinyer, G. F.; Harkness, L. J.; Hayes, A. B.; Kanungo, R.; Leach, K. G.; Lee, G.; Maharaj, R.; Martin, J.-P.; Moisan, F.; Mythili, S.; Nelson, L.; Newman, O.; Nolan, P. J.; Orce, J. N.; Padilla-Rodal, E.; Phillips, A. A.; Porter-Peden, M.; Ressler, J. J.; Roy, R.; Ruiz, C.; Sarazin, F.; Scraggs, D. P.; Waddington, J. C.; Wan, J. M.; Whitbeck, A.; Williams, S. J.; Wong, J.

    2008-10-01

    The low-energy structures of the mirror nuclei Ne21 and radioactive Na21 have been examined by using Coulomb excitation at the TRIUMF-ISAC radioactive ion beam facility. Beams of ~5×106 ions/s were accelerated to 1.7 MeV/A and Coulomb excited in a 0.5 mg/cm2 natTi target. Scattered beam and target particles were detected by the segmented Si detector BAMBINO, while γ rays were observed by using two TIGRESS HPGe clover detectors perpendicular to the beam axis. For each isobar, Coulomb excitation from the (3)/(2)+ ground state to the first excited (5)/(2)+ state was observed and B(E2) values were determined by using the 2+→0+ de-excitation in Ti48 as a reference. The ϕ segmentation of BAMBINO was used to deduce tentative assignments for the signs of the mixing ratios between the E2 and M1 components of the transitions. The resulting B(E2)↑ values are 131±9e2 fm4 (25.4±1.7 W.u.) for Ne21 and 205±14e2 fm4 (39.7±2.7 W.u.) for Na21. The fit to the present data and the known lifetimes determined E2/M1 mixing ratios and B(M1)↓ values of δ=(-)0.0767±0.0027 and 0.1274±0.0025μN2 and δ=(+)0.0832±0.0028 and 0.1513±0.0017μN2 for Ne21 and Na21, respectively (with Krane and Steffen sign convention). By using the effective charges ep=1.5e and en=0.5e, the B(E2) values produced by the p-sd shell model are 30.7 and 36.4 W.u. for Ne21 and Na21, respectively. This analysis resolves a significant discrepancy between a previous experimental result for Na21 and shell-model calculations.

  14. Probing core polarization around 78Ni: intermediate energy Coulomb excitation of 74Ni

    Directory of Open Access Journals (Sweden)

    Marchi T.

    2013-12-01

    We have recently measured the B(E2; 0+ → 2+ of the 74Ni nucleus in an intermediate-energy Coulomb excitation experiment performed at the National Superconducting Cyclotron Laboratory of the Michigan State University. The 74Ni secondary beam has been produced by fragmentation of 86Kr at 140 AMeV on a thick Be target. Selected radioactive fragments impinged on a secondary 197Au target where the measurement of the emitted γ-rays allows to extract the Coulomb excitation cross section and related structure information. Preliminary B(E2 values do not point towards an enhancement of the transition matrix element and the comparison to what was already measured by Aoi and co-workers in [1] opens new scenarios in the interpretation of the shell evolution of the Z=28 isotopes.

  15. Coulomb excitation of the odd-odd isotopes {sup 106,108}In

    Energy Technology Data Exchange (ETDEWEB)

    Ekstroem, A.; Fahlander, C. [University of Lund, Physics Department, Box 118, Lund (Sweden); Cederkaell, J. [University of Lund, Physics Department, Box 118, Lund (Sweden); CERN, PH Department, Geneva 23 (Switzerland); Hjorth-Jensen, M.; Engeland, T. [University of Oslo, Physics Department and Center of Mathematics for Applications, Oslo (Norway); Blazhev, A.; Eberth, J.; Finke, F.; Reiter, P.; Warr, N.; Weisshaar, D. [University of Cologne, Institute of Nuclear Physics, Cologne (Germany); Butler, P.A.; Hurst, A.M. [University of Liverpool, Oliver Lodge Laboratory, Liverpool (United Kingdom); Davinson, T. [University of Edinburgh, Department of Physics and Astronomy, Edinburgh (United Kingdom); Goergen, A. [Service de Physique Nucleaire, CEA Saclay, Gif-sur-Yvette (France); Gorska, M. [Gesellschaft fuer Schwerionenforschung, Darmstadt (Germany); Ivanov, O.; Stefanescu, I. [Instituut voor Kern- en Stralingsfysica, K.U. Leuven (Belgium); Iwanicki, J. [University of Warsaw, Heavy Ion Laboratory, Warsaw (Poland); Koester, U. [CERN, PH Department, Geneva 23 (Switzerland); Institut Laue Langevin, Grenoble (France); Marsh, B.A. [University of Manchester, Department of Physics, Manchester (United Kingdom); CERN, AB Department, Geneva 23 (Switzerland); Mierzejewski, J. [University of Warsaw, Heavy Ion Laboratory, Warsaw (Poland); University of Warsaw, Institute of Experimental Physics, Warsaw (Poland); Siem, S. [University of Oslo, Department of Physics, Oslo (Norway); Sletten, G. [University of Copenhagen, Physics Department, Copenhagen (Denmark); Tveten, G.M. [CERN, PH Department, Geneva 23 (Switzerland); University of Oslo, Department of Physics, Oslo (Norway); Van de Walle, J. [CERN, PH Department, Geneva 23 (Switzerland); Instituut voor Kern- en Stralingsfysica, K.U. Leuven (Belgium); Voulot, D.; Wenander, F. [CERN, AB Department, Geneva 23 (Switzerland)

    2010-06-15

    The low-lying states in the odd-odd and unstable isotopes {sup 106,108}In have been Coulomb excited from the ground state and the first excited isomeric state at the REX-ISOLDE facility at CERN. With the additional data provided here the {pi}g{sub 9/2}{sup -1} x {nu}d{sub 5/2} and {pi}g{sub 9/2}{sup -1} x {nu} g{sub 7/2} multiplets have been re-analyzed and are modified compared to previous results. The observed {gamma} -ray de-excitation patterns were interpreted within a shell model calculation based on a realistic effective interaction. The agreement between theory and experiment is satisfactory and the calculations reproduce the observed differences in the excitation pattern of the two isotopes. The calculations exclude a 6{sup +} ground state in {sup 106}In. This is in agreement with the conclusions drawn using other techniques. Furthermore, based on the experimental results, it is also concluded that the ordering of the isomeric and ground state in {sup 108}In is inverted compared to the shell model prediction. Limits on B(E2) values have been extracted where possible. A previously unknown low-lying state at 367keV in {sup 106}In is also reported. (orig.)

  16. Low-energy Coulomb excitation of $^{62}$Fe and $^{62}$Mn following in-beam decay of $^{62}$Mn

    CERN Document Server

    Gaffney, L P; Bastin, B; Bildstein, V; Blazhev, A; Bree, N; Darby, I; De Witte, H; DiJulio, D; Diriken, J; Fedosseev, V N; Fransen, Ch; Gernhäuser, R; Gustafsson, A; Hess, H; Huyse, M; Kesteloot, N; Kröll, Th; Lutter, R; Marsh, B A; Reiter, P; Seidlitz, M; Van Duppen, P; Voulot, D; Warr, N; Wenander, F; Wimmer, K; Wrzosek-Lipska, K

    2015-01-01

    Sub-barrier Coulomb-excitation was performed on a mixed beam of $^{62}$Mn and $^{62}$Fe, following in-trap $\\beta^{-}$ decay of $^{62}$Mn at REX-ISOLDE, CERN. The trapping and charge breeding times were varied in order to alter the composition of the beam, which was measured by means of an ionisation chamber at the zero-angle position of the Miniball array. A new transition was observed at 418 keV, which has been tentatively associated to a $2^{(+)},3^{(+)}\\rightarrow1^{+}_{g.s.}$ transition. This fixes the relative positions of the $\\beta$-decaying $4^{(+)}$ and $1^{+}$ states in $^{62}$Mn for the first time. Population of the $2^{+}_{1}$ state was observed in $^{62}$Fe and the cross-section determined by normalisation to the $^{109}$Ag target excitation. Combining this Coulomb-excitation cross-section with previously measured lifetimes of the $2^{+}_{1}$ state, the spectroscopic quadrupole moment, $Q_{s}(2^{+}_{1})$, is extracted, albeit with a large uncertainty.

  17. On alignment of deformed nucleus spins as the result of coulomb excitation

    International Nuclear Information System (INIS)

    Aleshin, V.P.; Ofengenden, S.R.

    1981-01-01

    In the framework of sudden impact approximation excitation probabilities and spiral distributions at Coulomb excitation of rotational levels by means of heavy ions are considered. Considerable attention is given to the accuracy of the qsub(ef)(THETA) approximation being a particular case of impact sudden approximation according to which at Coulomb of the even-even nuclei excitation the I spins of excited states are aligned perpendicularly to the symmetry axis of the Rutherford orbit. The analysis of the problem in the framework of a quasiclassical approximation has shown that the greatest deviations of qsub(ef)(THETA) approximation (at fixed constant of a quadrupole interaction q) occur for average scattering angles. Quanta calculation results are given at THETA=90 deg in the range q=0-10 for I=0-18. It has been found that excitation probabilities for dominating transitions are described in the qsub(ef)(THETA) approximation with an error being not higher than 1-2%. At I>=6 the greatest relative errors of the qsub(ef)(THETA) approximation when describing P 1 excitation probabilities do not exceed 30-40%. The relative errors at the description of spiral distributions may reach values being several times greater than the errors in corresponding excitation probabilities. It has been found that at I>=6 spiral distributions have two symmetrically situated maxima concentrated near h=+-hm, where hm=I cos (THETA/2). In the framework the of qsub(ef)(THETA) approximation in these maxima concentrated are from 50 to 70%, or to he exact - up to 80% of P 1 excitation probability [ru

  18. Electric quadrupole excitation of the first excited state of 11B

    International Nuclear Information System (INIS)

    Fewell, M.P.; Spear, R.H.; Zabel, T.H.; Baxter, A.M.

    1980-02-01

    The Coulomb excitation of backscattered 11 B projectiles has been used to measure the reduced E2 transition probability B(E2; 3/2 - →1/2 - ) between the 3/2 - ground state and the 1/2 - first excited state of 11 B. It is found that B(E2; 3/2 - →1/2 - ) = 2.1 +- 0.4 e 2 fm 4 , which agrees with shell-model predictions but is a factor of 10 larger than the prediction of the core-excitation model

  19. Semiclassical treatment of nuclear effects in Coulomb excitation

    Energy Technology Data Exchange (ETDEWEB)

    Canto, L F; Donangelo, R [Universidade Federal do Rio de Janeiro, RJ (Brazil). Inst. de Fisica; Rasmussen, J O; Ring, P; Stoyer, M A [Lawrence Berkeley Lab., CA (USA). Nuclear Science Div.

    1990-09-27

    We introduce the effects of the nuclear potential in the semiclassical Alder-Winther-de Boer method, both in the coupling matrix elements and as corrections to the Rutherford orbit. We compare our results to those of pure Coulomb excitation and to coupled-channel calculations. (orig.).

  20. Computer experiments of the time-sequence of individual steps in multiple Coulomb-excitation

    International Nuclear Information System (INIS)

    Boer, J. de; Dannhaueser, G.

    1982-01-01

    The way in which the multiple E2 steps in the Coulomb-excitation of a rotational band of a nucleus follow one another is elucidated for selected examples using semiclassical computer experiments. The role a given transition plays for the excitation of a given final state is measured by a quantity named ''importance function''. It is found that these functions, calculated for the highest rotational state, peak at times forming a sequence for the successive E2 transitions starting from the ground state. This sequential behaviour is used to approximately account for the effects on the projectile orbit of the sequential transfer of excitation energy and angular momentum from projectile to target. These orbits lead to similar deflection functions and cross sections as those obtained from a symmetrization procedure approximately accounting for the transfer of angular momentum and energy. (Auth.)

  1. Coulomb and nuclear excitations of narrow resonances in 17Ne

    Directory of Open Access Journals (Sweden)

    J. Marganiec

    2016-08-01

    Full Text Available New experimental data for dissociation of relativistic 17Ne projectiles incident on targets of lead, carbon, and polyethylene targets at GSI are presented. Special attention is paid to the excitation and decay of narrow resonant states in 17Ne. Distributions of internal energy in the O15+p+p three-body system have been determined together with angular and partial-energy correlations between the decay products in different energy regions. The analysis was done using existing experimental data on 17Ne and its mirror nucleus 17N. The isobaric multiplet mass equation is used for assignment of observed resonances and their spins and parities. A combination of data from the heavy and light targets yielded cross sections and transition probabilities for the Coulomb excitations of the narrow resonant states. The resulting transition probabilities provide information relevant for a better understanding of the 17Ne structure.

  2. Enhanced population of side band of {sup 155}Gd in heavy-ion Coulomb excitation

    Energy Technology Data Exchange (ETDEWEB)

    Oshima, Masumi; Hayakawa, Takehito; Hatsukawa, Yuichi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; and others

    1998-03-01

    In the Coulomb excitation of {sup 155}Gd with heavy projectiles, {sup 32}S, {sup 58}Ni and {sup 90}Zr, unexpectedly large enhancement of a positive-parity side band has been observed. This enhancement could not be reproduced by a Coulomb-excitation calculation taking into account the recommended upper limits of E1 or E3 transitions, which are compiled in the whole mass region, and is proportional to the electric field accomplished in the Coulomb-scattering process. (author)

  3. Transfer reactions and multiple Coulomb excitation in the $^{100}$Sn Region

    CERN Multimedia

    It is proposed to continue our REX-ISOLDE program in the $^{100}$Sn region at HIE-ISOLDE at ~5 MeV/u. Earlier measurements, with a precision of 10-20%, at 3 MeV/u with REX-ISOLDE point to a deviation between the measured B(E2) values for the first excited 2$^{+}$ states in $^{110,108,106}$Sn compared to theoretical predictions. In addition, the trend of B(E2) values for the lighter isotopes, in particular $^{106}$Sn, appear to differ between low- and high-energy measurements. In line with our letter-of-intent we aim in a first step to address the electromagnetic properties of the first 2$^{+}$and 4$^{+}$ states in $^{110,108,106}$Sn using Coulomb excitation. In these measurements we will directly access the lifetimes of the first excited 4$^{+}$ states in $^{110,108,106}$Sn for the first time. The yield of $^{104}$Sn from the LaC$_{x}$ target will be revisited to clarify if the new solid state RILIS gives sufficient yield to expand the measurements to this isotope. Following this proposal we plan similar meas...

  4. Multiple Coulomb excitation effects in heavy ion compound and fusion cross sections

    International Nuclear Information System (INIS)

    Carlson, B.V.; Hussein, M.S.

    1981-11-01

    A simple model for the average S-matrix that describes heavy ion direct processes in the presence of absorption due to compound nucleus formation is developed. The fluctuation cross section and the fusion cross section are then calculated for deformed heavy ion systems where multiple Coulomb excitation is important. A simple expression for the fusion cross section valid for above-barrier energies is then obtained. The formula clearly displays the modification, due to Coulomb excitation, in the usual geometrical expression. (Author) [pt

  5. Shape coexistence in the neutron-deficient mercury isotopes studied through Coulomb excitation

    CERN Document Server

    Bree, Nick

    This thesis describes the analysis and results of a series of Coulomb-excitation experiments on even-even neutron-deficient mercury isotopes aimed at obtaining a more detailed description of shape coexistence. Two experimental campaigns have been undertaken in the Summer of 2007 and 2008. Pure beams of 182,184,186,188Hg were produced and accelerated at the REX-ISOLDE radioactive-beam facility, located at CERN (Geneva, Switzerland). The beams were guided to collide with a stable target to induce Coulomb excitation. The scattered particles were registered by a double-sided silicon strip detector, and the emitted gamma rays by the MINIBALL gamma-ray spectrometer. The motivation to study these mercury isotopes, focused around shape coexistence in atomic nuclei, is addressed in chapter 1, as well as an overview of the knowledge in this region of the nuclear chart. A theoretical description of Coulomb excitation is presented in the second chapter, while the third chapter describes the setup employed for the experim...

  6. Shape coexistence in the neutron-deficient even-even (182-188)Hg isotopes studied via coulomb excitation.

    Science.gov (United States)

    Bree, N; Wrzosek-Lipska, K; Petts, A; Andreyev, A; Bastin, B; Bender, M; Blazhev, A; Bruyneel, B; Butler, P A; Butterworth, J; Carpenter, M P; Cederkäll, J; Clément, E; Cocolios, T E; Deacon, A; Diriken, J; Ekström, A; Fitzpatrick, C; Fraile, L M; Fransen, Ch; Freeman, S J; Gaffney, L P; García-Ramos, J E; Geibel, K; Gernhäuser, R; Grahn, T; Guttormsen, M; Hadinia, B; Hadyńska-Kle K, K; Hass, M; Heenen, P-H; Herzberg, R-D; Hess, H; Heyde, K; Huyse, M; Ivanov, O; Jenkins, D G; Julin, R; Kesteloot, N; Kröll, Th; Krücken, R; Larsen, A C; Lutter, R; Marley, P; Napiorkowski, P J; Orlandi, R; Page, R D; Pakarinen, J; Patronis, N; Peura, P J; Piselli, E; Rahkila, P; Rapisarda, E; Reiter, P; Robinson, A P; Scheck, M; Siem, S; Singh Chakkal, K; Smith, J F; Srebrny, J; Stefanescu, I; Tveten, G M; Van Duppen, P; Van de Walle, J; Voulot, D; Warr, N; Wenander, F; Wiens, A; Wood, J L; Zielińska, M

    2014-04-25

    Coulomb-excitation experiments to study electromagnetic properties of radioactive even-even Hg isotopes were performed with 2.85  MeV/nucleon mercury beams from REX-ISOLDE. Magnitudes and relative signs of the reduced E2 matrix elements that couple the ground state and low-lying excited states in Hg182-188 were extracted. Information on the deformation of the ground and the first excited 0+ states was deduced using the quadrupole sum rules approach. Results show that the ground state is slightly deformed and of oblate nature, while a larger deformation for the excited 0+ state was noted in Hg182,184. The results are compared to beyond mean field and interacting-boson based models and interpreted within a two-state mixing model. Partial agreement with the model calculations was obtained. The presence of two different structures in the light even-mass mercury isotopes that coexist at low excitation energy is firmly established.

  7. /B(E2) values from low-energy Coulomb excitation at an ISOL facility: the /N=80,82 Te isotopes

    Science.gov (United States)

    Barton, C. J.; Caprio, M. A.; Shapira, D.; Zamfir, N. V.; Brenner, D. S.; Gill, R. L.; Lewis, T. A.; Cooper, J. R.; Casten, R. F.; Beausang, C. W.; Krücken, R.; Novak, J. R.

    2003-01-01

    B(E2;0+1→2+1) values for the unstable, neutron-rich nuclei 132,134Te were determined through Coulomb excitation, in inverse kinematics, of accelerated beams of these nuclei. The systematics of measured B(E2) values from the ground state to the first excited state have been extended to the N=82 shell closure in the Te nuclei and have been compared with the predictions of different theories. The measurements were performed at the Holifield Radioactive Ion Beam Facility (HRIBF) using the GRAFIK detector. The success of this approach, which couples a 5.7% efficient through-well NaI(Tl) γ-ray detector with thin foil microchannel plate beam detectors, also demonstrates the feasibility for Coulomb excitation studies of neutron-rich nuclei even further from the valley of beta stability, both at present-generation ISOL facilities and at the proposed Rare Isotope Accelerator.

  8. Scaling laws and higher-order effects in Coulomb excitation of neutron halo nuclei

    International Nuclear Information System (INIS)

    Typel, S.; Baur, G.

    2008-01-01

    Essential properties of halo nuclei can be described in terms of a few low-energy constants. For neutron halo nuclei, analytical results can be found for wave functions and electromagnetic transition matrix elements in simple but well-adapted models. These wave functions can be used to study nuclear reactions; an especially simple and instructive example is Coulomb excitation. A systematic expansion in terms of small parameters can be given. We present scaling laws for excitation amplitudes and cross-sections. The results can be used to analyze experiments like 11 Be Coulomb excitation. They also serve as benchmark tests for more involved reaction theories. (orig.)

  9. Onset of collectivity in $^{96,98}$Sr studied via Coulomb excitation

    CERN Document Server

    Clement, E; Dijon, A; de France, G; Bastin, B; Blazhev, A; Bree, N; Butler, P; Delahaye, P; Ekstrom, A; Georgiev, G; Hasan, N; Iwanicki, J; Jenkins, D; Korten, W; Larsen, A C; Ljungvall, J; Moschner, K; Napiorkowski, P; Pakarinen, J; Petts, A; Renstrom, T; Seidlitz, M; Siem, S; Sotty, C; Srebrny, J; Stefanescu, I; Tveten, G M; Van de Walle, J; Warr, N; Wrzosek-Lipska, K; Zielinska, M; Bauer, C; Bruyneel, B; Butterworth, J; Fitzpatrick, C; Fransen, C; GernhäUser, R; Hess, H; Lutter, R; Marley, P; Reiter, P; Siebeck, B; Vermeulen, M; Wiens, A; De Witte, H

    2014-01-01

    A rapid onset of quadrupole deformation is known to occur around the neutron number 60 in the neutron-rich Zr and Sr isotopes. This shape change has made the neutron-rich A = 100 region an active area of experimental and theoretical studies for many decades now. We report in this contribution new experimental results in the neutron rich 96,98Sr investigated by safe Coulomb excitation of radioactive beams at the REX-ISOLDE facility, CERN. Reduced transition probabilities and spectroscopic quadrupole moments have been extracted from the differential Coulomb excitation cross section supporting the scenario of shape coexistence/change at N=60. Future perspectives are presented including the recent experimental campaign performed at ILL-Grenoble.

  10. Onset of collectivity in 96,98Sr studied via Coulomb excitation

    Directory of Open Access Journals (Sweden)

    Clément E.

    2014-03-01

    Full Text Available A rapid onset of quadrupole deformation is known to occur around the neutron number 60 in the neutron-rich Zr and Sr isotopes. This shape change has made the neutron-rich A = 100 region an active area of experimental and theoretical studies for many decades now. We report in this contribution new experimental results in the neutron rich 96,98Sr investigated by safe Coulomb excitation of radioactive beams at the REX-ISOLDE facility, CERN. Reduced transition probabilities and spectroscopic quadrupole moments have been extracted from the differential Coulomb excitation cross section supporting the scenario of shape coexistence/change at N=60. Future perspectives are presented including the recent experimental campaign performed at ILL-Grenoble.

  11. Measurements of shape co-existence in $^{182,184}$Hg using Coulomb excitation

    CERN Multimedia

    Voulot, D; Paul, E S; Siem, S; Czosnyka, T; Napiorkowski, P J; Iwanicki, J S

    2007-01-01

    We propose to exploit the unique capability of ISOLDE to provide post-accelerated $^{182,184}$Hg ions from the REX facility to enable the lowest states of these nuclei to be Coulomb excited. By measuring the $\\gamma$-ray yields using the MINIBALL array we can measure the transition and diagonal E2 matrix elements for these states. This will give quantitative information about the nature of the shape coexistence in these nuclei and allow the sign of the quadrupole deformation be determined for the first time. We require 24 shifts to fulfill the aims of the experiment.

  12. Coulomb excitation of /sup 182/ /sup 184/ /sup 186/W and /sup 166/Er with /sup 4/He and /sup 16/O ions

    Energy Technology Data Exchange (ETDEWEB)

    McGowan, F K; Milner, W T; Sayer, R O; Robinson, R L; Stelson, P H [Oak Ridge National Lab., Tenn. (USA)

    1977-10-10

    The Coulomb excitation reaction induced by /sup 4/He ions selectively excites 2/sup +/ and 3/sup -/ states by direct E2 and E3 Coulomb excitation. In this paper, new results are presented from ..gamma..-ray spectroscopy with 15 MeV /sup 4/He ions on a natural abundance target of W. In particular, a 3/sup -/ state in each isotope, /sup 182/ /sup 184/ /sup 186/W, was observed by direct E3 excitation. In addition to obtaining B(Elambda, 0 ..-->.. J = lambda for excitation of each state, information on the reduced transition probabilities for the different decay modes of these states is given. The Coulomb excitation probabilities of the 2'/sup +/ states at 786 keV in /sup 166/Er and at 737 keV in /sup 186/W were measured with /sup 16/O and /sup 4/He ions by the backscattered particle-gamma coincidence method in order to determine the static electric quadrupole moment Qsub(2'). For /sup 166/Er, Qsub(2')=2.11+-0.37 e.b which is in agreement with (Qsub(2'))sub(rot) and for /sup 186/W, Qsub(2')=1.17+-0.30 e.b which is in agreement with Kumar-Baranger model calculations and is significantly smaller than (Qsub(2'))sub(rot). This deviation of the measured Qsub(2') from (Qsub(2'))sub(rot) implies in the framework of the Kumar-Baranger calculations a strong coupling between ..beta..- and ..gamma..-vibrational bands. On the other hand, the observed upper limit for B(E2, 2'' ..-->.. 2') does not confirm this implication.

  13. Coulomb excitation of 206Hg at relativistic energies

    Science.gov (United States)

    Alexander, Tom

    The region of the nuclear chart surrounding the doubly-magic nucleus 208Pb provides a key area to constrain and develop contemporary nuclear structure models. One aspect of particular interest is the transition strength of the first excited 2+ state in even-even nuclei; this work describes the measurement of this value for the case of 206Hg, where the Z=80 line meets the N=126 shell closure. The nuclei of interest were synthesized using relativistic-energy projectile fragmentation at the GSI facility in Germany. They were produced in the fragmentation of a primary 208Pb beam at an energy of 1 GeV per nucleon, and separated and identifed using the Fragment Separator. The secondary beams with an energy of 140 MeV per nucleon were Coulomb excited on a secondary target of 400 mg/cm. 2 gold. Gamma-rays were detected with the Advanced GAmma Tracking Array (AGATA). The precise scattering angle for Doppler-correction was determined with position information from the Lund-York-Cologne-CAlorimeter(LYCCA). Using the sophisticated tracking algorithm native to AGATA in conjunction with pulse-shape analysis, a precise Doppler-correction is performed on the gamma spectra, and using a complex n-dimensional analysis, the B(E2) value for 206Hg is extracted relative to the known value also measured in 206Pb. A total of 409 million 206Hg particles were measured, and a cross-section of 50 mb was determined for the 2+ state at 1068 keV. The measurement of the B(E2) transition strength was found to be 1.109 W.u. This result is compared to a number of theoretical calculations, including two Gogny forces, and a modified shell model parametrization and is found to be smaller than all calculated estimations, implying that the first excited 2. + state in . {206}Hg is uncollective in nature.

  14. Photoionization of furan from the ground and excited electronic states.

    Science.gov (United States)

    Ponzi, Aurora; Sapunar, Marin; Angeli, Celestino; Cimiraglia, Renzo; Došlić, Nađa; Decleva, Piero

    2016-02-28

    Here we present a comparative computational study of the photoionization of furan from the ground and the two lowest-lying excited electronic states. The study aims to assess the quality of the computational methods currently employed for treating bound and continuum states in photoionization. For the ionization from the ground electronic state, we show that the Dyson orbital approach combined with an accurate solution of the continuum one particle wave functions in a multicenter B-spline basis, at the density functional theory (DFT) level, provides cross sections and asymmetry parameters in excellent agreement with experimental data. On the contrary, when the Dyson orbitals approach is combined with the Coulomb and orthogonalized Coulomb treatments of the continuum, the results are qualitatively different. In excited electronic states, three electronic structure methods, TDDFT, ADC(2), and CASSCF, have been used for the computation of the Dyson orbitals, while the continuum was treated at the B-spline/DFT level. We show that photoionization observables are sensitive probes of the nature of the excited states as well as of the quality of excited state wave functions. This paves the way for applications in more complex situations such as time resolved photoionization spectroscopy.

  15. D-wave resonances in three-body system Ps- with pure Coulomb and screened Coulomb (Yukawa) potentials

    International Nuclear Information System (INIS)

    Kar, S.; Ho, Y.K.

    2009-01-01

    We have investigated the doubly excited 1 D e resonance states of Ps - interacting with pure Coulomb and screened Coulomb (Yukawa) potentials employing highly correlated wave functions. For pure Coulomb interaction, in the framework of stabilization method and complex coordinate rotation method we have obtained two resonances below the n = 2 threshold of the Ps atom. For screened Coulomb interaction, we employ the stabilization method to extract resonance parameters. Resonance energies and widths for the 1 D e resonance states of Ps - for different screening parameter ranging from infinity (pure Coulomb case) to a small value are also reported. (author)

  16. Coulomb excitations for a short linear chain of metallic shells

    Energy Technology Data Exchange (ETDEWEB)

    Zhemchuzhna, Liubov, E-mail: lzhemchuzhna@unm.edu [Department of Physics and Astronomy, Hunter College of the City University of New York, 695 Park Avenue, New York, New York 10065 (United States); Center for High Technology Materials, University of New Mexico, Albuquerque, New Mexico 87106 (United States); Gumbs, Godfrey [Department of Physics and Astronomy, Hunter College of the City University of New York, 695 Park Avenue, New York, New York 10065 (United States); Donostia International Physics Center (DIPC), P de Manuel Lardizabal, 4, 20018 San Sebastian, Basque Country (Spain); Iurov, Andrii [Center for High Technology Materials, University of New Mexico, Albuquerque, New Mexico 87106 (United States); Huang, Danhong [Air Force Research Laboratory, Space Vehicles Directorate, Kirtland Air Force Base, New Mexico 87117 (United States); Gao, Bo [Department of Physics and Astronomy, Hunter College of the City University of New York, 695 Park Avenue, New York, New York 10065 (United States)

    2015-03-15

    A self-consistent-field theory is given for the electronic collective modes of a chain containing a finite number, N, of Coulomb-coupled spherical two-dimensional electron gases arranged with their centers along a straight line, for simulating electromagnetic response of a narrow-ribbon of metallic shells. The separation between nearest-neighbor shells is arbitrary and because of the quantization of the electron energy levels due to their confinement to the spherical surface, all angular momenta L of the Coulomb excitations, as well as their projections M on the quantization axis, are coupled. However, for incoming light with a given polarization, only one angular momentum quantum number is usually required. Therefore, the electromagnetic response of the narrow-ribbon of metallic shells is expected to be controlled externally by selecting different polarizations for incident light. We show that, when N = 3, the next-nearest-neighbor Coulomb coupling is larger than its value if they are located at opposite ends of a right-angle triangle forming the triad. Additionally, the frequencies of the plasma excitations are found to depend on the orientation of the line joining them with respect to the axis of quantization since the magnetic field generated from the induced oscillating electric dipole moment on one sphere can couple to the induced magnetic dipole moment on another. Although the transverse inter-shell electromagnetic coupling can be modeled by an effective dynamic medium, the longitudinal inter-shell Coulomb coupling, on the other hand, can still significantly modify the electromagnetic property of this effective medium between shells.

  17. Lifetime measurements of excited states in 196Pt

    International Nuclear Information System (INIS)

    Bolotin, H.H.; Katayama, Ichiro; Sakai, Hideyuki; Fujita, Yoshitaka; Fujiwara, Mamoru

    1979-01-01

    The lifetimes of six excited states in 196 Pt up to an excitation energy of 1525 keV were measured by the recoil-distance method (RDM). These levels were populated by Coulomb excitation using both 90 MeV 20 Ne and 220 MeV 58 Ni ion beams. The measured lifetimes of the 2 1 + , 4 1 + , 6 1 + , 2 2 + , 4 2 + and 0 2 + states and the B(E2) values inferred for the depopulating transitions from these levels are presented. With the exception of the 2 1 + state, the meanlives of all other levels are the first such direct experimental determinations to be reported. (author)

  18. Study of the N=40 shell by using Coulomb excitation

    International Nuclear Information System (INIS)

    Leenhardt, St.

    2000-01-01

    Two Coulomb excitation experiments on neutron rich exotic nuclei have been performed at GANIL. They allowed the measurement of the reduced transition probability B(E2) (from ground state to first excited state) of some nuclei around N = 40. This number, 40, is a half-magic number in the shell model. For nuclei with an important neutron excess, it is predicted that the shell closure is stronger at N = 40. The B(E2) is a good tool for testing this growing. We have measured, by using the LISE3 spectrometer and a γ multidetector, B(E2) of 68 Ni, 66 Ni and 72 Zn, unknown till now. We have used for the first time segmented germanium 'clovers' detector, for photon detection (v/c∼0.3). Results confirm the strong shell effect for 68 Ni. Indeed 68 Ni was shown to be the Nickel isotope with the lowest value of B(E2), and hence the most rigid isotope. Nevertheless it seems that the shell effect at N = 40 decreases rapidly, for other isotopes very close to 68 Ni(Z = 28) and N = 40). (authors)

  19. Coulomb excitation of doubly magic $^{132}$Sn with MINIBALL at HIE-ISOLDE

    CERN Multimedia

    We propose to study the vibrational first 2$^{+}$ and 3$^{-}$ states of the doubly magic nucleus $^{132}$ Sn via Coulomb excitation using the HIE-ISOLDE facility coupled with the highly efficient MINIBALL array. The intense $^{132}$Sn beam at ISOLDE, the high beam energy of HIE-ISOLDE, the high energy resolution and good efficiency of the MINIBALL provide a unique combination and favourable advantages to master this demanding measurement. Reliable B(E2;0$^{+}\\rightarrow$ 2$^{+}$) values for neutron deficient $^{106,108,110}$Sn were obtained with the MINIBALL at REX-ISOLDE. These measurements can be extended up to and beyond the shell closure at the neutron-rich side with $^{132}$Sn. The results on excited collective states in $^{132}$Sn will provide crucial information on 2p-2h cross shell configurations which are expected to be dominated by a strong proton contribution. Predictions are made within various large scale shell model calculations and new mean field calculations within the framework of different a...

  20. Shape coexistence in neutron-rich Sr isotopes : Coulomb excitation of $^{96}$Sr

    CERN Multimedia

    Clement, E; Siem, S; Czosnyka, T

    2007-01-01

    The nuclei in the mass region A $\\cong$ 100 around Sr and Zr show a dramatic change of the nuclear ground-state shape from near spherical for N $\\leq$ 58 to strongly deformed for N $\\geq$ 60. Theoretical calculations predict the coexistence of slightly oblate and strongly prolate deformed configurations in the transitional region. However, excited rotational structures based on the highly deformed configuration, which becomes the ground state at N = 60, are not firmly established in the lighter isotopes, and the earlier interpretation of a very abrupt change of shape has been challenged by recent experimental results in favor of a rather gradual change. We propose to study the electromagnetic properties of the neutron-rich nucleus $_{38}^{96}$Sr$_{58}$ by low-energy Coulomb excitation using the REX-ISOLDE facility and the MINIBALL detector array. Both transitional and diagonal matrix elements will be extracted, resulting in a complete description of the transition strengths and quadrupole moments of the low-l...

  1. Shape coexistence in krypton and selenium light isotopes studied through Coulomb excitation of radioactive ions beams; Etude de la coexistence de formes dans les isotopes legers du krypton et du selenium par excitation Coulombienne de faisceaux radioactifs

    Energy Technology Data Exchange (ETDEWEB)

    Clement, E

    2006-06-15

    The light krypton isotopes show two minima in their potential energy corresponding to elongated (prolate) and compressed (oblate) quadrupole deformation. Both configuration are almost equally bound and occur within an energy range of less than 1 MeV. Such phenomenon is called shape coexistence. An inversion of the ground state deformation from prolate in Kr{sup 78} to oblate in Kr{sup 72} with strong mixing of the configurations in Kr{sup 74} and Kr{sup 76} was proposed based on the systematic of isotopic chain. Coulomb excitation experiments are sensitive to the quadrupole moment. Coulomb excitation experiments of radioactive Kr{sup 74} and Kr{sup 76} beam were performed at GANIL using the SPIRAL facility and the EXOGAM spectrometer. The analysis of these experiments resulted in a complete description of the transition strength and quadrupole moments of the low-lying states. They establish the prolate character of the ground state and an oblate excited state. A complementary lifetime measurement using a 'plunger' device was also performed. Transition strength in neighboring nuclei were measured using the technique of intermediate energy Coulomb excitation at GANIL. The results on the Se{sup 68} nucleus show a sharp change in structure with respects to heavier neighboring nuclei. (author)

  2. Study of Ground State Wave-function of the Neutron-rich 29,30Na Isotopes through Coulomb Breakup

    Directory of Open Access Journals (Sweden)

    Rahaman A.

    2014-03-01

    Full Text Available Coulomb breakup of unstable neutron rich nuclei 29,30Na around the ‘island of inversion’ has been studied at energy around 434 MeV/nucleon and 409 MeV/nucleon respectively. Four momentum vectors of fragments, decay neutron from excited projectile and γ-rays emitted from excited fragments after Coulomb breakup are measured in coincidence. For these nuclei, the low-lying dipole strength above one neutron threshold can be explained by direct breakup model. The analysis for Coulomb breakup of 29,30Na shows that large amount of the cross section yields the 28Na, 29Na core in ground state. The predominant ground-state configuration of 29,30Na is found to be 28Na(g.s⊗νs1/2 and 29Na(g.s⊗νs1/2,respectively.

  3. Reply to "Comment on 'Calculations for the one-dimensional soft Coulomb problem and the hard Coulomb limit' ".

    Science.gov (United States)

    Gebremedhin, Daniel H; Weatherford, Charles A

    2015-02-01

    This is a response to the comment we received on our recent paper "Calculations for the one-dimensional soft Coulomb problem and the hard Coulomb limit." In that paper, we introduced a computational algorithm that is appropriate for solving stiff initial value problems, and which we applied to the one-dimensional time-independent Schrödinger equation with a soft Coulomb potential. We solved for the eigenpairs using a shooting method and hence turned it into an initial value problem. In particular, we examined the behavior of the eigenpairs as the softening parameter approached zero (hard Coulomb limit). The commenters question the existence of the ground state of the hard Coulomb potential, which we inferred by extrapolation of the softening parameter to zero. A key distinction between the commenters' approach and ours is that they consider only the half-line while we considered the entire x axis. Based on mathematical considerations, the commenters consider only a vanishing solution function at the origin, and they question our conclusion that the ground state of the hard Coulomb potential exists. The ground state we inferred resembles a δ(x), and hence it cannot even be addressed based on their argument. For the excited states, there is agreement with the fact that the particle is always excluded from the origin. Our discussion with regard to the symmetry of the excited states is an extrapolation of the soft Coulomb case and is further explained herein.

  4. Measurements of octupole collectivity in $^{220,222}$Rn and $^{222,224}$Ra using Coulomb excitation

    CERN Multimedia

    Kruecken, R; Larsen, A; Hurst, A M; Voulot, D; Grahn, T; Clement, E; Wadsworth, R; Gernhaeuser, R A; Siem, S; Huyse, M L; Iwanicki, J S

    2008-01-01

    We propose to exploit the unique capability of ISOLDE to provide post-accelerated $^{220,222}$Rn and $^{222,224}$Ra ion beams from the REX facility to enable the Coulomb excitation of the first 3$^{-}$ states in these nuclei. By measuring the $\\gamma$-ray yields of the E1 decays from the 3$^{-}$ state using the MINIBALL array we can obtain the transition matrix elements. This will give quantitative information about octupole correlations in these nuclei. We require 22 shifts to fulfil the aims of the experiment.

  5. Plunger lifetime measurements after Coulomb excitation at intermediate beam energies

    Energy Technology Data Exchange (ETDEWEB)

    Hackstein, Matthias; Dewald, Alfred; Fransen, Christoph; Ilie, Gabriela; Jolie, Jan; Melon, Barbara; Pissulla, Thomas; Rother, Wolfram; Zell, Karl-Oskar [University of Cologne (Germany); Petkov, Pavel [University of Cologne (Germany); INRNE (Bulgaria); Chester, Aaron; Adrich, Przemyslaw; Bazin, Daniel; Bowen, Matt; Gade, Alexandra; Glasmacher, Thomas; Miller, Dave; Moeller, Victoria; Starosta, Krzysztof; Stolz, Andreas; Vaman, Constantin; Voss, Philip; Weissharr, Dirk [Michigan State Univerity (United States); Moeller, Oliver [TU Darmstadt (Germany)

    2008-07-01

    Two recoil-distance-doppler-shift (RDDS) experiments were performed at the NSCL/MSU using Coulomb excitations of the projectile nuclei {sup 110}Pd, {sup 114}Pd at beam energies of 54 MeV/u in order to investigate the evolution of deformation of neutron rich paladium isotopes. The experimental set-up consisted of a dedicated plunger device, developed at the University of Cologne, the SEGA Ge-array and the S800 spectrometer. Lifetimes of the 2{sub 1}{sup +}-states in {sup 110}Pd and {sup 114}Pd were derived from the analysis of the {gamma}-line-shapes as well as from the measured decay-curves. Special features of the data analysis, e.g. features originating from the very high recoil velocities, are discussed.

  6. Nuclear structure studies of the neutron-rich Rubidium isotopes using Coulomb excitation

    CERN Multimedia

    Reiter, P; Blazhev, A A; Voulot, D; Meot, V H; Simpson, G S; Georgiev, G P; Gaudefroy, L; Roig, O

    We propose to study the properties of odd-mass neutron-rich rubidium isotopes by the Coulomb-excitation technique, using the Miniball array coupled to the REX-ISOLDE facility. The results from similar measurements from the recent years (e.g. for the odd-mass and the odd-odd Cu isotopes, IS435) have shown the strong potential in such measurements for gaining information both for single-particle-like and collective states in exotic nuclei. Since there is practically no experimental information for excited states in the odd-mass Rb isotopes beyond $^{93}$Rb, the present study should be able to provide new data in a region of spherical ($^{93}$Rb and $^{95}$Rb) as well as well-deformed nuclei ($^{97}$Rb and $^{99}$Rb). Of particular interest is the rapid shape change that occurs when going from $^{95}$Rb (${\\varepsilon}_{2}$=0.06) to $^{97}$Rb (${\\varepsilon}_{2}$=0.3). These results should be of significant astrophysical interest as well, due to the close proximity of the r-process path.

  7. Structure studies on 82Kr by means of the multiple Coulomb excitation

    International Nuclear Information System (INIS)

    Bruessermann, S.

    1985-01-01

    With a 82 Kr beam of the energy 4.6 MeV per nucleon a 208 Pb target was irradiated in order to study the Coulomb excitation of 82 Kr. The experiment has been performed at the Society for Heavy Ion Research (GSI) in Darmstadt. The 82 Kr ions backscattered on the 208 Pb target were detected in a position-sensitive parallel-plate avalanche detector. The γ radiation of the excited 82 Kr particles was detected in 4 Ge(Li) detectors in coincidence with the particles. The spectra corrected regarding the Doppler shift contained 16 lines which permitted to determine by means of known mixing and branching ratios 22 electrical quadrupole transition matrix elements. The experimental excitation energies and the transition probabilities determined in this thesis are compared with different nuclear models, like the asymmetric rotator model, the rotational-vibrational model, the harmonic-oscillator model, the nuclear field theory, the SU(5) limit of the IBA-1, and the IBA-2 model. Thereby within the IBA-2 model a criterium for the symmetry of the wavefunction relative to the proton and neutron contributions is elaborated. Because of this criterium to the 2 1 + state a symmetric structure and to the 2 2 + ,3 states an asymmetric structure is assigned. (orig.) [de

  8. Plunger lifetime measurements in {sup 128}Xe using Coulomb excitation in inverse kinematics

    Energy Technology Data Exchange (ETDEWEB)

    Rother, Wolfram; Dewald, Alfred; Ilie, Gabriela; Pissulla, Thomas; Melon, Barbara; Jolie, Jan; Pascovici, Gheorghe; Zell, Karl-Oskar [IKP, Universitaet zu Koeln, Koeln (Germany); Julin, Rauno; Jones, Peter; Greenless, Paul; Rahkila, Panu; Scholey, Cath [JYFL, University of Jyvaeskylae, Jyvaeskylae (Finland); Harissopulos, Sotirios; Lagoyannis, Anastasios; Konstantinopoulos, T. [INP, N.C.S.R. ' ' Demokritos' ' , Athens (Greece); Grahn, Tuomas [JYFL, University of Jyvaeskylae, Jyvaeskylae (Finland)]|[Oliver Lodge Lab., University of Liverpool, Liverpool (United Kingdom); Balabanski, Dimiter [INRNE, Sofia (Bulgaria)

    2008-07-01

    We report on an experiment using Coulomb excitation in inverse kinematics in combination with the plunger technique for measuring lifetimes of excited states of the projectile. Aside from the investigation of E(2) features in {sup 128}Xe, the aim was to explore the special features of such experiments which are also suited to be used with radioactive beams. The measurement was performed at the JYFL with the Koeln coincidence plunger device and the JuroGam spectrometer using a {sup 128}Xe beam impinging on a {sup nat}Fe target at a beam energy of 525 MeV. Recoils were detected by means of 32 solar cells placed at extrem forward angles. Recoil-gated {gamma}-singles and {gamma}{gamma}-coincidences were measured at different target-degrader distances. Details of the experiment and first results are presented.

  9. Use of the Coulomb excitation by light and heavy ions for quantitative analysis

    International Nuclear Information System (INIS)

    Craciun, L.; Racolta, P. M.; Tripadus, V.; Dragulescu, E.; Serbanut, C.

    2001-01-01

    It is well known that in many cases thin layers with specific properties fulfil the same demands as former bulk materials and, although they seem to be more expensive, the general tendency has proven them to be cheaper. Therefore it might be a permanent task for physicists to develop methods, so far only applied in scientific laboratories, to a standard that might be feasible and economically justified to use them to a much larger extent. The reason for the very slow introduction of new analytical techniques is certainly the fear that instruments and apparatus used in basic research do not fulfil the standards of reliability, permanent availability and easy handling, which are important requirements for industrial applications. The knowledge of the slowing down of ions in crossing matter is of fundamental importance in methods of materials analysis using beams of charged atomic particles, Depth determination is based directly on the energy lost by the probing particles. The energy loss affects both quantitative and qualitative analyses. The physics of energy loss phenomena is very complex, involving many kinds of interactions between the projectile ion, target nuclei, and target electrons. Because of their significance in many fields of physics, these phenomena have been subject to intense studies since the beginning of the century. The theoretical treatment has been reviewed, among others, by Bohr (1948), Whaling (1958), Fano (1963), Jackson (1962,1975), Bichel (1970), Sigmund (1975), Ahlen (1980), Littmark and Ziegler (1980), Ziegler (1977, 1980), Ziegler et al. (1985). The experimental methods have been reviewed and investigated by, e.g., Chu (1979), Brauer (1987), Mertens (1987), Powers (1989). - Two well known phenomena can be used for the production of gamma-rays in bombardments with charged projectiles: a) nuclear reactions involving incident energies near and above the Coulomb barrier; in this case gamma-rays arise from the de-excitation of the product

  10. Interference of Coulomb and nuclear excitation in inelastic scattering of 20Ne from 40Ca

    International Nuclear Information System (INIS)

    Ratel, Guy.

    1976-01-01

    Angular distributions at 54 and 63MeV and excitation functions from 35 to 95MeV for the elastic and inelastic scattering of 20 Ne by 40 Ca have been measured. Experimental data for the inelastic scattering leading to the 20 Ne (2 + , 1.63MeV) state show a characteristic minimum for the angular distributions and excitation functions. This phenomenon was explained by an interference effect between Coulomb and nuclear excitation amplitudes with the DWBA and the coupled-channel formalism. The existence of this interference minimum could be explained only by assuming a nuclear deformation stronger than these obtained with light ion scattering. However a small shift between the experimental data and theoretical curves suggests that effects of a stronger complex coupling or nuclear reorientation due to the large quadrupole moment of 20 Ne must be included [fr

  11. Coulomb-nuclear interference (CNI) results of the collective quadrupolar excitations in odd and even Ru isotopes

    International Nuclear Information System (INIS)

    Rodrigues, C.L.; Rodrigues, M.R.D.; Borello-Lewin, T.; Horodynski-Matsushigue, L.B.; Duarte, J. L.M.; Hanninger, G.N.; Ukita, G.M.

    2004-01-01

    The study of the odd 99,101 Ru nuclei complements the investigation of the collectivity of the first quadrupolar excitations in 100,102,104 Ru. Angular distributions for the 99,101 Ru(d, d') reactions at 13 MeV were obtained in the Pelletron Laboratory using nuclear emulsion plates on the focal plane of the Enge spectrograph. A Coulomb- Nuclear Interference analysis employing DWBA-DOMP predictions with global optical potential parameters was applied to the excitation of states which could belong to the multiplet built on the first quadrupolar excitation of the core. In the analysis, three states were identified for each of the isotopes and associated, respectively, with adopted levels in the Nuclear Data Sheets Compilation of Jπ = 5=2 + , 7=2 + and 9=2 + . Through the comparison of experimental and predicted cross section angular distributions, the values of (δ L N ) 2 and of the ratio C = δ L C /δ L N were obtained. (author)

  12. Effect of the moment-of-inertia variation on Coulomb-nuclear interference in heavy ion scattering

    International Nuclear Information System (INIS)

    Bolotin, Yu.L.; Gonchar, V.Yu.; Inopin, E.V.; Chekanov, N.A.

    1987-01-01

    Effect of moment-of-inertia (MI) variation on probabilities of the Coulomb excitation of nucleus rotational states (RS) is investigated. The calculation is performed in the generalized quasiclassical approximation. Cillisions with an aimed parameter equal to 0 and recording of scattered ion at angles close to 180 deg were considered. Effect of MI dependence on angular momentum (AM) on the RS Coulomb excitation probability in the 86 Kr+ 238 U process at 400 MeV 86 Kr has been studied. For small AMs (I < 10), when the MI variation can be neglected, the Coulomb-nuclear interference leads to a marked shift of RS excitation probability maxima. However, with increasing transferred AM the convergence of probabilities conditioned with mutual compensation of phases shift related to the MI variation and Coulomb-nucleus interference, is noted. It is also noted that correct parameters of deformed nuclei extracted from experiments on the Coulomb excitation of high-spin states can be obtained only during simultaneous accountancy of both the Coulomb-nuclear interference and the MI variation of excited nuclei

  13. On rate-state and Coulomb failure models

    Science.gov (United States)

    Gomberg, J.; Beeler, N.; Blanpied, M.

    2000-01-01

    We examine the predictions of Coulomb failure stress and rate-state frictional models. We study the change in failure time (clock advance) Δt due to stress step perturbations (i.e., coseismic static stress increases) added to "background" stressing at a constant rate (i.e., tectonic loading) at time t0. The predictability of Δt implies a predictable change in seismicity rate r(t)/r0, testable using earthquake catalogs, where r0 is the constant rate resulting from tectonic stressing. Models of r(t)/r0, consistent with general properties of aftershock sequences, must predict an Omori law seismicity decay rate, a sequence duration that is less than a few percent of the mainshock cycle time and a return directly to the background rate. A Coulomb model requires that a fault remains locked during loading, that failure occur instantaneously, and that Δt is independent of t0. These characteristics imply an instantaneous infinite seismicity rate increase of zero duration. Numerical calculations of r(t)/r0 for different state evolution laws show that aftershocks occur on faults extremely close to failure at the mainshock origin time, that these faults must be "Coulomb-like," and that the slip evolution law can be precluded. Real aftershock population characteristics also may constrain rate-state constitutive parameters; a may be lower than laboratory values, the stiffness may be high, and/or normal stress may be lower than lithostatic. We also compare Coulomb and rate-state models theoretically. Rate-state model fault behavior becomes more Coulomb-like as constitutive parameter a decreases relative to parameter b. This is because the slip initially decelerates, representing an initial healing of fault contacts. The deceleration is more pronounced for smaller a, more closely simulating a locked fault. Even when the rate-state Δt has Coulomb characteristics, its magnitude may differ by some constant dependent on b. In this case, a rate-state model behaves like a modified

  14. Resonant Coulomb excitation of atomic nuclei propagating through a crystal in the channeling mode

    International Nuclear Information System (INIS)

    Stepanov, A.V.

    1996-01-01

    The Coulomb-excitation total cross section and the distribution of decay products originating from a resonant state of a nucleus interacting with a crystal lattice has been calculated for the case of a single inelastic collision (with respect to internal degrees of freedom in a nucleus). These observables have been expressed in terms of time-dependent correlators which describe thermal oscillations of lattice nuclei and the motion of the center of mass of a nucleus propagating across a crystal target in the channelling mode. An expression generalizing the spectrum of equivalent photons calculated by the Weizsaecker-Williams method is given

  15. Finite pt contribution to relativistic Coulomb excitation: A possible explanation for the clean fission puzzle

    International Nuclear Information System (INIS)

    Galetti, D.; Kodama, T.; Nemes, M.C.

    1986-10-01

    The quantum relativistic Coulomb excitation process including reccil effects is studied in the plane wave Born approximation. Quantum and relativistic recoil effects allow for relatively large transverse momentum transfers, usually neglected. This specific feature is shown to modify the angular distribution of Coulomb induced fission fragmentation in an essential manner. In contrast with usual treatments it is found that these results compare favourably with recent data. (Authors) [pt

  16. Coulomb-nuclear interference (CNI) results of the collective quadrupolar excitations in odd and even Ru isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, C.L.; Rodrigues, M.R.D.; Borello-Lewin, T.; Horodynski-Matsushigue, L.B.; Duarte, J. L.M.; Hanninger, G.N. [Sao Paulo Univ., SP (Brazil). Inst. de Fisica; Ukita, G.M. [Universidade de Santo Amaro, SP (Brazil). Faculdade de Psicologia

    2004-09-15

    The study of the odd {sup 99,101}Ru nuclei complements the investigation of the collectivity of the first quadrupolar excitations in {sup 100,102,104}Ru. Angular distributions for the {sup 99,101}Ru(d, d') reactions at 13 MeV were obtained in the Pelletron Laboratory using nuclear emulsion plates on the focal plane of the Enge spectrograph. A Coulomb- Nuclear Interference analysis employing DWBA-DOMP predictions with global optical potential parameters was applied to the excitation of states which could belong to the multiplet built on the first quadrupolar excitation of the core. In the analysis, three states were identified for each of the isotopes and associated, respectively, with adopted levels in the Nuclear Data Sheets Compilation of J{pi} = 5=2{sup +}, 7=2{sup +} and 9=2{sup +}. Through the comparison of experimental and predicted cross section angular distributions, the values of ({delta}{sup L}{sub N}){sup 2} and of the ratio C = {delta}{sub L}{sup C} /{delta}{sub L}{sup N} were obtained. (author)

  17. Coulomb states in atoms and solids

    International Nuclear Information System (INIS)

    Ortalano, D.M.

    1988-05-01

    In this dissertation, an empirical quantum defect approach to describe the valence excitons of the rare gas solids is developed. These Coulomb states are of s-symmetry and form a hydrogen-like series which converges to the bottom of the lowest conduction band. A non-zero quantum defect is found for all of the excitons of neon, argon and xenon. For these systems, then, there exists, in addition to the screened Coulombic component, a non-Coulombic component to the total exciton binding energy. The Wannier formalism is, therefore, inappropriate for the excitons of Ne, Ar and Xe. From the sign of the quantum defect, the non-Coulombic potential is repulsive for Ne and Ar, attractive for Xe, and nearly zero for Kr. This is opposite to that for the Rydberg states of the corresponding rare gas atoms, where the non-Coulombic potential between the electron and the cation is attractive for all of the atoms. The excitons then, are not simply perturbed Rydberg states of the corresponding rare gas atoms (i.e., the excitons do not possess atomic parentage). Interatomic term value/band gap energy correlations and reduced term value/reduced band gap correlations were performed. These correlations were exploited to provide further evidence against both the Wannier formalism and the atomic parentage view point. From these correlations, it was also discovered that the non-Coulombic potential varies smoothly across the valence isoelectronic series of solids, and that it becomes more attractive (or less repulsive) in going from neon to xenon. In order to address the atomic parentage controversy, it was necessary to compare the excitons to the low-n Rydberg states of the rare gas atoms. A review of the quantum defect description of the atomic Rydberg states is, therefore, presented. Also, Rydberg term value/ionization energy correlations are discussed and compared with the analogous exciton correlations. 7 refs., 10 figs., 5 tabs

  18. Radioactive beam EXperiments at ISOLDE : Coulomb excitation and neutron transfer reactions of exotic nuclei.

    CERN Multimedia

    Kugler, E; Ratzinger, U; Wenander, F J C

    2002-01-01

    % IS347 \\\\ \\\\We propose to perform a pilot experiment to study very neutron rich (A<32) Na-Mg and (A<52) K-Ca isotopes in the region around the neutron shell closures of N=20 and N=28 after Coulomb excitation and neutron transfer, and to demonstrate highly efficient and cost-effective ways to bunch, charge-state breed and accelerate already existing mass-separated singly-charged radioactive ion beams. \\\\ \\\\To do this we plan to accelerate the ISOLDE beams up to 2~MeV/u by means of a novel acceleration scheme and to install an efficient $\\gamma$-ray array for low-multiplicity events around the target position.

  19. Excitation of autoionizing states of helium by 100 keV proton impact: theory and experiment

    International Nuclear Information System (INIS)

    Godunov, A.L.; Moretto-Capelle, P.; Bordenave-Montesquieu, D.; Benhenni, M.; Bordenave-Montesquieu, A.

    1997-01-01

    A joint theoretical and experimental study of the excitation of the autoionizing (2s 2 ) 1 S, (2p 2 ) 1 D and (2s2p) 1 P states of helium by 100 keV proton impact is presented for the first time. The role of the three-body Coulomb interaction in the final state between the ejected electron, the scattered proton and the recoil helium ion is emphasized. Calculations have been carried out with inclusion of the three-body Coulomb interaction and within an expansion of a two-electron excitation amplitude in powers of projectile-target interaction up to the second order. A new parametrization is proposed to describe resonance profiles distorted by the Coulomb interaction in the final state (CIFS). New high-resolution (up to 68 meV) measurements of electron emission spectra made it possible to resolve the near-lying (2p 2 ) 1 D and (2s2p) 1 P resonances and reveal an evident distortion of the resonance profiles by CIFS for forward electron ejection angles below 40 o . (author)

  20. Determination of the B(E3,0$^{+}$ $\\rightarrow$ 3$^{-}$) strength in the octupole correlated nuclei $^{142,144}$Ba using Coulomb excitation

    CERN Multimedia

    We propose to exploit the unique capability of ISOLDE to provide intense post-accelerated $^{142}$Ba and $^{144}$Ba ion beams from the HIE-ISOLDE facility to enable the Coulomb excitation of the first 3$^-$ state in these nuclei. By measuring the $\\gamma$-ray yields of the E1 decays from the 3$^-$ state using the MINIBALL array, we can obtain the interesting transition matrix element. The results will give quantitative information about octupole correlations in these nuclei.

  1. Study of the N=40 shell by using Coulomb excitation; Etude par excitation coulombienne de la fermeture de couche N=40

    Energy Technology Data Exchange (ETDEWEB)

    Leenhardt, St

    2000-01-01

    Two Coulomb excitation experiments on neutron rich exotic nuclei have been performed at GANIL. They allowed the measurement of the reduced transition probability B(E2) (from ground state to first excited state) of some nuclei around N = 40. This number, 40, is a half-magic number in the shell model. For nuclei with an important neutron excess, it is predicted that the shell closure is stronger at N = 40. The B(E2) is a good tool for testing this growing. We have measured, by using the LISE3 spectrometer and a {gamma} multidetector, B(E2) of {sup 68}Ni, {sup 66}Ni and {sup 72}Zn, unknown till now. We have used for the first time segmented germanium 'clovers' detector, for photon detection (v/c{approx}0.3). Results confirm the strong shell effect for {sup 68}Ni. Indeed {sup 68}Ni was shown to be the Nickel isotope with the lowest value of B(E2), and hence the most rigid isotope. Nevertheless it seems that the shell effect at N = 40 decreases rapidly, for other isotopes very close to {sup 68}Ni(Z = 28) and N = 40). (authors)

  2. Determination of the B(E3;0$^+\\!\\rightarrow$ 3$^{-}$) strength in the octupole correlated nucleus $^{144}$Ba using Coulomb excitation

    CERN Multimedia

    We propose to exploit the unique capability of ISOLDE to provide intense post-accelerated $^{144}$Ba ion beams from the REX facility to enable the Coulomb excitation of the first 3$^{-}$ state in this nucleus. By measuring the $\\gamma$-ray yields of the E1 decay connecting the 3$^{-}$ and 2$^{+}$ states using the MINIBALL array, we can obtain the interesting transition matrix element. The result will give quantitative information about octupole correlations in this nucleus. We require 27 shifts to fulfill the aims of the experiment.

  3. Obtaining Empirical Validation of Shape-Coexistence in the Mass 70 Region: Coulomb Excitation of a Radioactive Beam of $^{70}$Se

    CERN Multimedia

    Andreoiu, C; Paul, E S; Czosnyka, T; Hammond, N

    2002-01-01

    We propose to study the Coulomb excitation of a radioactive beam of $^{70}$Se at 2.2 MeV/u obtained from the REX-ISOLDE facility in order to determine the sign of the quadrupole moment and, hence, the sign of the quadrupole deformation. Calculations suggest a 33~\\% sensitivity in Coulomb excitation yield for a nickel target depending on whether the nuclear shape is oblate or prolate. Such a determination would provide compelling evidence for the presence of oblate shapes in the vicinity of N=Z=34.

  4. Excitation of autoionizing states of helium by 100 keV proton impact: theory and experiment

    Energy Technology Data Exchange (ETDEWEB)

    Godunov, A.L.; Moretto-Capelle, P.; Bordenave-Montesquieu, D.; Benhenni, M.; Bordenave-Montesquieu, A. [Universite Paul Sabatier, Toulouse (France). Laboratoire Collisions, Agregats, Reactivite; Schipakov, V.A. [Troitsk Institute for Innovation and Fusion Research, Moscow (Russian Federation)

    1997-12-14

    A joint theoretical and experimental study of the excitation of the autoionizing (2s{sup 2}){sup 1}S, (2p{sup 2}){sup 1}D and (2s2p){sup 1}P states of helium by 100 keV proton impact is presented for the first time. The role of the three-body Coulomb interaction in the final state between the ejected electron, the scattered proton and the recoil helium ion is emphasized. Calculations have been carried out with inclusion of the three-body Coulomb interaction and within an expansion of a two-electron excitation amplitude in powers of projectile-target interaction up to the second order. A new parametrization is proposed to describe resonance profiles distorted by the Coulomb interaction in the final state (CIFS). New high-resolution (up to 68 meV) measurements of electron emission spectra made it possible to resolve the near-lying (2p{sup 2}){sup 1}D and (2s2p){sup 1}P resonances and reveal an evident distortion of the resonance profiles by CIFS for forward electron ejection angles below 40{sup o}. (author).

  5. Core polarization and Coulomb displacement energies

    International Nuclear Information System (INIS)

    Shlomo, S.; Love, W.G.

    1982-01-01

    The contributions of core polarization terms (other than the Auerbach-Kahana-Weneser (AKW) effect) to Coulomb displacement energies of mirror nuclei near A = 16 and A = 40 are examined within the particle-vibration coupling model. The parameters of the model are determined using updated data on the locations and strengths of multipole core excitations. In the absence of relevant data an energy-weighted sum rule (EWSR) is exploited. Taking into account multipole excitations up to L = 5 and subtracting the contributions which are due to short-range correlations, significant contributions (1-3%) to ΔEsub(c) are found. These corrections arise from particle coupling to low-lying collective states (long-range correlations). The implications of these results on the Coulomb energy problem are discussed. (Auth.)

  6. Investigation of beam purity after in-trap decay and Coulomb excitation of $^{62}$Mn-$^{62}$Fe

    CERN Multimedia

    Clement, E; Gernhaeuser, R A; Diriken, J V J; Huyse, M L

    2008-01-01

    The in-trap decay of short lived radioactive ions is not well understood. This poses a problem for Coulomb excitation experiments at MINIBALL, where the normalization of the experiment depends strongly on observed secondary target excitation, which in turn strongly depends on the knowledge of the beam composition. For pure ISOLDE beams of short lived isotopes, the in-trap decay becomes important since a large fraction of the beam is transformed in unwanted daughter isotopes. In this proposal we intend to quantify the production of these daughter products in the REXTRAP accurately by making use of the short lived isotopes $^{61,62}$Mn and the newly installed Bragg ionization chamber at the end of the REX linear accelerator. Apart from the technical interest, the A=62 beam provides as well a good physics case, concerning the development of collectivity in neutron-rich Fe isotopes. Coulomb excitation, utilizing the standard MINIBALL setup, is proposed on both A=62 Mn and Fe. The Fe beam would be the first post-a...

  7. Bound and resonant states in Coulomb-like potentials

    International Nuclear Information System (INIS)

    Papp, Z.

    1985-12-01

    The potential separable expansion method was generalized for calculating bound and resonant states in Coulomb-like potentials. The complete set of Coulomb-Sturmian functions was taken as the basis to expand the short-range potential. On this basis the matrix elements of the Coulomb-Green functions were given in closed form as functions of the (complex) energy. The feasibility of the method is demonstrated by a numerical example. (author)

  8. Electron impact excitation of positive ions calculated in the Coulomb-Born approximation

    International Nuclear Information System (INIS)

    Nakazaki, Shinobu; Hashino, Tasuke

    1979-08-01

    Theoretical results on the electron impact excitation of positive ions are surveyed through the end of 1978. As a guide to the available data, a list of references is made. The list shows ion species, transitions, energy range and methods of calculation for the respective data. Based on the literature survey, the validity of the Coulomb-Born approximation is investigated. Comparisons with the results of the close-coupling and the distorted-wave methods are briefly summarized. (author)

  9. A new recoil distance technique using low energy coulomb excitation in inverse kinematics

    Energy Technology Data Exchange (ETDEWEB)

    Rother, W., E-mail: wolfram.rother@googlemail.com [Institut fuer Kernphysik der Universitaet zu Koeln, Zuelpicher Str. 77, D-50937 Koeln (Germany); Dewald, A.; Pascovici, G.; Fransen, C.; Friessner, G.; Hackstein, M. [Institut fuer Kernphysik der Universitaet zu Koeln, Zuelpicher Str. 77, D-50937 Koeln (Germany); Ilie, G. [Wright Nuclear Structure Laboratory, Yale University, New Haven, CT 06520 (United States); National Institute of Physics and Nuclear Engineering, P.O. Box MG-6, Bucharest-Magurele (Romania); Iwasaki, H. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824 (United States); Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States); Jolie, J. [Institut fuer Kernphysik der Universitaet zu Koeln, Zuelpicher Str. 77, D-50937 Koeln (Germany); Melon, B. [Dipartimento di Fisica, Universita di Firenze and INFN Sezione di Firenze, Sesto Fiorentino (Firenze) I-50019 (Italy); Petkov, P. [Institut fuer Kernphysik der Universitaet zu Koeln, Zuelpicher Str. 77, D-50937 Koeln (Germany); INRNE-BAS, Sofia (Bulgaria); Pfeiffer, M. [Institut fuer Kernphysik der Universitaet zu Koeln, Zuelpicher Str. 77, D-50937 Koeln (Germany); Pissulla, Th. [Institut fuer Kernphysik der Universitaet zu Koeln, Zuelpicher Str. 77, D-50937 Koeln (Germany); Bundesumweltministerium, Robert-Schuman-Platz 3, D - 53175 Bonn (Germany); Zell, K.-O. [Institut fuer Kernphysik der Universitaet zu Koeln, Zuelpicher Str. 77, D-50937 Koeln (Germany); Jakobsson, U.; Julin, R.; Jones, P.; Ketelhut, S.; Nieminen, P.; Peura, P. [Department of Physics, University of Jyvaeskylae, P.O. Box 35, FI-40014 (Finland); and others

    2011-10-21

    We report on the first experiment combining the Recoil Distance Doppler Shift technique and multistep Coulomb excitation in inverse kinematics at beam energies of 3-10 A MeV. The setup involves a standard plunger device equipped with a degrader foil instead of the normally used stopper foil. An array of particle detectors is positioned at forward angles to detect target-like recoil nuclei which are used as a trigger to discriminate against excitations in the degrader foil. The method has been successfully applied to measure lifetimes in {sup 128}Xe and is suited to be a useful tool for experiments with radioactive ion beams.

  10. Generalized coherent states for the Coulomb problem in one dimension

    International Nuclear Information System (INIS)

    Nouri, S.

    2002-01-01

    A set of generalized coherent states for the one-dimensional Coulomb problem in coordinate representation is constructed. At first, we obtain a mapping for proper transformation of the one-dimensional Coulomb problem into a nonrotating four-dimensional isotropic harmonic oscillator in the hyperspherical space, and the generalized coherent states for the one-dimensional Coulomb problem is then obtained in exact closed form. This exactly soluble model can provide an adequate means for a quantum coherency description of the Coulomb problem in one dimension, sample for coherent aspects of the exciton model in one-dimension example in high-temperature superconductivity, semiconductors, and polymers. Also, it can be useful for investigating the coherent scattering of the Coulomb particles in one dimension

  11. Mirror symmetry and Coulomb effects in light N ≅ Z nuclei

    International Nuclear Information System (INIS)

    Bentley, M.A.; Williams, S.J.; Joss, D.T.

    2002-01-01

    Some latest results from gamma-ray spectroscopic studies of high spin states of isobaric multiplets are presented. An experimental programme is underway to examine exited states of isobaric multiplets of total isospin T 1/2 and T = 1 and the comparison of energies of excited states can be interpreted in terms of Coulomb effects. Through a systematic study of these Coulomb effects, and through examination of the calculated Coulomb energies from full pf-shell model calculations, it is now becoming clear that measurement of Coulomb energies can yield very detailed information on the evolution of nuclear structure phenomena as a function of energy and angular momentum. In this contribution, latest results of studies of isobaric analogue states at high spin in the A = 50, 51 and 53 systems are presented. (author)

  12. Evolution of collectivity in the 78Ni region: Coulomb excitation of 74Ni at intermediate energies.

    Directory of Open Access Journals (Sweden)

    Marchi T.

    2014-03-01

    Full Text Available The study of the collective properties of nuclear excitations far from stability provides information about the shell structure at extreme conditions. Spectroscopic observables such as the energy or the transition probabilities of the lowest states, in nuclei with large neutron excess, allow to probe the density and isospin dependence of the effective interaction. Indeed, it was recently shown that tensor and three-body forces play an important role in breaking and creating magic numbers. Emblematic is the case of the evolution of the Ni isotopic chain where several features showed up moving from the most neutron rich stable isotope (64Ni towards the 78Ni nucleus where the large neutron excess coincides with a double shell closure. In this framework, we have recently performed an experiment with the goal to extract the B(E2; 0+ → 2+ value for the 74Ni nucleus in an intermediate-energy Coulomb excitation experiment: preliminary results are discussed.

  13. Coulomb Final State Interactions for Gaussian Wave Packets

    CERN Document Server

    Wiedemann, Urs Achim; Heinz, Ulrich W

    1999-01-01

    Two-particle like-sign and unlike-sign correlations including Coulomb final state interactions are calculated for Gaussian wave packets emitted from a Gaussian source. We show that the width of the wave packets can be fully absorbed into the spatial and momentum space widths of an effective emission function for plane wave states, and that Coulomb final state interaction effects are sensitive only to the latter, but not to the wave packet width itself. Results from analytical and numerical calculations are compared with recently published work by other authors.

  14. Onset of collectivity in neutron-rich Sr and Kr isotopes: Prompt spectroscopy after Coulomb excitation at REX-ISOLDE, CERN

    Directory of Open Access Journals (Sweden)

    Clément E.

    2013-12-01

    Full Text Available A rapid onset of quadrupole deformation is known to occur around the neutron number 60 in the neutron-rich Zr and Sr isotopes. This shape change has made the neutron-rich A = 100 region an active area of experimental and theoretical studies for many decades now. We report in this contribution new experimental results in the neutron rich 96,98Sr investigated by safe Coulomb excitation of radioactive beams at the REX-ISOLDE facility, CERN. Reduced transition probabilities and spectroscopic quadrupole moments have been extracted from the differential Coulomb excitation cross section supporting the scenario of shape coexistence/change at N = 60. Future perspectives are presented including the recent experimental campaign performed at ILL-Grenoble.

  15. First Results with TIGRESS and Accelerated Radioactive Ion Beams from ISAC: Coulomb Excitation of 20,21,29Na

    Science.gov (United States)

    Schumaker, M. A.; Hurst, A. M.; Svensson, C. E.; Wu, C. Y.; Becker, J. A.; Cline, D.; Hackman, G.; Pearson, C. J.; Stoyer, M. A.; Andreyev, A.; Austin, R. A. E.; Ball, G. C.; Bandyopadhyay, D.; Barton, C. J.; Boston, A. J.; Boston, H. C.; Buchmann, L.; Churchman, R.; Cifarelli, F.; Colosimo, S. J.; Cooper, R. J.; Cross, D. S.; Dashdorj, D.; Demand, G. A.; Dimmock, M. R.; Djongolov, M.; Drake, T. E.; Finlay, P.; Gallant, A. T.; Garrett, P. E.; Gray-Jones, C.; Green, K. L.; Grint, A. N.; Grinyer, G. F.; Harkness, L. J.; Hayes, A. B.; Kanungo, R.; Leach, K. G.; Kulp, W. D.; Lisetskiy, A. F.; Lee, G.; Lloyd, S.; Maharaj, R.; Martin, J.-P.; Millar, B. A.; Moisan, F.; Morton, A. C.; Mythili, S.; Nelson, L.; Newman, O.; Nolan, P. J.; Orce, J. N.; Oxley, D. C.; Padilla-Rodal, E.; Phillips, A. A.; Porter-Peden, M.; Ressler, J. J.; Rigby, S. V.; Roy, R.; Ruiz, C.; Sarazin, F.; Scraggs, D. P.; Sumithrarachchi, C. S.; Triambak, S.; Waddington, J. C.; Walker, P. M.; Wan, J.; Whitbeck, A.; Williams, S. J.; Wong, J.; Wood, J. L.

    2009-03-01

    The TRIUMF-ISAC Gamma-Ray Escape Suppressed Spectrometer (TIGRESS) is a state-of-the-art γ-ray spectrometer being constructed at the ISAC-II radioactive ion beam facility at TRIUMF. TIGRESS will be comprised of twelve 32-fold segmented high-purity germanium (HPGe) clover-type γ-ray detectors, with BGO/CsI(Tl) Compton-suppression shields, and is currently operational at ISAC-II in an early-implementation configuration of six detectors. Results have been obtained for the first experiments performed using TIGRESS, which examined the A = 20, 21, and 29 isotopes of Na by Coulomb excitation.

  16. Generalized ladder operators for the Dirac-Coulomb problem via SUSY QM

    International Nuclear Information System (INIS)

    Rodrigues, R. de Lima; Universidade Federal de Campina Grande, PB

    2003-12-01

    The supersymmetry in quantum mechanics and shape invariance condition are applied as an algebraic method to solving the Dirac-Coulomb problem. The ground state and the excited states are investigated via new generalized ladder operators. (author)

  17. Static quadrupole moment of the first excited state of 24Mg

    International Nuclear Information System (INIS)

    Fewell, M.P.; Hinds, S.; Kean, D.C.; Zabel, T.H.

    1979-01-01

    The static quadrupole moment Qsub(2+) and the B(E2;0 + → 2 + ) value for the first excited state of 24 Mg have been determined using the reorientation effect in Coulomb excitation. Surface barrier detectors at 90 0 and 172 0 were used to detect 24 Mg ions scattered from 208 Pb. It is found that Qsub(2+) = -18.1 +- 1.3 e.fm 2 , suggesting that, contrary to most previous experimental evidence, the quadrupole moment is in agreement with theoretical predictions. For B(E2;0 + → 2 + ) the value 443 +- 24 e 2 . fm 4 was obtained

  18. Dynamic polarization by coulomb excitation in the closed formalism for heavy ion scattering

    International Nuclear Information System (INIS)

    Frahn, W.E.; Hill, T.F.

    1978-01-01

    We present a closed-form treatment of the effects of dynamic polarization by Coulomb excitation on the elastic scattering of deformed heavy ions. We assume that this interaction can be represented by an absorptive polarization potential. The relatively long range of this potential entails a relatively slow variation of the associated reflection function in l-space. This feature leads to a simple generalization of the closed formula derived previously for the elastic scattering amplitude of spherical heavy nuclei. We use both the polarization potential of Love et al. and the recent improved potential of Baltz et al. to derive explicit expressions for the associated reflection functions in a Coulomb-distorted eikonal approximation. As an example we analyze the elastic scattering of 90-MeV 18 O ions by 184 W and show that both results give a quantitative description of the data. (orig.) [de

  19. Excitation of giant resonances in heavy ion collisions

    International Nuclear Information System (INIS)

    Kuehn, W.

    1991-01-01

    Introduction: What are Giant Resonances? General Features of Giant Resonances, Macroscopic Description and Classification, Basic Excitation Mechanisms, Decay Modes, Giant Resonances Built on Excited States, Relativistic Coulomb Excitation of Giant Resonances, Experimental Situation. (orig.)

  20. Contribution to the study of collective states of heavy nuclei by means of coulomb excitation; Contribution a l'etude des etats collectifs des noyaux lourds par excitation coulombienne

    Energy Technology Data Exchange (ETDEWEB)

    Barloutaud, R [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1958-06-15

    The following nuclei were excited by protons of 5 MeV maximum energy: {sup 182}W - {sup 184}W - {sup 186}W - {sup 186}Os - {sup 188}Os - {sup 189}Os - {sup 190}Os - {sup 192}Os - {sup 194}Pt - {sup 196}Pt - {sup 198}Pt - {sup 198}Hg - {sup 200}Hg - {sup 202}Hg - {sup 204}Hg - {sup 206}Pb. The reduced probabilities of the various transitions were deduced from the coulomb excitation cross-section measurements. For some even-even nuclei two 2 + levels were excited. The properties of the excited levels are interpreted in terms of the collective model. (author) [French] Au moyen de protons d'energie inferieure a 5 MeV, l'excitation coulombienne des noyaux suivants a ete etudiee: {sup 182}W - {sup 184}W - {sup 186}W - {sup 186}Os - {sup 188}Os - {sup 189}Os - {sup 190}Os - {sup 192}Os - {sup 194}Pt - {sup 196}Pt - {sup 198}Pt - {sup 198}Hg - {sup 200}Hg - {sup 202}Hg - {sup 204}Hg - {sup 206}Pb. La mesure de la section efficace d'excitation coulombienne a permis de deduire les -probabilites reduites des diverses transitions observees. Dans certains noyaux pair-pair, deux niveaux de caractere 2 + ont ete excites. L'interpretation de ces niveaux en termes de niveaux de rotation et de niveaux de vibration a l'aide du modele collectif est discutee. En particulier, la variation des proprietes de ces niveaux avec la deformation nucleaire permet de fixer des limites a la validite des diverses hypotheses entrant dans le modele collectif. (auteur)

  1. Influences of temperature on asymmetric quantum dot qubit in Coulombic impunity potential

    Science.gov (United States)

    Chen, Y.-J.; Song, H.-T.; Xiao, J.-L.

    2018-05-01

    Using the variational method of the Pekar-type, we study the influences of the temperature on the asymmetric quantum dot (QD) qubit in the Coulombic impunity potential. Then we derive the numerical results and formulate the derivative relationships of the electron probability density and the electron oscillation period in the superposition state of the ground state and the first-excited state with the electron-phonon coupling constant, the Coulombic impurity potential, the transverse and longitudinal confinement strengths at different temperatures, respectively.

  2. Is the ground state of Yang-Mills theory Coulombic?

    Science.gov (United States)

    Heinzl, T.; Ilderton, A.; Langfeld, K.; Lavelle, M.; Lutz, W.; McMullan, D.

    2008-08-01

    We study trial states modelling the heavy quark-antiquark ground state in SU(2) Yang-Mills theory. A state describing the flux tube between quarks as a thin string of glue is found to be a poor description of the continuum ground state; the infinitesimal thickness of the string leads to UV artifacts which suppress the overlap with the ground state. Contrastingly, a state which surrounds the quarks with non-Abelian Coulomb fields is found to have a good overlap with the ground state for all charge separations. In fact, the overlap increases as the lattice regulator is removed. This opens up the possibility that the Coulomb state is the true ground state in the continuum limit.

  3. Coulomb excitation $^{74}$Zn-$^{80}$Zn (N=50): probing the validity of shell-model descriptions around $^{78}$Ni

    CERN Multimedia

    A study of the evolution of the nuclear structure along the zinc isotopic chain close to the doubly magic nucleus $^{78}$Ni is proposed to probe recent shell-model calculations in this area of the nuclear chart. Excitation energies and connecting B(E2) values will be measured through multiple Coulomb excitation experiment with laser ionized purified beams of $^{74-80}$Zn from HIE ISOLDE. The current proposal request 30 shifts.

  4. Two-dimensional QCD in the Coulomb gauge

    International Nuclear Information System (INIS)

    Kalashnikova, Yu.S.; Nefed'ev, A.V.

    2002-01-01

    Various aspects of the 't Hooft model for two-dimensional QCD in the limit of infinite number of colours in the Coulomb gauge are discussed. The properties of mesonic excitations are studied, with special emphasis on the pion. Attention is paid to the dual role of the pion. which, while a genuine qq-bar state, is a Goldstone boson of two-dimensional QCD as well. In particular, the validity of the soft-pion theorems is demonstrated. It is shown that the Coulomb gauge is the most suitable choice for the study of hadronic observables involving pions [ru

  5. On the sequentiality of the multiple Coulomb-excitation process

    International Nuclear Information System (INIS)

    Dannhaeuser, G.; Boer, J. de

    1978-01-01

    This paper describes the results of 'computer experiments' illustrating the meaning of a new concept called 'sequentiality'. This concept applies to processes in which the excitation of a given state is mainly accomplished by a large multiple of steps, and it deals with the question as to what extent a transition close to the ground state occurs before one between the highest excited states. (orig.) [de

  6. Determination of minimum impact parameter by modified touching spheres schemes for intermediate energy Coulomb excitation experiments

    International Nuclear Information System (INIS)

    Kumar, Rajiv; Sharma, Shagun; Singh, Pradeep; Kharab, Rajesh

    2016-01-01

    The energy-independent touching spheres schemes commonly used for the determination of the safe minimum value of the impact parameter for Coulomb excitation experiments are modified through the inclusion of an energy-dependent term. The touching spheres+3fm scheme after modification emerges out to be the best one while touching spheres+4fm scheme is found to be better in its unmodified form. (orig.)

  7. On analytical solutions to the problem of the Coulomb and confining potentials

    International Nuclear Information System (INIS)

    Dineykhan, M.; Nazmitdinov, R.G.

    1997-01-01

    The oscillator representation method is presented and applied to calculate the energy spectrum of the superposition of the Coulomb and the power-law potentials, the Coulomb and the Yukawa potentials. The method provides an efficient way to obtain analytical results for arbitrary set of parameters of the considered potentials. The energies of ground and excited states of a quantum system are in good agreement with the exact results

  8. The Coulomb gap and low energy statistics for Coulomb glasses

    International Nuclear Information System (INIS)

    Glatz, Andreas; Vinokur, Valerii M; Bergli, Joakim; Kirkengen, Martin; Galperin, Yuri M

    2008-01-01

    We study the statistics of local energy minima in the configuration space of two-dimensional lattice Coulomb glasses with site disorder and the behavior of the Coulomb gap depending on the strength of random site energies. At intermediate disorder, i.e., when the typical strength of the disorder is of the same order as the nearest-neighbor Coulomb energy, the high energy tail of the distribution of the local minima is exponential. We furthermore analyze the structure of the local minima and show that most sites of the system have the same occupation numbers in all of these states. The density of states (DOS) shows a transition from the crystalline state at zero disorder (with a hard gap) to an intermediate, probably glassy state with a Coulomb gap. We analyze this Coulomb gap in some detail and show that the DOS deviates slightly from the traditional linear behavior in 2D. For finite systems these intermediate Coulomb gap states disappear for large disorder strengths and only a random localized state in which all electrons are in the minima of the random potential exists. Dedication: This paper is dedicated to Thomas Nattermann, our dearest friend, brilliant colleague, and outstanding teacher

  9. Computational assignment of redox states to Coulomb blockade diamonds.

    Science.gov (United States)

    Olsen, Stine T; Arcisauskaite, Vaida; Hansen, Thorsten; Kongsted, Jacob; Mikkelsen, Kurt V

    2014-09-07

    With the advent of molecular transistors, electrochemistry can now be studied at the single-molecule level. Experimentally, the redox chemistry of the molecule manifests itself as features in the observed Coulomb blockade diamonds. We present a simple theoretical method for explicit construction of the Coulomb blockade diamonds of a molecule. A combined quantum mechanical/molecular mechanical method is invoked to calculate redox energies and polarizabilities of the molecules, including the screening effect of the metal leads. This direct approach circumvents the need for explicit modelling of the gate electrode. From the calculated parameters the Coulomb blockade diamonds are constructed using simple theory. We offer a theoretical tool for assignment of Coulomb blockade diamonds to specific redox states in particular, and a study of chemical details in the diamonds in general. With the ongoing experimental developments in molecular transistor experiments, our tool could find use in molecular electronics, electrochemistry, and electrocatalysis.

  10. Three-body Coulomb systems using generalized angular-momentum S states

    Science.gov (United States)

    Whitten, R. C.; Sims, J. S.

    1974-01-01

    An expansion of the three-body Coulomb potential in generalized angular-momentum eigenfunctions developed earlier by one of the authors is used to compute energy eigenvalues and eigenfunctions of bound S states of three-body Coulomb systems. The results for He, H(-), e(-)e(+)e(-), and pmu(-)p are compared with the results of other computational approaches.

  11. Plane-Wave Implementation and Performance of à-la-Carte Coulomb-Attenuated Exchange-Correlation Functionals for Predicting Optical Excitation Energies in Some Notorious Cases.

    Science.gov (United States)

    Bircher, Martin P; Rothlisberger, Ursula

    2018-06-12

    Linear-response time-dependent density functional theory (LR-TD-DFT) has become a valuable tool in the calculation of excited states of molecules of various sizes. However, standard generalized-gradient approximation and hybrid exchange-correlation (xc) functionals often fail to correctly predict charge-transfer (CT) excitations with low orbital overlap, thus limiting the scope of the method. The Coulomb-attenuation method (CAM) in the form of the CAM-B3LYP functional has been shown to reliably remedy this problem in many CT systems, making accurate predictions possible. However, in spite of a rather consistent performance across different orbital overlap regimes, some pitfalls remain. Here, we present a fully flexible and adaptable implementation of the CAM for Γ-point calculations within the plane-wave pseudopotential molecular dynamics package CPMD and explore how customized xc functionals can improve the optical spectra of some notorious cases. We find that results obtained using plane waves agree well with those from all-electron calculations employing atom-centered bases, and that it is possible to construct a new Coulomb-attenuated xc functional based on simple considerations. We show that such a functional is able to outperform CAM-B3LYP in some cases, while retaining similar accuracy in systems where CAM-B3LYP performs well.

  12. Shape isomerism and shape coexistence effects on the Coulomb energy differences in the N=Z nucleus 66As and neighboring T=1 multiplets

    Science.gov (United States)

    de Angelis, G.; Wiedemann, K. T.; Martinez, T.; Orlandi, R.; Petrovici, A.; Sahin, E.; Valiente-Dobón, J. J.; Tonev, D.; Lunardi, S.; Nara Singh, B. S.; Wadsworth, R.; Gadea, A.; Kaneko, K.; Bizzeti, P. G.; Bizzeti-Sona, A. M.; Blank, B.; Bracco, A.; Carpenter, M. P.; Chiara, C. J.; Farnea, E.; Gottardo, A.; Greene, J. P.; Lenzi, S. M.; Leoni, S.; Lister, C. J.; Mengoni, D.; Napoli, D. R.; Pechenaya, O. L.; Recchia, F.; Reviol, W.; Sarantites, D. G.; Seweryniak, D.; Ur, C. A.; Zhu, S.

    2012-03-01

    Excited states of the N=Z=33 nucleus 66As have been populated in a fusion-evaporation reaction and studied using γ-ray spectroscopic techniques. Special emphasis was put into the search for candidates for the T=1 states. A new 3+ isomer has been observed with a lifetime of 1.1(3) ns. This is believed to be the predicted oblate shape isomer. The excited levels are discussed in terms of the shell model and of the complex excited Vampir approaches. Coulomb energy differences are determined from the comparison of the T=1 states with their analog partners. The unusual behavior of the Coulomb energy differences in the A=70 mass region is explained through different shape components (oblate and prolate) within the members of the same isospin multiplets. This breaking of the isospin symmetry is attributed to the correlations induced by the Coulomb interaction.

  13. On the Coulomb displacement energy

    International Nuclear Information System (INIS)

    Sato, H.

    1976-01-01

    The Coulomb displacement energies of the T=1/2 mirror nuclei (A=15,17,27,29,31,33,39 and 41) are re-examined with the best available HF wave functions (the DME and the Skyrme II interaction), with the inclusion of all electromagnetic corrections. The results are compared with the experimental s.p. charge dependent energies extracted from the experimental data taking into account admixtures of core-excitation corrections with the help of present shell-model and co-existence model calculations. Although the so-called Nolen-Schiffer anomaly is not removed by these improvements, it is found that the remaining observed anomalies in the ground states of s.p. and s.h. systems can be resolved with the introduction of a simple, phenomenological charge symmetry breaking nucleon-nucleon force. This force can also account for the observed anomalies in the higher excited s.p. states, while those of the deeper s.h. states need further explanation. (Auth.)

  14. Correlated wave functions for three-particle systems with Coulomb interaction - The muonic helium atom

    Science.gov (United States)

    Huang, K.-N.

    1977-01-01

    A computational procedure for calculating correlated wave functions is proposed for three-particle systems interacting through Coulomb forces. Calculations are carried out for the muonic helium atom. Variational wave functions which explicitly contain interparticle coordinates are presented for the ground and excited states. General Hylleraas-type trial functions are used as the basis for the correlated wave functions. Excited-state energies of the muonic helium atom computed from 1- and 35-term wave functions are listed for four states.

  15. Coulomb displacement energies of the T=1, J=0 states of A=42 nuclei

    International Nuclear Information System (INIS)

    Sato, H.

    1978-01-01

    Coulomb displacement energies of the T=1, J=0 + and 6 1 + states of A=42 nuclei are analyzed with previously known charge dependent forces and effects, and with the available Hartree-Fock single-particle wave functions. From the study of the Coulomb displacement energies of the 6 1 + states it is found that the present knowledge on the charge dependence, including a phenomenological charge symmetry breaking force previously introduced so as to help explain the Nolen-Schiffer anomaly, gives a sufficient and consistent explanation for both single-particle and two-particle systems. From the study of the 0 + states, it is found that the Coulomb displacement energies of the second 0 2 + states can be explained with a compensation between the smaller Coulomb energies of the second lowest two-particle state and larger ones of the deformed 4p-2h state. (Auth.)

  16. Excited neutral atomic fragments in the strong-field dissociation of N2 molecules

    International Nuclear Information System (INIS)

    Nubbemeyer, T; Eichmann, U; Sandner, W

    2009-01-01

    Excited neutral N* fragments with energies between 3 eV and 15 eV have been observed from the dissociation of N 2 molecules in strong laser fields. The kinetic energy spectrum of the excited neutral atoms corresponds to Coulomb explosion processes involving N + ions. This supports the assumption that the production of excited neutral fragments stems from a process in which one of the participating ions in the Coulomb explosion captures an electron into a Rydberg state.

  17. The quadrupole moment of the first excited state of 18O

    International Nuclear Information System (INIS)

    Fewel, M.P.; Baxter, A.M.; Kean, D.C.; Spear, R.H.

    1976-11-01

    Using the re-orientation effect in Coulomb excitation, the quadrupole moment, Qsub(2 + ), of the first excited state of 18 O is found to be -0.100 +- 0.030 eb. The analysis assumes, on the basis of previous measurements, that B(E2; 0 + → 2 + ) = 0.0044 +- 0.0004 e 2 b 2 . A correction (+0.032 eb) for the effect of the giant dipole resonance, based on the hydrodynamic model, has been applied. Evidence is presented that some other determinations of Qsub(2 + ) were performed at too high a bombarding energy. The present value of Qsub(2 + ) is smaller in magnitude than that reported by Kleinfeld et al. (1975), but remains larger than the value of -0.034 eb predicted by a recent shell-model calculation. (Author)

  18. Excited states 2

    CERN Document Server

    Lim, Edward C

    2013-01-01

    Excited States, Volume 2 is a collection of papers that deals with molecules in the excited states. The book describes the geometries of molecules in the excited electronic states. One paper describes the geometries of a diatomic molecule and of polyatomic molecules; it also discusses the determination of the many excited state geometries of molecules with two, three, or four atoms by techniques similar to diatomic spectroscopy. Another paper introduces an ordered theory related to excitons in pure and mixed molecular crystals. This paper also presents some experimental data such as those invo

  19. Excited state mass spectra of doubly heavy Ξ baryons

    Energy Technology Data Exchange (ETDEWEB)

    Shah, Zalak; Rai, Ajay Kumar [Sardar Vallabhbhai National Institute of Technology, Department of Applied Physics, Surat, Gujarat (India)

    2017-02-15

    In this paper, the mass spectra are obtained for doubly heavy Ξ baryons, namely, Ξ{sub cc}{sup +}, Ξ{sub cc}{sup ++}, Ξ{sub bb}{sup -}, Ξ{sub bb}{sup 0}, Ξ{sub bc}{sup 0} and Ξ{sub bc}{sup +}. These baryons consist of two heavy quarks (cc, bb, and bc) with a light (d or u) quark. The ground, radial, and orbital states are calculated in the framework of the hypercentral constituent quark model with Coulomb plus linear potential. Our results are also compared with other predictions, thus, the average possible range of excited states masses of these Ξ baryons can be determined. The study of the Regge trajectories is performed in (n, M{sup 2}) and (J, M{sup 2}) planes and their slopes and intercepts are also determined. Lastly, the ground state magnetic moments of these doubly heavy baryons are also calculated. (orig.)

  20. Imaging of Coulomb-Driven Quantum Hall Edge States

    KAUST Repository

    Lai, Keji; Kundhikanjana, Worasom; Kelly, Michael A.; Shen, Zhi-Xun; Shabani, Javad; Shayegan, Mansour

    2011-01-01

    The edges of a two-dimensional electron gas (2DEG) in the quantum Hall effect (QHE) regime are divided into alternating metallic and insulating strips, with their widths determined by the energy gaps of the QHE states and the electrostatic Coulomb

  1. Quasi-stationary states and fermion pair creation from a vacuum in supercritical Coulomb field

    Science.gov (United States)

    Khalilov, V. R.

    2017-12-01

    Creation of charged fermion pair from a vacuum in so-called supercritical Coulomb potential is examined for the case when fermions can move only in the same (one) plane. In which case, quantum dynamics of charged massive or massless fermions can be described by the two-dimensional Dirac Hamiltonians with an usual (-a/r) Coulomb potential. These Hamiltonians are singular and require the additional definition in order for them to be treated as self-adjoint quantum-mechanical operators. We construct the self-adjoint two-dimensional Dirac Hamiltonians with a Coulomb potential and determine the quantum-mechanical states for such Hamiltonians in the corresponding Hilbert spaces of square-integrable functions. We determine the scattering amplitude in which the self-adjoint extension parameter is incorporated and then obtain equations implicitly defining possible discrete energy spectra of the self-adjoint Dirac Hamiltonians with a Coulomb potential. It is shown that this quantum system becomes unstable in the presence of a supercritical Coulomb potential which manifests in the appearance of quasi-stationary states in the lower (negative) energy continuum. The energy spectrum of those states is quasi-discrete, consists of broadened levels with widths related to the inverse lifetimes of the quasi-stationary states as well as the probability of creation of charged fermion pair by a supercritical Coulomb field. Explicit analytical expressions for the creation probabilities of charged (massive or massless) fermion pair are obtained in a supercritical Coulomb field.

  2. Inner shell coulomb ionization by heavy charged particles studied by the SCA model

    International Nuclear Information System (INIS)

    Hansteen, J.M.

    1976-06-01

    An outline is given of the development of and some achievements hitherto gained from the semi-classical approximation (SCA) model of atomic Coulomb excitation by heavy charged particles. A few very recent results (1975-1976) are incorporated in the discussion. The SCA model has by now reached a mature state. Hence it seems reasonable to regard the atomic Coulomb excitation phenomenon as part of the extremely complicated excitation mechanism operative in the general ion-atom collision. A clear understanding of the complicated X-ray producing mechanisms in heavy-ion-atom collisions is lacking at present. Despite these facts, the conceptually simple SCA model has furthered our understanding far beyond initial expectations. Moreover, this model has at the same time provided a well-founded starting point for continued researches in this rapidly expanding field of physics. (JIW)

  3. Interatomic Coulombic electron capture

    International Nuclear Information System (INIS)

    Gokhberg, K.; Cederbaum, L. S.

    2010-01-01

    In a previous publication [K. Gokhberg and L. S. Cederbaum, J. Phys. B 42, 231001 (2009)] we presented the interatomic Coulombic electron capture process--an efficient electron capture mechanism by atoms and ions in the presence of an environment. In the present work we derive and discuss the mechanism in detail. We demonstrate thereby that this mechanism belongs to a family of interatomic electron capture processes driven by electron correlation. In these processes the excess energy released in the capture event is transferred to the environment and used to ionize (or to excite) it. This family includes the processes where the capture is into the lowest or into an excited unoccupied orbital of an atom or ion and proceeds in step with the ionization (or excitation) of the environment, as well as the process where an intermediate autoionizing excited resonance state is formed in the capturing center which subsequently deexcites to a stable state transferring its excess energy to the environment. Detailed derivation of the asymptotic cross sections of these processes is presented. The derived expressions make clear that the environment assisted capture processes can be important for many systems. Illustrative examples are presented for a number of model systems for which the data needed to construct the various capture cross sections are available in the literature.

  4. Coulomb interaction in multiple scattering theory

    International Nuclear Information System (INIS)

    Ray, L.; Hoffmann, G.W.; Thaler, R.M.

    1980-01-01

    The treatment of the Coulomb interaction in the multiple scattering theories of Kerman-McManus-Thaler and Watson is examined in detail. By neglecting virtual Coulomb excitations, the lowest order Coulomb term in the Watson optical potential is shown to be a convolution of the point Coulomb interaction with the distributed nuclear charge, while the equivalent Kerman-McManus-Thaler Coulomb potential is obtained from an averaged, single-particle Coulombic T matrix. The Kerman-McManus-Thaler Coulomb potential is expressed as the Watson Coulomb term plus additional Coulomb-nuclear and Coulomb-Coulomb cross terms, and the omission of the extra terms in usual Kerman-McManus-Thaler applications leads to negative infinite total reaction cross section predictions and incorrect pure Coulomb scattering limits. Approximations are presented which eliminate these anomalies. Using the two-potential formula, the full projectile-nucleus T matrix is separated into two terms, one resulting from the distributed nuclear charge and the other being a Coulomb distorted nuclear T matrix. It is shown that the error resulting from the omission of the Kerman-McManus-Thaler Coulomb terms is effectively removed when the pure Coulomb T matrix in Kerman-McManus-Thaler is replaced by the analogous quantity in the Watson approach. Using the various approximations, theoretical angular distributions are obtained for 800 MeV p+ 208 Pb elastic scattering and compared with experimental data

  5. Shape coexistence measurements in even-even neutron-deficient polonium isotopes by Coulomb excitation, using REX-ISOLDE and the Ge MINIBALL array

    CERN Multimedia

    Butler, P; Bastin, B; Kruecken, R; Voulot, D; Rahkila, P J; Orr, N A; Srebrny, J; Grahn, T; Clement, E; Paul, E S; Gernhaeuser, R A; Dorsival, A; Diriken, J V J; Huyse, M L; Iwanicki, J S

    The neutron-deficient polonium isotopes with two protons outside the closed Z=82 shell represent a set of nuclei with a rich spectrum of nucleus structure phenomena. While the onset of the deformation in the light Po isotopes is well established experimentally, questions remain concerning the sign of deformation and the magnitude of the mixing between different configurations. Furthermore, controversy is present with respect to the transition from the vibrational-like character of the heavier Po isotopes to the shape coexistence mode observed in the lighter Po isotopes. We propose to study this transition in the even-mass neutron-deficient $^{198,200,202}$Po isotopes by using post-accelerated beams from REX-ISOLDE and "safe"-energy Coulomb excitation. $\\gamma$- rays will be detected by the MINIBALL array. The measurements of the Coulomb excitation differential cross section will allow us to deduce both the transition and diagonal matrix elements for these nuclei and, combined with lifetime measurements, the s...

  6. Enhanced coulomb counting method for estimating state-of-charge and state-of-health of lithium-ion batteries

    International Nuclear Information System (INIS)

    Ng, Kong Soon; Moo, Chin-Sien; Chen, Yi-Ping; Hsieh, Yao-Ching

    2009-01-01

    The coulomb counting method is expedient for state-of-charge (SOC) estimation of lithium-ion batteries with high charging and discharging efficiencies. The charging and discharging characteristics are investigated and reveal that the coulomb counting method is convenient and accurate for estimating the SOC of lithium-ion batteries. A smart estimation method based on coulomb counting is proposed to improve the estimation accuracy. The corrections are made by considering the charging and operating efficiencies. Furthermore, the state-of-health (SOH) is evaluated by the maximum releasable capacity. Through the experiments that emulate practical operations, the SOC estimation method is verified to demonstrate the effectiveness and accuracy.

  7. Excited states v.6

    CERN Document Server

    Lim, Edward C

    1982-01-01

    Excited States, Volume 6 is a collection of papers that discusses the excited states of molecules. The first paper discusses the linear polyene electronic structure and potential surfaces, considering both the theoretical and experimental approaches in such electronic states. This paper also reviews the theory of electronic structure and cites some experimental techniques on polyene excitations, polyene spectroscopic phenomenology, and those involving higher states of polyenes and their triplet states. Examples of these experimental studies of excited states involve the high-resolution one-pho

  8. First-principles investigation of quantum transport through an endohedral N@C60 in the Coulomb blockade regime.

    Science.gov (United States)

    Yu, Zhizhou; Chen, Jian; Zhang, Lei; Wang, Jian

    2013-12-11

    We report an investigation of Coulomb blockade transport through an endohedral N@C60 weakly coupled with aluminum leads, employing the first-principles method combined with the Keldysh non-equilibrium Green's function derived from the equation of motion beyond the Hartree-Fock approximation. The differential conductance characteristics of the molecular device are calculated within the Coulomb blockade regime, which shows the Coulomb diamond as observed experimentally. When the gate voltage is less than that of the degeneracy point, there are two peaks in the differential conductance with an excited state induced by the change of the exchange interaction between the spin of C60 and the encapsulated nitrogen atom due to the transition from N@C(1-)(60) to N@C(2-)(60), while for a gate voltage larger than that of the degeneracy point, no excited state is available due to the quenching of exchange energy. As a result, there is only one Coulomb blockade peak in the differential conductance from the electron tunneling through the highest energy level below the Fermi level. Our first-principles results are in good agreement with experimental data obtained by an endohedral N@C60 molecular device.

  9. Measured lifetimes of states in 197Au and a critical comparison with the weak-coupling core-excitation model

    International Nuclear Information System (INIS)

    Bolotin, H.H.; Kennedy, D.L.; Linard, B.J.; Stuchbery, A.E.

    1979-01-01

    The lifetimes of five excited states in 197 Au up to an excitation energy of 885 keV were measured by the recoil-distance method (RDM). These levels were populated by Coulomb excitation using both 90 MeV 20 Ne and 120 MeV 35 Cl ion beams. The experimentally determined spectroscopy of the low-lying levels 3/2 + (ground state) and 1/2 + , (3/2) + 2 , 5/2 + and 7/2 + at 77.3, 268.8, 278.9, and 547.5 keV excitation energy, respectively, has been critically compared with the detailed predictions of the de-Shalit weak-coupling core-excitation model. When the model is taken to represent the case of a dsub(3/2) proton hole coupled to a 198 Hg core, the model parameters obtained are in accord with the criteria implicit for weak core coupling and, at the same time, are in remarkably good agreement with virtually all measured E2 and M1 transition rates. (Auth.)

  10. Excited states

    CERN Document Server

    Lim, Edward C

    1974-01-01

    Excited States, Volume I reviews radiationless transitions, phosphorescence microwave double resonance through optical spectra in molecular solids, dipole moments in excited states, luminescence of polar molecules, and the problem of interstate interaction in aromatic carbonyl compounds. The book discusses the molecular electronic radiationless transitions; the double resonance techniques and the relaxation mechanisms involving the lowest triplet state of aromatic compounds; as well as the optical spectra and relaxation in molecular solids. The text also describes dipole moments and polarizab

  11. Approximative analytic eigenvalues for orbital excitations in the case of a coulomb potential plus linear and quadratic radial terms

    International Nuclear Information System (INIS)

    Rekab, S.; Zenine, N.

    2006-01-01

    We consider the three dimensional non relativistic eigenvalue problem in the case of a Coulomb potential plus linear and quadratic radial terms. In the framework of the Rayleigh-Schrodinger Perturbation Theory, using a specific choice of the unperturbed Hamiltonian, we obtain approximate analytic expressions for the eigenvalues of orbital excitations. The implications and the range of validity of the obtained analytic expression are discussed

  12. Proton-/sup 90/Zr interaction at sub-Coulomb proton energies

    International Nuclear Information System (INIS)

    Laird, C.E.; Flynn, D.; Hershberger, R.L.; Gabbard, F.

    1987-01-01

    The proton-/sup 90/Zr interaction at sub-Coulomb energies has been investigated in the context of the Lane model, with isospin coupling included, and with alternate decay modes represented with the Hauser-Feshbach model. Scattering and reaction cross sections were accurately measured in order to obtain enough information to constrain the real and absorptive parts of the proton potential. Differential elastic scattering excitation functions were measured at back angles of 135 0 and 165 0 from 2 to 7 MeV, with cross section accuracies of 3%. The energy range was sufficient to go from a region where the backscattering was predominantly Coulomb, enabling additional checks on the cross section accuracies, to a region where the gross structure of the cross sections deviated significantly from Rutherford scattering. Radiative capture cross sections were measured from 1.9 to 5.7 MeV proton energies. The capture cross sections were obtained by summing the measured cross sections for the first two primary gamma rays in addition to some 34 other transitions which terminated on the ground and first excited state. The total inelastic scattering cross section to all /sup 90/Zr excited states (except the first excited state which has been previously measured) was measured at several energies between 3.9 and 5.7 MeV by observing the radiative decay of the residual, excited /sup 90/Zr nuclei. The analysis yielded several model parameters suggestive of large nuclear structure effects. The depth of the absorptive potential was found to vary as W/sub D/ = 2.73+0.70 E/sub p/ in the 2 to 7 MeV proton energy range studied. A real diffuseness of 0.54 fm, significantly smaller than that obtained in neighboring nuclei, was obtained

  13. Optically induced structural phase transitions in ion Coulomb crystals

    DEFF Research Database (Denmark)

    Horak, Peter; Dantan, Aurelien Romain; Drewsen, Michael

    2012-01-01

    We investigate numerically the structural dynamics of ion Coulomb crystals confined in a three-dimensional harmonic trap when influenced by an additional one-dimensional optically induced periodical potential. We demonstrate that transitions between thermally excited crystal structures, such as b......We investigate numerically the structural dynamics of ion Coulomb crystals confined in a three-dimensional harmonic trap when influenced by an additional one-dimensional optically induced periodical potential. We demonstrate that transitions between thermally excited crystal structures...

  14. Is the ground state of Yang-Mills theory Coulombic?

    OpenAIRE

    Heinzl, Thomas; Ilderton, Anton; Langfeld, Kurt; Lavelle, Martin; Lutz, Wolfgang; McMullan, David

    2008-01-01

    We study trial states modelling the heavy quark-antiquark ground state in SU(2) Yang-Mills theory. A state describing the flux tube between quarks as a thin string of glue is found to be a poor description of the continuum ground state; the infinitesimal thickness of the string leads to UV artifacts which suppress the overlap with the ground state. Contrastingly, a state which surrounds the quarks with non-abelian Coulomb fields is found to have a good overlap with the ground state for all ch...

  15. Coulombic charge ice

    Science.gov (United States)

    McClarty, P. A.; O'Brien, A.; Pollmann, F.

    2014-05-01

    We consider a classical model of charges ±q on a pyrochlore lattice in the presence of long-range Coulomb interactions. This model first appeared in the early literature on charge order in magnetite [P. W. Anderson, Phys. Rev. 102, 1008 (1956), 10.1103/PhysRev.102.1008]. In the limit where the interactions become short ranged, the model has a ground state with an extensive entropy and dipolar charge-charge correlations. When long-range interactions are introduced, the exact degeneracy is broken. We study the thermodynamics of the model and show the presence of a correlated charge liquid within a temperature window in which the physics is well described as a liquid of screened charged defects. The structure factor in this phase, which has smeared pinch points at the reciprocal lattice points, may be used to detect charge ice experimentally. In addition, the model exhibits fractionally charged excitations ±q/2 which are shown to interact via a 1/r potential. At lower temperatures, the model exhibits a transition to a long-range ordered phase. We are able to treat the Coulombic charge ice model and the dipolar spin ice model on an equal footing by mapping both to a constrained charge model on the diamond lattice. We find that states of the two ice models are related by a staggering field which is reflected in the energetics of these two models. From this perspective, we can understand the origin of the spin ice and charge ice ground states as coming from a dipolar model on a diamond lattice. We study the properties of charge ice in an external electric field, finding that the correlated liquid is robust to the presence of a field in contrast to the case of spin ice in a magnetic field. Finally, we comment on the transport properties of Coulombic charge ice in the correlated liquid phase.

  16. Coulomb-nuclear interference with 6Li: Isospin character of the 21+ excitation in 70,72,74Ge

    International Nuclear Information System (INIS)

    Barbosa, M.D.L.; Borello-Lewin, T.; Horodynski-Matsushigue, L.B.; Duarte, J.L.M.; Rodrigues, C.L.; Rodrigues, M.R.D.; Ukita, G.M.

    2005-01-01

    Ratios of B(E2) to B(IS2), that is, of the reduced quadrupole transition probabilities related, respectively, to charge and mass were extracted through Coulomb-nuclear interference (CNI) for the excitation of the 2 1 + states in 70,72,74 Ge, with a relative accuracy of less than 4%. For this purpose, the CNI angular distributions associated with the inelastic scattering of 28-MeV incident 6 Li ions accelerated by the Sao Paulo Pelletron, and momentum analyzed by the Enge magnetic spectrograph were interpreted within the DWBA-DOMP approach (distorted wave approximation for the scattering process and deformed optical model for the structure representation) with global 6 Li optical parameters. The present CNI results demonstrate an abrupt change in the B(E2)/B(IS2) ratio for 74 Ge: although for 70,72 Ge, values of the order of 1.0 or slightly higher were obtained, this ratio is 0.66 (7) for 74 Ge. The heavier Ge isotope is thus one of the few nuclei that, so far, have been shown to present clear mixed symmetry components in their ground-state band

  17. Magnetic Coulomb phase in the spin ice Ho2Ti2O7.

    Science.gov (United States)

    Fennell, T; Deen, P P; Wildes, A R; Schmalzl, K; Prabhakaran, D; Boothroyd, A T; Aldus, R J; McMorrow, D F; Bramwell, S T

    2009-10-16

    Spin-ice materials are magnetic substances in which the spin directions map onto hydrogen positions in water ice. Their low-temperature magnetic state has been predicted to be a phase that obeys a Gauss' law and supports magnetic monopole excitations: in short, a Coulomb phase. We used polarized neutron scattering to show that the spin-ice material Ho2Ti2O7 exhibits an almost perfect Coulomb phase. Our result proves the existence of such phases in magnetic materials and strongly supports the magnetic monopole theory of spin ice.

  18. Giant resonances on excited states

    International Nuclear Information System (INIS)

    Besold, W.; Reinhard, P.G.; Toepffer, C.

    1984-01-01

    We derive modified RPA equations for small vibrations about excited states. The temperature dependence of collective excitations is examined. The formalism is applied to the ground state and the first excited state of 90 Zr in order to confirm a hypothesis which states that not only the ground state but every excited state of a nucleus has a giant resonance built upon it. (orig.)

  19. Calculation of nuclear excitation in an electron transition

    Energy Technology Data Exchange (ETDEWEB)

    Pisk, K. (Institut Rudjer Boskovic, Zagreb (Yugoslavia)); Kaliman, Z. (Rijeka Univ. (Yugoslavia). Faculty of Pedagogics); Logan, B.A. (Ottawa Univ., ON (Canada). Ottawa-Carleton Centre for Physics)

    1989-11-06

    We have made a theoretical investigation of nuclear excitation during an electron transition (NEET). Our approach allows us to express the NEET probabilities in terms of the excited nuclear level width, the energy difference between the nuclear and electron transition, the Coulomb interaction between the initial electron states, and the electron level width. A comparison is made with the available experimental results. (orig.).

  20. Electronic properties of excited states in single InAs quantum dots

    International Nuclear Information System (INIS)

    Warming, Till

    2009-01-01

    The application of quantum-mechanical effects in semiconductor nanostructures enables the realization of novel opto-electronic devices. Examples are given by single-photon emitters and emitters of entangled photon pairs, both being essential for quantum cryptography, or for qubit systems as needed for quantum computing. InAs/GaAs quantum dots are one of the most promising candidates for such applications. A detailed knowledge of the electronic properties of quantum dots is a prerequisite for this development. The aim of this work is an experimental access to the detailed electronic structure of the excited states in single InAs/GaAs quantum dots including few-particle effects and in particular exchange interaction. The experimental approach is micro photoluminescence excitation spectroscopy (μPLE). One of the main difficulties using μPLE to probe single QDs is the unambiguous assignment of the observed resonances in the spectrum to specific transitions. By comparing micro photoluminescence (μPL) and μPLE spectra, the identification of the main resonances becomes possible. The key is given by the fine structure of the hot trion. Excitation spectroscopy on single charged QDs enables for the first time the complete observation of a non-trivial fine structure of an excitonic complex in a QD, the hot trion. Modelling based on eight-band k.p theory in combination with a configuration interaction scheme is in excellent agreement. Therewith the simulation also enables realistic predictions on the fine structure of the ground-state exciton which is of large importance for single quantum dot devices. Theory concludes from the observed transitions that the structural symmetry of the QDs is broken. Micro photoluminescence excitation spectroscopy combined with resonantly excited micro photoluminescence enables an optical access to the single particle states of the hole without the influence of few-particle coulomb interactions. Based on this knowledge the exciton binding

  1. 11Li Breakup on 208 at energies around the Coulomb barrier.

    Science.gov (United States)

    Fernández-García, J P; Cubero, M; Rodríguez-Gallardo, M; Acosta, L; Alcorta, M; Alvarez, M A G; Borge, M J G; Buchmann, L; Diget, C A; Falou, H A; Fulton, B R; Fynbo, H O U; Galaviz, D; Gómez-Camacho, J; Kanungo, R; Lay, J A; Madurga, M; Martel, I; Moro, A M; Mukha, I; Nilsson, T; Sánchez-Benítez, A M; Shotter, A; Tengblad, O; Walden, P

    2013-04-05

    The inclusive breakup for the (11)Li + (208)Pb reaction at energies around the Coulomb barrier has been measured for the first time. A sizable yield of (9)Li following the (11)Li dissociation has been observed, even at energies well below the Coulomb barrier. Using the first-order semiclassical perturbation theory of Coulomb excitation it is shown that the breakup probability data measured at small angles can be used to extract effective breakup energy as well as the slope of B(E1) distribution close to the threshold. Four-body continuum-discretized coupled-channels calculations, including both nuclear and Coulomb couplings between the target and projectile to all orders, reproduce the measured inclusive breakup cross sections and support the presence of a dipole resonance in the (11)Li continuum at low excitation energy.

  2. Coulomb excitation of $^{116}$Te and $^{118}$Te: a study of collectivity above the Z = 50 shell gap

    CERN Multimedia

    Cederkall, J A; Smith, J F; Voulot, D; Rahkila, P J; Darby, I G; Hadinia, B; Grahn, T; Paul, E S; Wadsworth, R; Bree, N C F; Baeck, T M; Julin, R J; Diriken, J V J; Jenkins, D G; Kroell, T; Leske, J; Huyse, M L

    We propose to study the nature and collectivity of low-energy excitations in $^{116}$Te and $^{118}$Te. We aim to measure the transition probability of the 0$^{+}$ $\\rightarrow$ 2$^{+}$ transition by means of Coulomb excitation, employing REX-ISOLDE and MINIBALL. The proposed study probes the systematics of B(E2) values in light Te nuclei, which lie in a region of the nuclear chart where unusual phenomena and evolution of collectivity have been observed. The proposed study will shed light on the role of the residual proton-neutron interactions in the development of collectivity when approaching the N = Z line. This is a resubmission of the P-277 proposal. The suggestions of INTC have been taken into account and the data from the Yale $^{120}$Te study has been included.

  3. Effect of compound nuclear reaction mechanism in 12C(6Li,d) reaction at sub-Coulomb energy

    Science.gov (United States)

    Mondal, Ashok; Adhikari, S.; Basu, C.

    2017-09-01

    The angular distribution of the 12C(6Li,d) reaction populating the 6.92 and 7.12 MeV states of 16O at sub-Coulomb energy (Ecm=3 MeV) are analysed in the framework of the Distorted Wave Born Approximation (DWBA). Recent results on excitation function measurements and backward angle angular distributions derive ANC for both the states on the basis of an alpha transfer mechanism. In the present work, we show that considering both forward and backward angle data in the analysis, the 7.12 MeV state at sub-Coulomb energy is populated from Compound nuclear process rather than transfer process. The 6.92 MeV state is however produced from direct reaction mechanism.

  4. On Coulomb disintegration of relativistic nuclei and hypernuclei

    International Nuclear Information System (INIS)

    Lyuboshits, V.L.

    1989-01-01

    The dependence of the total cross-section of excitation and disintegration of a relativistic nucleus in the Coulomb field on the energy and parameters characterizing nuclear dimensions is investigated. The analogy with the problem of atomic ionization at the passage of charged particles through matter is used. The results are applied to the description of the Coulomb dissociation of nuclei with small binding energies. An explicit expression for the effective cross-section of the Coulomb disintegration of the hypernucleus-Λ 3 H into a deuteron and Λ-particle. 12 refs

  5. High-energy double photoeffect and photoionization with excitation from 2 {sup 1}S and 2 {sup 3}S states of helium-like ions

    Energy Technology Data Exchange (ETDEWEB)

    Amusia, M.Ya. [The Racah Institute of Physics, Hebrew University, 91904 Jerusalem (Israel); A F Ioffe Physical-Technical Institute, 194921 St Petersburg (Russian Federation); Mikhailov, A.I.; Mikhailov, I.A. [St Petersburg Nuclear Physics Institute, Gatchina, 188350 St Petersburg (Russian Federation)

    1999-10-28

    Double ionization and ionization with excitation of helium-like ions with Z>>1 from 2 {sup 1}S and 2 {sup 3}S states on the absorption of a high-frequency photon have been considered. The analytical calculation is performed in the non-relativistic photon energy range in the lowest order of perturbation theory in the inter-electron interaction. Coulomb wavefunctions and the Coulomb Green function are used as a zeroth-order approximation. Differential and total cross sections of the processes are expressed via the corresponding values for the single photoionization. The photoelectron energy spectrum is obtained in the marginal energy range (i.e. for p{sub 1}>>p{sub 2}, p{sub 1} and p{sub 2} momenta of photoelectrons) for the double-ionization process. Simple relations between the cross sections of double ionization and ionization with excitation are derived. (author)

  6. Excited-state density functional theory

    International Nuclear Information System (INIS)

    Harbola, Manoj K; Hemanadhan, M; Shamim, Md; Samal, P

    2012-01-01

    Starting with a brief introduction to excited-state density functional theory, we present our method of constructing modified local density approximated (MLDA) energy functionals for the excited states. We show that these functionals give accurate results for kinetic energy and exchange energy compared to the ground state LDA functionals. Further, with the inclusion of GGA correction, highly accurate total energies for excited states are obtained. We conclude with a brief discussion on the further direction of research that include the construction of correlation energy functional and exchange potential for excited states.

  7. Critical opalescence and the true dielectric state in a Coulomb system

    Science.gov (United States)

    Bobrov, V. B.; Trigger, S. A.

    2015-04-01

    To study the critical opalescence effect in a two-component Coulomb system consisting of single-type electrons and nuclei, we consider the limit relations for static structure factors and analyze the singularities of the dielectric permittivity. We show that the critical opalescence effect can be observed not only at the critical point corresponding to the gas-liquid phase transition but also near the true dielectric state with zero static conductivity. With the available experimental data taken into account, we assume that the true dielectric state is the limit state of the liquid-liquid phase transition accompanied by sharp variations in the electrical conduction of the substances. We find that if the thermodynamic parameters correspond to the true dielectric state, then the critical opalescence effect can arise in the case where the squared fluctuation in the total number of electrons and nuclei in a two-component Coulomb system becomes infinite, as this occurs at the critical point corresponding to the gas-liquid phase transition.

  8. Rayleigh approximation to ground state of the Bose and Coulomb glasses

    Science.gov (United States)

    Ryan, S. D.; Mityushev, V.; Vinokur, V. M.; Berlyand, L.

    2015-01-01

    Glasses are rigid systems in which competing interactions prevent simultaneous minimization of local energies. This leads to frustration and highly degenerate ground states the nature and properties of which are still far from being thoroughly understood. We report an analytical approach based on the method of functional equations that allows us to construct the Rayleigh approximation to the ground state of a two-dimensional (2D) random Coulomb system with logarithmic interactions. We realize a model for 2D Coulomb glass as a cylindrical type II superconductor containing randomly located columnar defects (CD) which trap superconducting vortices induced by applied magnetic field. Our findings break ground for analytical studies of glassy systems, marking an important step towards understanding their properties. PMID:25592417

  9. Integral equation for Coulomb problem

    International Nuclear Information System (INIS)

    Sasakawa, T.

    1986-01-01

    For short range potentials an inhomogeneous (homogeneous) Lippmann-Schwinger integral equation of the Fredholm type yields the wave function of scattering (bound) state. For the Coulomb potential, this statement is no more valid. It has been felt difficult to express the Coulomb wave function in a form of an integral equation with the Coulomb potential as the perturbation. In the present paper, the author shows that an inhomogeneous integral equation of a Volterra type with the Coulomb potential as the perturbation can be constructed both for the scattering and the bound states. The equation yielding the binding energy is given in an integral form. The present treatment is easily extended to the coupled Coulomb problems

  10. 11Li Breakup on 208Pb at Energies Around the Coulomb Barrier

    DEFF Research Database (Denmark)

    Fernández-García, J.P.; Cubero, M.; Rodríguez-Gallardo, M.

    2013-01-01

    The inclusive breakup for the 11Li+208Pb reaction at energies around the Coulomb barrier has been measured for the first time. A sizable yield of 9Li following the 11Li dissociation has been observed, even at energies well below the Coulomb barrier. Using the first-order semiclassical perturbation...... theory of Coulomb excitation it is shown that the breakup probability data measured at small angles can be used to extract effective breakup energy as well as the slope of B(E1) distribution close to the threshold. Four-body continuum-discretized coupled-channels calculations, including both nuclear...... and Coulomb couplings between the target and projectile to all orders, reproduce the measured inclusive breakup cross sections and support the presence of a dipole resonance in the 11Li continuum at low excitation energy....

  11. Excited state mass spectra of doubly heavy baryons Ω{sub cc}, Ω{sub bb} and Ω{sub bc}

    Energy Technology Data Exchange (ETDEWEB)

    Shah, Zalak; Rai, Ajay Kumar [Sardar Vallabhbhai National Institute of Technology, Department of Applied Physics, Surat, Gujarat (India); Thakkar, Kaushal [GIDC Degree Engineering college, Department of Applied Sciences and Humanities, Abrama, Navsari (India)

    2016-10-15

    We discuss the mass spectrum of Ω baryon with two heavy quarks and one light quark (ccs, bbs, and bcs). The main goal of the paper is to calculate the ground state masses and after that, the positive and negative parity excited states masses are also obtained within a hypercentral constituent quark model, using Coulomb plus linear potential framework. We also added a first order correction to the potential. The mass spectra up to 5S for radial excited states and 1P-5P, 1D-4D, and 1F-2F states for orbital excited states are computed for Ω{sub cc}, Ω{sub bb} and Ω{sub bc} baryons. Our obtained results are compared with other theoretical predictions, which could be a useful complementary tool for the interpretation of experimentally unknown heavy baryon spectra. The Regge trajectory is constructed in both the (n{sub r}, M{sup 2}) and the (J, M{sup 2}) planes for Ω{sub cc}, Ω{sub bb} and Ω{sub bc} baryons and their slopes and intercepts are also determined. Magnetic moments of doubly heavy Ω{sup '}s are also calculated. (orig.) 8.

  12. Coulomb excitation of neutron-rich$^{28,29,30}$Na nuclei with MINIBALL at REX-ISOLDE: Mapping the borders of the island of inversion

    CERN Multimedia

    Butler, P; Cederkall, J A; Reiter, P; Wiens, A; Blazhev, A A; Kruecken, R; Voulot, D; Kalkuehler, M; Wadsworth, R; Gernhaeuser, R A; Hess, H E; Holler, A; Finke, F; Leske, J; Huyse, M L; Seidlitz, M

    We propose to study the properties of neutron-rich nuclei $^{28,29,30}$Na via Coulomb excitation experiments using the REX-ISOLDE facility coupled with the highly efficient MINIBALL array. Reliable B(E2,0$^{+}$ $\\rightarrow$ 2$^{+}$) values for $^{30,32}$Mg were obtained at ISOLDE. Together with recent new results on $^{31}$Mg, collective and single particle properties are probed for Z=12 at the N=20 neutron closed shell, the 'island of inversion'. We would like to extend this knowledge to the neighbouring $^{28,29,30}$Na isotopes where a different transition from the usual filling of the neutron levels into the region with low lying 2p-2h cross shell configurations is predicted by theory. Detailed theoretical predictions on the transition strength in all three Na nuclei are awaiting experimental verification and are the subject of this proposal. At REX beam energies of 3.0 MeV /nucleon the cross-sections for Coulomb excitation are sufficient. Moreover the results from the close-by $^{30,31,32}$Mg nuclei de...

  13. Doubly excited 2s2p 1,3Po resonance states of helium in dense plasmas

    International Nuclear Information System (INIS)

    Kar, Sabyasachi; Ho, Y.K.

    2005-01-01

    We have made an investigation on the 2s2p 1,3 P o resonance states of helium embedded in dense plasma environments. A screened Coulomb potential obtained from the Debye model is used to represent the interaction between the charge particles. A correlated wave function consisting of a generalized exponential expansion has been used to represent the correlation effect. Resonance energies and widths for the doubly excited He embedded in plasmas with various Debye lengths are determined using the stabilization method by calculating the density of resonance states. The resonance energies and widths for various Debye parameters ranging from infinity to a small value for the lowest 1,3 P o resonance states are reported

  14. Doubly excited P-wave resonance states of H− in Debye plasmas

    International Nuclear Information System (INIS)

    Jiao, L. G.; Ho, Y. K.

    2013-01-01

    We investigate the doubly excited P-wave resonance states of H − system in Debye plasmas modeled by static screened Coulomb potentials. The screening effects of the plasma environment on resonance parameters (energy and width) are investigated by employing the complex-scaling method with Hylleraas-type wave functions for both the shape and Feshbach resonances associated with the H(N = 2 to 6) thresholds. Under the screening conditions, the H(N) threshold states are no longer l degenerate, and all the H − resonance energy levels are shifted away from their unscreened values toward the continuum. The influence of Debye plasmas on resonance widths has also been investigated. The shape resonance widths are broadened with increasing plasma screening strength, whereas the Feshbach resonance widths would generally decrease. Our results associated with the H(N = 2) and H(N = 3) thresholds are compared with others in the literature

  15. Lifetimes of excited states in 196198Pt; application of interacting bason approximation model to even Pt isotopes systematics

    International Nuclear Information System (INIS)

    Bolotin, H.H.; Stuchbery, A.E.; Morrison, I.; Kennedy, D.L.; Ryan, C.G.; Sie, S.H.

    1981-01-01

    The lifetimes and lifetime limits of the low-lying excited states up to and including the 6 1 + levels in 196 198 Pt were determined by the rcoil-distance method (RDM). Gamma-ray angular distributions in 198 Pt were also measured. These states were populated by multiple Coulomb excitation using 220-MeV 58 Ni ion beams and the measurements carried out in coincidence with backscattered projectiles. The measured mean lives of the states and B(E2) values inferred for the transitions between levels are presented. These specific findings, and the observed structure systematics obtained from the combination of the present results and those of prior workers for the even 194 - 198 Pt isotopes, are critically compared with our structure calculations employing the Interacting Boson Approximation (IBA) model incorporating a symmetry-breaking quadrupole force. Evaluative comparisons are also made with Boson Expansion Theory (BET) calculations

  16. Preparation of actinide targets by molecular plating for Coulomb excitation studies at ATLAS

    International Nuclear Information System (INIS)

    Greene, J. P.

    1998-01-01

    Molecular plating is now routinely used to prepare sources and targets of actinide elements. Although the technique is simple and fairly reproducible, because of the radioactive nature of the target it is very useful to record various parameters in the preparation of such targets. At Argonne, ∼200 microg/cm 2 thick targets of Pu and Cm were required for Coulomb Excitation (COULEX) Studies with the Argonne-Notre Dame BGO gamma ray facility and later with the GAMMASPHERE. These targets were plated on 50 mg/cm 2 Au backing and were covered with 150 microg/cm 2 Au foil. Targets of 239 Pu, 240 Pu, 242 Pu, 244 Pu and 248 Cm were prepared by dissolving the material in isopropyl alcohol and electroplating the actinide ions by applying 600 volts. The amount of these materials on the target was determined by alpha particle counting and gamma ray counting. Details of the molecular plating and counting will be discussed

  17. Coulomb dissociation of N 20,21

    OpenAIRE

    Röder, Marko; Adachi, Tatsuya; Aksyutina, Yulia; Alcantara, Juan; Altstadt, Sebastian; Alvarez-Pol, Hector; Ashwood, Nicholas; Atar, Leyla; Aumann, Thomas; Avdeichikov, Vladimir; Barr, M.; Beceiro, Saul; Bemmerer, Daniel; Benlliure, Jose; Bertulani, Carlos

    2016-01-01

    Neutron-rich light nuclei and their reactions play an important role in the creation of chemical elements. Here, data from a Coulomb dissociation experiment on N20,21 are reported. Relativistic N20,21 ions impinged on a lead target and the Coulomb dissociation cross section was determined in a kinematically complete experiment. Using the detailed balance theorem, the N19(n,γ)N20 and N20(n,γ)N21 excitation functions and thermonuclear reaction rates have been determined. The N19(n,γ)N20 rate is...

  18. Large degeneracy of excited hadrons and quark models

    International Nuclear Information System (INIS)

    Bicudo, P.

    2007-01-01

    The pattern of a large approximate degeneracy of the excited hadron spectra (larger than the chiral restoration degeneracy) is present in the recent experimental report of Bugg. Here we try to model this degeneracy with state of the art quark models. We review how the Coulomb Gauge chiral invariant and confining Bethe-Salpeter equation simplifies in the case of very excited quark-antiquark mesons, including angular or radial excitations, to a Salpeter equation with an ultrarelativistic kinetic energy with the spin-independent part of the potential. The resulting meson spectrum is solved, and the excited chiral restoration is recovered, for all mesons with J>0. Applying the ultrarelativistic simplification to a linear equal-time potential, linear Regge trajectories are obtained, for both angular and radial excitations. The spectrum is also compared with the semiclassical Bohr-Sommerfeld quantization relation. However, the excited angular and radial spectra do not coincide exactly. We then search, with the classical Bertrand theorem, for central potentials producing always classical closed orbits with the ultrarelativistic kinetic energy. We find that no such potential exists, and this implies that no exact larger degeneracy can be obtained in our equal-time framework, with a single principal quantum number comparable to the nonrelativistic Coulomb or harmonic oscillator potentials. Nevertheless we find it plausible that the large experimental approximate degeneracy will be modeled in the future by quark models beyond the present state of the art

  19. Coulomb energy, vortices, and confinement

    International Nuclear Information System (INIS)

    Greensite, Jeff; Olejnik, Stefan

    2003-01-01

    We estimate the Coulomb energy of static quarks from a Monte Carlo calculation of the correlator of timelike link variables in the Coulomb gauge. We find, in agreement with Cucchieri and Zwanziger, that this energy grows linearly with distance at large quark separations. The corresponding string tension, however, is several times greater than the accepted asymptotic string tension, indicating that a state containing only static sources, with no constituent gluons, is not the lowest energy flux tube state. The Coulomb energy is also measured on thermalized lattices with center vortices removed by the de Forcrand-D'Elia procedure. We find that when vortices are removed, the Coulomb string tension vanishes

  20. Partial radiative recombination cross sections for excited states of hydrogen

    International Nuclear Information System (INIS)

    Fazio, P.M.

    1984-01-01

    In calculating the radiative recombination cross sections for interstellar H II regions, usually only the electric dipole term in the expansion of the interaction Hamiltonian is kept. The dipole and quadrupole transition strengths in closed analytical form are calculated here using the Coulomb wave functions because results for any electron energy and for recombination into any angular momentum state of hydrogen are needed. Several interesting effects are found. First, the transition probabilities are maximum for recombination into specific intermediate angular momentum states at low energies (w < 2eV) and where the free state angular momentum is greater than that of the bound state. Further, that specific intermediate angular momentum state depends on the kinetic energy of the free electron. This behavior is in contrast to the normal behavior of the transition strengths where recombination into s states is greatest and decreases with increasing angular momentum. Second, the quadrupole matrix elements vanish for certain velocities of the free electron. This leads to minima in the corresponding quadrupole cross sections when plotted as a function of the free electron's kinetic energy. Finally, the partial cross sections for highly excited states are greater than previously calculated because of the additional effects of the quadrupole transitions

  1. Atomic excitation and acceleration in strong laser fields

    International Nuclear Information System (INIS)

    Zimmermann, H; Eichmann, U

    2016-01-01

    Atomic excitation in the tunneling regime of a strong-field laser–matter interaction has been recently observed. It is conveniently explained by the concept of frustrated tunneling ionization (FTI), which naturally evolves from the well-established tunneling picture followed by classical dynamics of the electron in the combined laser field and Coulomb field of the ionic core. Important predictions of the FTI model such as the n distribution of Rydberg states after strong-field excitation and the dependence on the laser polarization have been confirmed in experiments. The model also establishes a sound basis to understand strong-field acceleration of neutral atoms in strong laser fields. The experimental observation has become possible recently and initiated a variety of experiments such as atomic acceleration in an intense standing wave and the survival of Rydberg states in strong laser fields. Furthermore, the experimental investigations on strong-field dissociation of molecules, where neutral excited fragments after the Coulomb explosion of simple molecules have been observed, can be explained. In this review, we introduce the subject and give an overview over relevant experiments supplemented by new results. (paper)

  2. Electron impact excitation of xenon from the metastable state to the excited states

    Energy Technology Data Exchange (ETDEWEB)

    Jiang Jun; Dong Chenzhong; Xie Luyou; Zhou Xiaoxin [College of Physics and Electronic Engineering, Northwest Normal University, Lanzhou 730070 (China); Wang Jianguo [Institute of Applied Physics and Computational Mathematic, Beijing 100088 (China)], E-mail: dongcz@nwnu.edu.cn

    2008-12-28

    The electron impact excitation cross sections from the lowest metastable state 5p{sup 5}6sJ = 2 to the six lowest excited states of the 5p{sup 5}6p configuration of xenon are calculated systematically by using the fully relativistic distorted wave method. In order to discuss the effects of target state descriptions on the electron impact excitation cross sections, two correlation models are used to describe the target states based on the multiconfiguration Dirac-Fock (MCDF) method. It is found that the correlation effects play a very important role in low energy impact. For high energy impact, however, the cross sections are not sensitive to the description of the target states, but many more partial waves must be included.

  3. Excitation and photon decay of giant resonances excited by intermediate energy heavy ions

    International Nuclear Information System (INIS)

    Bertrand, F.E.; Beene, J.R.

    1987-01-01

    Inelastic scattering of medium energy heavy ions provides very large cross sections and peak-to-continuum ratios for excitation of giant resonances. For energies above about 50 MeV/nucleon, giant resonances are excited primarily through Coulomb excitation, which is indifferent to isospin, thus providing a good probe for the study of isovector giant resonances. The extremely large cross sections available from heavy ion excitation permit the study of rare decay modes of the giant resonances. In particular, recent measurements have been made of the photon decay of giant resonances following excitation by 22 and 84 MeV/nucleon 17 O projectiles. The singles results at 84 MeV/nucleon yield peak cross sections for the isoscalar giant quadrupole resonance and the isovector giant dipole resonance of approximately 0.8 and 3 barns/sr, respectively. Data on the ground state decay of the isoscalar giant quadrupole and isovector giant dipole resonances are presented and compared with calculations. Decays to low-lying excited states are also discussed. Preliminary results from an experiment to isolate the 208 Pb isovector quadrupole resonance using its gamma decay are presented. 22 refs., 19 figs., 1 tab

  4. In-gap corner states in core-shell polygonal quantum rings.

    Science.gov (United States)

    Sitek, Anna; Ţolea, Mugurel; Niţă, Marian; Serra, Llorenç; Gudmundsson, Vidar; Manolescu, Andrei

    2017-01-10

    We study Coulomb interacting electrons confined in polygonal quantum rings. We focus on the interplay of localization at the polygon corners and Coulomb repulsion. Remarkably, the Coulomb repulsion allows the formation of in-gap states, i.e., corner-localized states of electron pairs or clusters shifted to energies that were forbidden for non-interacting electrons, but below the energies of corner-side-localized states. We specify conditions allowing optical excitation to those states.

  5. In-gap corner states in core-shell polygonal quantum rings

    Science.gov (United States)

    Sitek, Anna; Ţolea, Mugurel; Niţă, Marian; Serra, Llorenç; Gudmundsson, Vidar; Manolescu, Andrei

    2017-01-01

    We study Coulomb interacting electrons confined in polygonal quantum rings. We focus on the interplay of localization at the polygon corners and Coulomb repulsion. Remarkably, the Coulomb repulsion allows the formation of in-gap states, i.e., corner-localized states of electron pairs or clusters shifted to energies that were forbidden for non-interacting electrons, but below the energies of corner-side-localized states. We specify conditions allowing optical excitation to those states.

  6. Effective temperature in relaxation of Coulomb glasses.

    Science.gov (United States)

    Somoza, A M; Ortuño, M; Caravaca, M; Pollak, M

    2008-08-01

    We study relaxation in two-dimensional Coulomb glasses up to macroscopic times. We use a kinetic Monte Carlo algorithm especially designed to escape efficiently from deep valleys around metastable states. We find that, during the relaxation process, the site occupancy follows a Fermi-Dirac distribution with an effective temperature much higher than the real temperature T. Long electron-hole excitations are characterized by T(eff), while short ones are thermalized at T. We argue that the density of states at the Fermi level is proportional to T(eff) and is a good thermometer to measure it. T(eff) decreases extremely slowly, roughly as the inverse of the logarithm of time, and it should affect hopping conductance in many experimental circumstances.

  7. Imaging of Coulomb-Driven Quantum Hall Edge States

    KAUST Repository

    Lai, Keji

    2011-10-01

    The edges of a two-dimensional electron gas (2DEG) in the quantum Hall effect (QHE) regime are divided into alternating metallic and insulating strips, with their widths determined by the energy gaps of the QHE states and the electrostatic Coulomb interaction. Local probing of these submicrometer features, however, is challenging due to the buried 2DEG structures. Using a newly developed microwave impedance microscope, we demonstrate the real-space conductivity mapping of the edge and bulk states. The sizes, positions, and field dependence of the edge strips around the sample perimeter agree quantitatively with the self-consistent electrostatic picture. The evolution of microwave images as a function of magnetic fields provides rich microscopic information around the ν=2 QHE state. © 2011 American Physical Society.

  8. Lifetimes of excited states in 196, 198Pt; Application of interacting boson approximation model to even Pt isotopes systematics

    Science.gov (United States)

    Bolotin, H. H.; Stuchbery, A. E.; Morrison, I.; Kennedy, D. L.; Ryan, C. G.; Sie, S. H.

    1981-11-01

    The lifetimes and lifetime limits of the low-lying excited states up to and including the 6 1+ levels in 196, 198Pt were determined by the recoil-distance method (RDM). Gamma-ray angular distributions in 198Pt were also measured. These states were populated by multiple Coulomb excitation using 220 MeV 58Ni ion beams and the measurements were carried out in coincidence with back-scattered projectiles. The measured mean lives of the states and B(E2) values inferred for the transitions between levels are presented. These specific findings, and the observed structure systematics obtained from the combination of the present results and those of prior workers for the even 194-198Pt isotopes, are critically compared with our structure calculations employing the interacting boson approximation (IBA) model incorporating a symmetry-breaking quadrupole force; evaluative comparisons are also made with boson expansion theory (BET) calculations.

  9. Lifetimes of excited states in 196,198Pt; application of interacting boson approximation model to even Pt isotopes systematics

    International Nuclear Information System (INIS)

    Bolotin, H.H.; Stuchbery, A.E.; Morrison, I.; Kennedy, D.L.; Ryan, C.G.; Sie, S.H.

    1981-01-01

    The lifetimes and lifetime limits of the low-lying excited states up to and including the 6 + 1 levels in sup(196, 198)Pt were determined by the recoil-distance method (RDM). Gamma-ray angular distributions in 198 Pt were also measured. These states were populated by multiple Coulomb excitation using 220 MeV 58 Ni ion beams and the measurements were carried out in coincidence with backscattering projectiles. The measured mean lives of the states and B(E2) values inferred for the transitions between levels are presented. These specific findings, and the observed structure systematics obtained from the combination of the present results and those of prior workers for the even sup(194-198)Pt isotopes, are critically compared with our structure calculations employing the interacting boson approximation (IBA) model incorporating a symmetry-breaking quadrupole force; evaluative comparisons are also made with boson expansion theory (BET) calculations. (orig.)

  10. Coulomb dissociation of 8B at 254 MeV/u

    International Nuclear Information System (INIS)

    Surowka, G.; Iwasa, N.; Boue, F.

    1999-01-01

    As an alternative method to determine the cross section of 7 Be (p, γ) 8 B, the Coulomb dissociation reaction 8 B → 7 Be + p at E inc = 254 MeV/u was measured. Our preliminary results show the dominant role of the dipole excitation in the Coulomb break-up process. The extracted astrophysical S 17 factor is consistent with the lower-value results both of the direct-capture studies, and the RIKEN Coulomb-dissociation experiment at ∼ 50 MeV/u. (author)

  11. Excited-state molecular photoionization dynamics

    International Nuclear Information System (INIS)

    Pratt, S.T.

    1995-01-01

    This review presents a survey of work using resonance-enhanced multiphoton ionization and double-resonance techniques to study excited-state photoionization dynamics in molecules. These techniques routinely provide detail and precision that are difficult to achieve in single-photon ionization from the ground state. The review not only emphasizes new aspects of photoionization revealed in the excited-state experiments but also shows how the excited-state techniques can provide textbook illustrations of some fundamental mechanisms in molecular photoionization dynamics. Most of the examples are confined to diatomic molecules. (author)

  12. Excited states in biological systems

    International Nuclear Information System (INIS)

    Cilento, G.; Zinner, K.; Bechara, E.J.H.; Duran, N.; Baptista, R.C. de; Shimizu, Y.; Augusto, O.; Faljoni-Alario, A.; Vidigal, C.C.C.; Oliveira, O.M.M.F.; Haun, M.

    1979-01-01

    Some aspects of bioluminescence related to bioenergetics are discussed: 1. chemical generation of excited species, by means of two general processes: electron transference and cyclic - and linear peroxide cleavage; 2. biological systems capable of generating excited states and 3. biological functions of these states, specially the non-emissive ones (tripletes). The production and the role of non-emissive excited states in biological systems are analysed, the main purpose of the study being the search for non-emissive states. Experiences carried out in biological systems are described; results and conclusions are given. (M.A.) [pt

  13. Coulomb-Sturmian separable expansion approach: Three-body Faddeev calculations for Coulomb-like interactions

    International Nuclear Information System (INIS)

    Papp, Z.; Plessas, W.

    1996-01-01

    We demonstrate the feasibility and efficiency of the Coulomb-Sturmian separable expansion method for generating accurate solutions of the Faddeev equations. Results obtained with this method are reported for several benchmark cases of bosonic and fermionic three-body systems. Correct bound-state results in agreement with the ones established in the literature are achieved for short-range interactions. We outline the formalism for the treatment of three-body Coulomb systems and present a bound-state calculation for a three-boson system interacting via Coulomb plus short-range forces. The corresponding result is in good agreement with the answer from a recent stochastic-variational-method calculation. copyright 1996 The American Physical Society

  14. Coulomb blockade induced by magnetic field

    International Nuclear Information System (INIS)

    Kusmartsev, F.V.

    1992-01-01

    In this paper, the authors found that a Coulomb blockade can be induced by magnetic field. The authors illustrated this effect on the example of a ring consisting of two and many Josephson junctions. For the ring with two junctions we present an exact solution. The transition into Coulomb blockade state on a ring transforms into a linear array of Josephson junctions, although in latter case the effect of magnetic field disappears. In the state of Coulomb blockade the magnetization may be both diamagnetic and paramagnetic. The Coulomb blockade may also be removed by external magnetic field

  15. Electron-impact excitation of molecular ions

    International Nuclear Information System (INIS)

    Neufeld, D.A.; Dalgarno, A.

    1989-01-01

    A simple expression is derived that relates the rate coefficient for dipole-allowed electron-impact excitation of a molecular ion in the Coulomb-Born approximation to the Einstein A coefficient for the corresponding radiative decay. Results are given for several molecular ions of astrophysical interest. A general analytic expression is obtained for the equilibrium rotational level populations in the ground vibrational state of any molecular ion excited by collisions with electrons. The expression depends only upon the electron temperature, the electron density, and the rotational constant of the molecular ion. A similar expression is obtained for neutral polar molecules

  16. The Coulomb-nuclear force interference in the system 32S + 60Ni

    International Nuclear Information System (INIS)

    Dannhaeuser, G.

    1980-01-01

    For the reaction 60 Ni( 32 S, 32 S*) 60 Ni* using particle-γ-coincidences the excitation functions of 32 S(2 + 1 ) and 60 Ni(2 + 1 ) for projectile energies of 70-100 MeV as well as with Si single counters the angular distribution of the elastically and inelastically scattered 32 S ions for incident energies of 90, 95, and 100 MeV were measured. A comparison of the measurements with the results of different computer codes led to following results: 1.) At the determination of the static quadrupole moment Q 2 of 32 S using the reorientation effect the influence of the nuclear force can be neglected for projectile energies Esub(P) 32 S the value Q 2 = -0.18 +- 0.04 eb was found. (Hereby destructive interference with the virtual excitation of the 2 + 2 -state is assumed). 3.) For projectile energies Esub(P) >= 72 MeV at which the excitation by nuclear forces was small against the Coulomb excitation, an evaluation of the excitation function of 32 S(2 + 1 ) by the semiclassical code NCL, which regards the influence of the nuclear interaction approximatively, yielded values for the static quadrupole moment, which agree within the measurement errors with the above value. 4.) For the quantitative analysis of the measured angular distributions a quantum mechanical CC-code was required. 5.) Using the semiclassical CC-code NCL an illustrative and detailed interpretation of the excitation functions of 32 S(2 + 1 ) and 60 Ni(2 + 1 ) could be given. 6.) The code NCL allows the study of the influence of the Coulomb-nuclear force interference on the temporal behaviour of the excitation process. 7.) Using the code NCL the angular distribution of the decay γ quanta for a fixed particle-scattering angle theta approx. 0 in dependence on the incident energy was calculated. (orig.) [de

  17. Muonic molecules as three-body Coulomb problem in adiabatic approximation

    International Nuclear Information System (INIS)

    Decker, M.

    1994-04-01

    The three-body Coulomb problem is treated within the framework of the hyperspherical adiabatic approach. The surface functions are expanded into Faddeev-type components in order to ensure the equivalent representation of all possible two-body contributions. It is shown that this decomposition reduces the numerical effort considerably. The remaining radial equations are solved both in the extreme and the uncoupled adiabatic approximation to determine the binding energies of the systems (dtμ) and (d 3 Heμ). Whereas the ground state is described very well in the uncoupled adiabatic approximation, the excited states should be treated within the coupled adiabatic approximation to obtain good agreement with variational calculations. (orig.)

  18. Role of the Coulomb interaction in the low-frequency density of states of DNA double helices

    International Nuclear Information System (INIS)

    Garcia, A.E.; Krumhansl, J.A.

    1988-01-01

    The complete vibrational frequency spectrum of several DNA double-helical oligomers is calculated using established pair potentials. Various cutoff values are used for the range of the Coulomb interactions. At very low frequency the integrated density of states shows a noninteger exponent with values ranging from 0.75 to 1.55, depending on the cutoff value for the Coulomb interactions. We conclude that the cumulative densities of states in those molecules depend more on competing interactions than on various proposed universal laws

  19. Coulomb Excitation of Odd-Mass and Odd-Odd Cu Isotopes using REX-ISOLDE and Miniball

    CERN Multimedia

    Lauer, M; Iwanicki, J S

    2002-01-01

    We propose to study the properties of the odd-mass and the odd-odd neutron-rich Cu nuclei applying the Coulomb excitation technique and using the REX-ISOLDE facility coupled to the Miniball array. The results from the Coulex experiments accomplished at REX-ISOLDE after its upgrade to 3 MeV/u during the last year have shown the power of this method and its importance in order to obtain information on the collective properties of even-even nuclei. Performing an experiment on the odd-mass and on the odd-odd neutron-rich Cu isotopes in the vicinity of N=40 should allow us to determine and interpret the effective proton and neutron charges in the region and to unravel the lowest proton-neutron multiplets in $^{68,70}$Cu. This experiment can take the advantage of the unique opportunity to accelerate isomerically separated beams using the RILIS ion source at ISOLDE.

  20. More about orbitally excited hadrons from lattice QCD

    International Nuclear Information System (INIS)

    DeGrand, T.A.; Hecht, M.W.

    1992-01-01

    This is the second of two papers describing the calculation of spectroscopy for orbitally excited states from lattice simulations of quantum chromodynamics. New features include higher statistics for P-wave systems and first results for the spectroscopy of D-wave mesons and baryons, for relatively heavy-quark masses. We parametrize the Coulomb gauge wave functions for P- and D-wave systems and compare them to those of their corresponding S-wave states

  1. Higgs transition from a magnetic Coulomb liquid to a ferromagnet in Yb₂Ti₂O₇.

    Science.gov (United States)

    Chang, Lieh-Jeng; Onoda, Shigeki; Su, Yixi; Kao, Ying-Jer; Tsuei, Ku-Ding; Yasui, Yukio; Kakurai, Kazuhisa; Lees, Martin Richard

    2012-01-01

    In a class of frustrated magnets known as spin ice, magnetic monopoles emerge as classical defects and interact via the magnetic Coulomb law. With quantum-mechanical interactions, these magnetic charges are carried by fractionalized bosonic quasi-particles, spinons, which can undergo Bose-Einstein condensation through a first-order transition via the Higgs mechanism. Here, we report evidence of a Higgs transition from a magnetic Coulomb liquid to a ferromagnet in single-crystal Yb(2)Ti(2)O(7). Polarized neutron scattering experiments show that the diffuse [111]-rod scattering and pinch-point features, which develop on cooling are suddenly suppressed below T(C)~0.21 K, where magnetic Bragg peaks and a full depolarization of the neutron spins are observed with thermal hysteresis, indicating a first-order ferromagnetic transition. Our results are explained on the basis of a quantum spin-ice model, whose high-temperature phase is effectively described as a magnetic Coulomb liquid, whereas the ground state shows a nearly collinear ferromagnetism with gapped spin excitations.

  2. Spurious Excitations in Semiclassical Scattering Theory.

    Science.gov (United States)

    Gross, D. H. E.; And Others

    1980-01-01

    Shows how through proper handling of the nonuniform motion of semiclassical coordinates spurious excitation terms are eliminated. An application to the problem of nuclear Coulomb excitation is presented as an example. (HM)

  3. Molecular resonances in sub-Coulomb energy region (12C-12C, 12C-24Mg, 12C-9Be systems)

    International Nuclear Information System (INIS)

    Takimoto, Kiyohiko; Shimomura, Susumu; Tanaka, Makoto; Murakami, Tetsuya; Fukada, Mamoru; Sakaguchi, Atsushi

    1982-01-01

    Molecular resonance in sub-Coulomb energy region was studied on 12 C- 12 C, 12 C- 24 Mg and 12 C- 9 Be systems. The excitation functions and the angular distributions were measured on the reactions 12 C( 12 C, 8 Besub(g,s,)) 16 Osub(g,s,), 24 Mg( 12 C, α) 32 S and 9 Be ( 12 C, 8 Besub(g,s,)) 13 Csub(g,s,). Sub-Coulomb resonances were observed in all systems and the contribution of the 12 Csub(2nd)*(0 + , 7.65 MeV) state is proposed. (author)

  4. Selfconsistent theory of Coulomb mixing in nuclei

    International Nuclear Information System (INIS)

    Pyatov, N.I.

    1978-01-01

    The theory of isobaric states is considered according to the Coulomb mixing in nuclei. For a given form of the isovestor potential the separable residual interactions are constructed by means of the isotopic invariance principle. The strength parameter of the force is found from a selfconsistency condition. The charge dependent force is represented by the Coulomb effective potential. The theory of the isobaric states is developed using the random phase approximation. The Coulomb mixing effects in the ground and isobaric 0 + states of even-mass nuclei are investigated

  5. Long-range Coulomb interaction effects on the topological phase transitions between semimetals and insulators

    Science.gov (United States)

    Han, SangEun; Moon, Eun-Gook

    2018-06-01

    Topological states may be protected by a lattice symmetry in a class of topological semimetals. In three spatial dimensions, the Berry flux around gapless excitations in momentum space concretely defines a chirality, so a protecting symmetry may be referred to as a chiral symmetry. Prime examples include a Dirac semimetal (DSM) in a distorted spinel, BiZnSiO4, protected by a mirror symmetry, and a DSM in Na3Bi , protected by a rotational symmetry. In these states, topology and chiral symmetry are intrinsically tied. In this Rapid Communication, the characteristic interplay between a chiral symmetry order parameter and an instantaneous long-range Coulomb interaction is investigated with the standard renormalization group method. We show that a topological transition associated with chiral symmetry is stable under the presence of a Coulomb interaction and the electron velocity always becomes faster than the one of a chiral symmetry order parameter. Thus, the transition must not be relativistic, which implies that supersymmetry is intrinsically forbidden by the long-range Coulomb interaction. Asymptotically exact universal ratios of physical quantities such as the energy gap ratio are obtained, and connections with experiments and recent theoretical proposals are also discussed.

  6. Extended Lagrangian Excited State Molecular Dynamics.

    Science.gov (United States)

    Bjorgaard, J A; Sheppard, D; Tretiak, S; Niklasson, A M N

    2018-02-13

    An extended Lagrangian framework for excited state molecular dynamics (XL-ESMD) using time-dependent self-consistent field theory is proposed. The formulation is a generalization of the extended Lagrangian formulations for ground state Born-Oppenheimer molecular dynamics [Phys. Rev. Lett. 2008 100, 123004]. The theory is implemented, demonstrated, and evaluated using a time-dependent semiempirical model, though it should be generally applicable to ab initio theory. The simulations show enhanced energy stability and a significantly reduced computational cost associated with the iterative solutions of both the ground state and the electronically excited states. Relaxed convergence criteria can therefore be used both for the self-consistent ground state optimization and for the iterative subspace diagonalization of the random phase approximation matrix used to calculate the excited state transitions. The XL-ESMD approach is expected to enable numerically efficient excited state molecular dynamics for such methods as time-dependent Hartree-Fock (TD-HF), Configuration Interactions Singles (CIS), and time-dependent density functional theory (TD-DFT).

  7. Photoionization dynamics of excited molecular states

    International Nuclear Information System (INIS)

    Dehmer, J.L.; O'Halloran, M.A.; Tomkins, F.S.; Dehmer, P.M.; Pratt, S.T.

    1987-01-01

    Resonance Enhanced Multiphoton Ionization (REMPI) utilizes tunable dye lasers to ionize an atom or molecule by first preparing an excited state by multiphoton absorption and then ionizing that state before it can decay. This process is highly selective with respect to both the initial and resonant intermediate states of the target, and it can be extremely sensitive. In addition, the products of the REMPI process can be detected as needed by analyzing the resulting electrons, ions, fluorescence, or by additional REMPI. This points to a number of opportunities for exploring excited state physics and chemistry at the quantum-state-specific level. Here we will first give a brief overview of the large variety of experimental approaches to excited state phenomena made possible by REMPI. Then we will examine in more detail, recent studies of the three photon resonant, four photon (3 + 1) ionization of H 2 via the C 'PI/sup u/ state. Strong non-Franck-Condon behavior in the photoelectron spectra of this nominally simple Rydberg state has led to the examination of a variety of dynamical mechanisms. Of these, the role of doubly excited autoionizing states now seems decisive. Progress on photoelectron studies of autoionizing states in H 2 , excited in a (2 + 1) REMPI process via the E, F 1 Σ/sub g/ + will also be briefly discussed. 26 refs., 7 figs

  8. Kinetics studies following state-selective laser excitation

    International Nuclear Information System (INIS)

    Keto, J.W.

    1994-04-01

    The objective of this contract was the study of state-to-state, electronic energy transfer reactions relevant to the excited state chemistry observed in discharges. We studied deactivation reactions and excitation transfer in collisions of excited states of xenon and krypton atoms with Ar, Kr, Xe and chlorine. The reactant states were excited selectively in two-photon transitions using tunable u.v. and v.u.v. lasers. Excited states produced by the collision were observed by their fluorescence. Reaction rates were measured by observing the time dependent decay of signals from reactant and product channels. In addition we measured interaction potentials of the reactants by laser spectroscopy where the laser induced fluorescence or ionization is measured as a function of laser wavelength (excitation spectra) or by measuring fluorescence spectra at fixed laser frequencies with monochromators. The spectra were obtained in the form of either lineshapes or individual lines from rovibrational transitions of bound states. Our research then required several categories of experiments in order to fully understand a reaction process: 1. High resolution laser spectroscopy of bound molecules or lineshapes of colliding pairs is used to determine potential curves for reactants. 2. Direct measurements of state-to-state reaction rates were measured by studying the time dependent loss of excited reactants and the time dependent formation of products. 3. The energy selectivity of a laser can be used to excite reactants on an excited surface with controlled internuclear configurations. For free states of reactants (as exist in a gas cell) this has been termed laser assisted reactions, while for initially bound states (as chemically bound reactants or dimers formed in supersonic beams) the experiments have been termed photo-fragmentation spectroscopy

  9. Preparation of actinide targets by molecular plating for coulomb excitation studies at ATLAS

    CERN Document Server

    Greene, J P; Ahmad, I

    1999-01-01

    Molecular plating is now routinely used to prepare sources and targets of actinide elements. Although the technique is simple and fairly reproducible, because of the radioactive nature of the targets, it is very useful to record various parameters in the preparation process. At Argonne, approx 200 mu g/cm sup 2 thick targets of Pu and Cm were required for Coulomb Excitation (COULEX) studies with the Argonne-Notre Dame boron germanate (BGO) gamma-ray facility and later with the GAMMASPHERE. These targets were plated on 50 mg/cm sup 2 Au backings and were covered with 150 mu g/cm sup 2 Au foil. Targets of sup 2 sup 3 sup 9 Pu, sup 2 sup 4 sup 0 Pu, sup 2 sup 4 sup 2 Pu, sup 2 sup 4 sup 4 Pu and sup 2 sup 4 sup 8 Cm were prepared by dissolving the material in isopropyl alcohol and electroplating the actinide ions by applying 600 V. The amount of these materials on the target was determined by alpha particle counting and gamma-ray counting. Details of the molecular plating and counting will be discussed.

  10. The mechanisms of Excited states in enzymes

    DEFF Research Database (Denmark)

    Petersen, Frederic Nicolas Rønne; Bohr, Henrik

    2010-01-01

    Enzyme catalysis is studied on the basis of excited state processes, which are of electronic, vibrational and thermal nature. The ways of achieving the excited state, such as photo-absorption and ligand binding, are discussed and exemplified by various cases of enzymes.......Enzyme catalysis is studied on the basis of excited state processes, which are of electronic, vibrational and thermal nature. The ways of achieving the excited state, such as photo-absorption and ligand binding, are discussed and exemplified by various cases of enzymes....

  11. Excited state Intramolecular Proton Transfer in Anthralin

    DEFF Research Database (Denmark)

    Møller, Søren; Andersen, Kristine B.; Spanget-Larsen, Jens

    1998-01-01

    Quantum chemical calculations performed on anthralin (1,8-dihydroxy-9(10H)-anthracenone) predict the possibility of an excited-state intramolecular proton transfer process. Fluorescence excitation and emission spectra of the compound dissolved in n-hexane at ambient temperature results in an unus......Quantum chemical calculations performed on anthralin (1,8-dihydroxy-9(10H)-anthracenone) predict the possibility of an excited-state intramolecular proton transfer process. Fluorescence excitation and emission spectra of the compound dissolved in n-hexane at ambient temperature results......, associated with an excited-state intramolecular proton transfer process....

  12. Reorientation-effect measurement of the first 2+ state in 12C: Confirmation of oblate deformation

    Science.gov (United States)

    Kumar Raju, M.; Orce, J. N.; Navrátil, P.; Ball, G. C.; Drake, T. E.; Triambak, S.; Hackman, G.; Pearson, C. J.; Abrahams, K. J.; Akakpo, E. H.; Al Falou, H.; Churchman, R.; Cross, D. S.; Djongolov, M. K.; Erasmus, N.; Finlay, P.; Garnsworthy, A. B.; Garrett, P. E.; Jenkins, D. G.; Kshetri, R.; Leach, K. G.; Masango, S.; Mavela, D. L.; Mehl, C. V.; Mokgolobotho, M. J.; Ngwetsheni, C.; O'Neill, G. G.; Rand, E. T.; Sjue, S. K. L.; Sumithrarachchi, C. S.; Svensson, C. E.; Tardiff, E. R.; Williams, S. J.; Wong, J.

    2018-02-01

    A Coulomb-excitation reorientation-effect measurement using the TIGRESS γ-ray spectrometer at the TRIUMF/ISAC II facility has permitted the determination of the 〈 21+ ‖ E 2 ˆ ‖21+ 〉 diagonal matrix element in 12C from particle-γ coincidence data and state-of-the-art no-core shell model calculations of the nuclear polarizability. The nuclear polarizability for the ground and first-excited (21+) states in 12C have been calculated using chiral NN N4LO500 and NN+3NF350 interactions, which show convergence and agreement with photo-absorption cross-section data. Predictions show a change in the nuclear polarizability with a substantial increase between the ground state and first excited 21+ state at 4.439 MeV. The polarizability of the 21+ state is introduced into the current and previous Coulomb-excitation reorientation-effect analyses of 12C. Spectroscopic quadrupole moments of QS (21+) = + 0.053 (44) eb and QS (21+) = + 0.08 (3) eb are determined, respectively, yielding a weighted average of QS (21+) = + 0.071 (25) eb, in agreement with recent ab initio calculations. The present measurement confirms that the 21+ state of 12C is oblate and emphasizes the important role played by the nuclear polarizability in Coulomb-excitation studies of light nuclei.

  13. Excited-state imaging of cold atoms

    NARCIS (Netherlands)

    Sheludko, D.V.; Bell, S.C.; Vredenbregt, E.J.D.; Scholten, R.E.; Deshmukh, P.C.; Chakraborty, P.; Williams, J.F.

    2007-01-01

    We have investigated state-selective diffraction contrast imaging (DCI) of cold 85Rb atoms in the first excited (52P3/2) state. Excited-state DCI requires knowledge of the complex refractive index of the atom cloud, which was calculated numerically using a semi-classical model. The Autler-Townes

  14. Statistics of excitations in the electron glass model

    Science.gov (United States)

    Palassini, Matteo

    2011-03-01

    We study the statistics of elementary excitations in the classical electron glass model of localized electrons interacting via the unscreened Coulomb interaction in the presence of disorder. We reconsider the long-standing puzzle of the exponential suppression of the single-particle density of states near the Fermi level, by measuring accurately the density of states of charged and electron-hole pair excitations via finite temperature Monte Carlo simulation and zero-temperature relaxation. We also investigate the statistics of large charge rearrangements after a perturbation of the system, which may shed some light on the slow relaxation and glassy phenomena recently observed in a variety of Anderson insulators. In collaboration with Martin Goethe.

  15. Optical studies of multiply excited states

    International Nuclear Information System (INIS)

    Mannervik, S.

    1989-01-01

    Optical studies of multiply-excited states are reviewed with emphasis on emission spectroscopy. From optical measurements, properties such as excitation energies, lifetimes and autoionization widths can be determined with high accuracy, which constitutes a challenge for modern computational methods. This article mainly covers work on two-, three- and four-electron systems, but also sodium-like quartet systems. Furthermore, some comments are given on bound multiply-excited states in negative ions. Fine structure effects on transition wavelengths and lifetimes (autoionization) are discussed. In particular, the most recent experimental and theoretical studies of multiply-excited states are covered. Some remaining problems, which require further attention, are discussed in more detail. (orig.) With 228 refs

  16. Entanglement entropy of excited states

    International Nuclear Information System (INIS)

    Alba, Vincenzo; Fagotti, Maurizio; Calabrese, Pasquale

    2009-01-01

    We study the entanglement entropy of a block of contiguous spins in excited states of spin chains. We consider the XY model in a transverse field and the XXZ Heisenberg spin chain. For the latter, we developed a numerical application of the algebraic Bethe ansatz. We find two main classes of states with logarithmic and extensive behavior in the dimension of the block, characterized by the properties of excitations of the state. This behavior can be related to the locality properties of the Hamiltonian having a given state as the ground state. We also provide several details of the finite size scaling

  17. Characterization of weakly excited final states by shakedown spectroscopy of laser-excited potassium

    International Nuclear Information System (INIS)

    Schulz, J.; Heinaesmaeki, S.; Aksela, S.; Aksela, H.; Sankari, R.; Rander, T.; Lindblad, A.; Bergersen, H.; Oehrwall, G.; Svensson, S.; Kukk, E.

    2006-01-01

    3p shakedown spectra of laser excited potassium atoms as well as direct 3p photoemission of ground state potassium have been studied. These two excitation schemes lead to the same final states and thereby provide a good basis for a detailed study of the 3p 5 (4s3d) 1 configurations of singly ionized potassium and the photoemission processes leading to these configurations. The comparison of direct photoemission from the ground state and conjugate shakedown spectra from 4p 1/2 laser excited potassium made it possible to experimentally determine the character of final states that are only weakly excited in the direct photoemission but have a much higher relative intensity in the shakedown spectrum. Based on considerations of angular momentum and parity conservation the excitation scheme of the final states can be understood

  18. Charge transfer excitations from exact and approximate ensemble Kohn-Sham theory

    Science.gov (United States)

    Gould, Tim; Kronik, Leeor; Pittalis, Stefano

    2018-05-01

    By studying the lowest excitations of an exactly solvable one-dimensional soft-Coulomb molecular model, we show that components of Kohn-Sham ensembles can be used to describe charge transfer processes. Furthermore, we compute the approximate excitation energies obtained by using the exact ensemble densities in the recently formulated ensemble Hartree-exchange theory [T. Gould and S. Pittalis, Phys. Rev. Lett. 119, 243001 (2017)]. Remarkably, our results show that triplet excitations are accurately reproduced across a dissociation curve in all cases tested, even in systems where ground state energies are poor due to strong static correlations. Singlet excitations exhibit larger deviations from exact results but are still reproduced semi-quantitatively.

  19. Coulomb-nuclear interference measurements of 168Yb, 176Hf, 178Hf, and 180Hf and lifetime measurements in 186Hg

    International Nuclear Information System (INIS)

    Nettles, W.G.

    1979-01-01

    Alpha scattering measurements were performed at center-of-mass energies near the Coulomb barrier. These energies allow for nuclear as well as pure Coulomb forces to play a significant role in the excitation process. The interference of these two forces is very sensitive to the sign of the E4 ground-state moment, whereas pure Coulomb excitation is not. Systematics of the E4 moments of the rare earth mass region indicate a transition in the magnitude and sign of the reduced matrix element of the M(E4) operator between 0 + and 4 + states from small and positive to large and negative between Yb and W. Previous Coulomb-nuclear interference measurements show that this reduced matrix element for 180 Hf is large and negative. The present results agree with that conclusion. It is also shown that the above reduced matrix element for 178 Hf, like that of 180 Hf, is large and negative. The small and positive moment (matrix element) for 168 Yb is seen to be consistent with the experimental data. No conclusions are drawn for the E4 moment in 176 Hf. The measurement of nuclear lifetimes shorter than 500 ps requires the use of plastic scintilltor detectors. These detectors, however have very poor energy resolution. A system is described that uses plastic scintillators with a magnetic lens spectrometer for energy selection. The system was used to measure the lifetime of the 522-keV 0 + sate in 186 Hf. A data analysis method using higher-order distribution moments is also presented

  20. Form coexistence in light krypton nuclei. Isomeric spectroscopy of 72,74Kr nuclei and Coulomb excitation of the 76Kr radioactive beam

    International Nuclear Information System (INIS)

    Bouchez, Emmanuelle

    2003-01-01

    The first part of this research thesis proposes an overview of the different theoretical calculations elaborated in the region of light krypton nuclei, and of published experimental results. The second part reports the electron and gamma isomeric spectroscopy of 72,74 Kr nuclei after fragmentation of the projectile by a magnetic separator (experimental installation, experimental results, discussion). The third part reports the study of the Coulomb excitation of the 76 Kr radioactive beam (method and experimental installation, data analysis and results in terms of germanium and silicon spectra, and form of the 76 Kr)

  1. Excited states configurations of the quantum Toda lattice

    International Nuclear Information System (INIS)

    Matsuyama, A.

    2001-01-01

    Excited states configurations of the quantum Toda lattice are studied by the direct diagonalization of the Hamiltonian. The most probable configurations of one-hole and one-particle excitations are shown to be similar to the profiles of classical phonon and soliton excitations, respectively. One-hole excitation states, which are always ground states of definite E m -symmetry of the dihedral group D N , change those structures abruptly with the potential range varied. One-particle excitations, which are buried in complicated excitation spectra, have well-defined configurations similar to the conoidal profile of the classical periodic Toda lattice. The relationship that the hole (particle) excitations in quantum mechanics correspond to the phonon (soliton) excitations in classical mechanics, which has been suggested based on the similarity of dispersion relations, is confirmed in a geometrically understandable way. Based on the study of one-soliton and two-soliton states, the structure of multi-soliton states in quantum mechanics can be conjectured

  2. Coulomb breakup of 31Ne using finite range DWBA

    International Nuclear Information System (INIS)

    Shubhchintak; Chatterjee, R.

    2013-01-01

    Coulomb breakup of nuclei away from the valley of stability have been one of the most successful probes to unravel their structure. However, it is only recently that one is venturing into medium mass nuclei like 23 O and 31 Ne. This is a very new and exciting development which has expanded the field of light exotic nuclei to the deformed medium mass region. In this contribution, an extension of the previously proposed theory of Coulomb breakup within the post-form finite range distorted wave Born approximation to include deformation of the projectile is reported

  3. SU(1,1) coherent states for Dirac–Kepler–Coulomb problem in D+1 dimensions with scalar and vector potentials

    Energy Technology Data Exchange (ETDEWEB)

    Ojeda-Guillén, D., E-mail: dogphysics@gmail.com [Escuela Superior de Física y Matemáticas, Instituto Politécnico Nacional, Ed. 9, Unidad Profesional Adolfo López Mateos, C.P. 07738, México D.F. (Mexico); Mota, R.D. [Escuela Superior de Ingeniería Mecánica y Eléctrica, Unidad Culhuacán, Instituto Politécnico Nacional, Av. Santa Ana No. 1000, Col. San Francisco Culhuacán, Delegación Coyoacán, C.P. 04430, México D.F. (Mexico); Granados, V.D. [Escuela Superior de Física y Matemáticas, Instituto Politécnico Nacional, Ed. 9, Unidad Profesional Adolfo López Mateos, C.P. 07738, México D.F. (Mexico)

    2014-08-14

    We decouple the Dirac's radial equations in D+1 dimensions with Coulomb-type scalar and vector potentials through appropriate transformations. We study each of these uncoupled second-order equations in an algebraic way by using an su(1,1) algebra realization. Based on the theory of irreducible representations, we find the energy spectrum and the radial eigenfunctions. We construct the Perelomov coherent states for the Sturmian basis, which is the basis for the unitary irreducible representation of the su(1,1) Lie algebra. The physical radial coherent states for our problem are obtained by applying the inverse original transformations to the Sturmian coherent states. - Highlights: • We solve the most general Dirac–Kepler–Coulomb problem. • The eigenfunctions and energy spectrum are obtained in a purely algebraic way. • We construct the radial SU(1,1) coherent states for the Kepler–Coulomb problem.

  4. SU(1,1) coherent states for Dirac–Kepler–Coulomb problem in D+1 dimensions with scalar and vector potentials

    International Nuclear Information System (INIS)

    Ojeda-Guillén, D.; Mota, R.D.; Granados, V.D.

    2014-01-01

    We decouple the Dirac's radial equations in D+1 dimensions with Coulomb-type scalar and vector potentials through appropriate transformations. We study each of these uncoupled second-order equations in an algebraic way by using an su(1,1) algebra realization. Based on the theory of irreducible representations, we find the energy spectrum and the radial eigenfunctions. We construct the Perelomov coherent states for the Sturmian basis, which is the basis for the unitary irreducible representation of the su(1,1) Lie algebra. The physical radial coherent states for our problem are obtained by applying the inverse original transformations to the Sturmian coherent states. - Highlights: • We solve the most general Dirac–Kepler–Coulomb problem. • The eigenfunctions and energy spectrum are obtained in a purely algebraic way. • We construct the radial SU(1,1) coherent states for the Kepler–Coulomb problem

  5. Excited states rotational effects on the behavior of excited molecules

    CERN Document Server

    Lim, Edward C

    2013-01-01

    Excited States, Volume 7 is a collection of papers that discusses the excited states of molecules. The first paper reviews the rotational involvement in intra-molecular in vibrational redistribution. This paper analyzes the vibrational Hamiltonian as to its efficacy in detecting the manifestations of intra-molecular state-mixing in time-resolved and time-averaged spectroscopic measurements. The next paper examines the temporal behavior of intra-molecular vibration-rotation energy transfer (IVRET) and the effects of IVRET on collision, reaction, and the decomposition processes. This paper also

  6. Reorientation-effect measurement of the first 2+ state in 12C: Confirmation of oblate deformation

    Directory of Open Access Journals (Sweden)

    M. Kumar Raju

    2018-02-01

    Full Text Available A Coulomb-excitation reorientation-effect measurement using the TIGRESS γ−ray spectrometer at the TRIUMF/ISAC II facility has permitted the determination of the 〈21+‖E2ˆ‖21+〉 diagonal matrix element in 12C from particle−γ coincidence data and state-of-the-art no-core shell model calculations of the nuclear polarizability. The nuclear polarizability for the ground and first-excited (21+ states in 12C have been calculated using chiral NN N4LO500 and NN+3NF350 interactions, which show convergence and agreement with photo-absorption cross-section data. Predictions show a change in the nuclear polarizability with a substantial increase between the ground state and first excited 21+ state at 4.439 MeV. The polarizability of the 21+ state is introduced into the current and previous Coulomb-excitation reorientation-effect analyses of 12C. Spectroscopic quadrupole moments of QS(21+=+0.053(44 eb and QS(21+=+0.08(3 eb are determined, respectively, yielding a weighted average of QS(21+=+0.071(25 eb, in agreement with recent ab initio calculations. The present measurement confirms that the 21+ state of 12C is oblate and emphasizes the important role played by the nuclear polarizability in Coulomb-excitation studies of light nuclei.

  7. Three-body Coulomb bound states

    Science.gov (United States)

    Bhatia, A. K.; Drachman, Richard J.

    1987-01-01

    The binding energies of three-particle systems containing two electrons and one positive particle of mass M are reexamined in an attempt to understand the approximate proportionality of the 1Se ground-state binding energies of the reduced masses, as pointed out by Botero and Green (1986). The contribution to the energy of the mass-polarization term is evaluated. No fundamental principle is involved, since the mass polarization merely decreases somewhat as the mass of the positive particle is reduced below the proton mass. In the case of the excited 3Pe state, this reduction is not sufficient to allow binding when M approaches the electron mass. Some properties of the recently observed negative muonium ion (e/-/ mu/+/ e/-/) are also computed.

  8. Charge independence and charge symmetry breaking interactions and the Coulomb energy anomaly in isobaric analog states

    International Nuclear Information System (INIS)

    Suzuki, Toshio; Sagawa, H.; Giai, N. van.

    1992-01-01

    Effects of CIB (charge independence breaking) and CSB (charge symmetry breaking) interactions on the Coulomb displacement energies of isobaric analog states are investigated for 48 Ca, 90 Zr and 208 Pb. Mass number dependence of the Coulomb energy anomalies is well explained when CIB and CSB interactions are used which reproduce the differences of the scattering lengths as well as those of the effective ranges of low energy nucleon-nucleon scattering. (author) 17 refs., 3 figs., 3 tabs

  9. On calculations of the ground state energy in quantum mechanics

    International Nuclear Information System (INIS)

    Efimov, G.V.

    1991-02-01

    In nonrelativistic quantum mechanics the Wick-ordering method called the oscillator representation suggested to calculate the ground-state energy for a wide class of potentials allowing the existence of a bound state. The following examples are considered: the orbital excitations of the ground-state in the Coulomb plus linear potential, the Schroedinger equation with a ''relativistic'' kinetic energy √p 2 +m 2 , the Coulomb three-body problem. (author). 22 refs, 2 tabs

  10. A note on calm excited states of inflation

    International Nuclear Information System (INIS)

    Ashoorioon, Amjad; Shiu, Gary

    2011-01-01

    We identify a two-parameter family of excited states within slow-roll inflation for which either the corrections to the two-point function or the characteristic signatures of excited states in the three-point function — i.e. the enhancement for the flattened momenta configurations– are absent. These excited states may nonetheless violate the adiabaticity condition maximally. We dub these initial states of inflation calm excited states. We show that these two sets do not intersect, i.e., those that leave the power-spectrum invariant can be distinguished from their bispectra, and vice versa. The same set of calm excited states that leave the two-point function invariant for slow-roll inflation, do the same task for DBI inflation. However, at the level of three-point function, the calm excited states whose flattened configuration signature is absent for slow-roll inflation, will lead to an enhancement for DBI inflation generally, although the signature is smaller than what suggested by earlier analysis. This example also illustrates that imposing the Wronskian condition is important for obtaining a correct estimate of the non-Gaussian signatures

  11. Comment on "Calculations for the one-dimensional soft Coulomb problem and the hard Coulomb limit".

    Science.gov (United States)

    Carrillo-Bernal, M A; Núñez-Yépez, H N; Salas-Brito, A L; Solis, Didier A

    2015-02-01

    In the referred paper, the authors use a numerical method for solving ordinary differential equations and a softened Coulomb potential -1/√[x(2)+β(2)] to study the one-dimensional Coulomb problem by approaching the parameter β to zero. We note that even though their numerical findings in the soft potential scenario are correct, their conclusions do not extend to the one-dimensional Coulomb problem (β=0). Their claims regarding the possible existence of an even ground state with energy -∞ with a Dirac-δ eigenfunction and of well-defined parity eigenfunctions in the one-dimensional hydrogen atom are questioned.

  12. Coulomb thermal properties and stability of the Io plasma torus

    Science.gov (United States)

    Barbosa, D. D.; Coroniti, F. V.; Eviatar, A.

    1983-01-01

    Coulomb collisional energy exchange rates are computed for a model of the Io plasma torus consisting of newly created pickup ions, a background of thermally degraded intermediary ions, and a population of cooler electrons. The electrons are collisionally heated by both the pickup ions and background ions and are cooled by electron impact excitation of plasma ions which radiate in the EUV. It is found that a relative concentration of S III pickup ions forbidden S III/electrons = 0.1 with a temperature of 340 eV can deliver energy to the electrons at a rate of 3 x 10 to the -13th erg/cu cm per sec, sufficient to power the EUV emissions in the Io torus. The model predicts a background ion temperature Ti of about 53 eV and an electron temperature Te of about 5.5 eV on the basis of steady-state energy balance relations at Coulomb rates. The model also predicts electron temperature fluctuations at the 30 percent level on a time scale of less than 11 hours, consistent with recent observations of this phenomenon.

  13. Signatures of Coulomb fission: a theoretical study

    International Nuclear Information System (INIS)

    Oberacker, V.; Kruse, H.; Pinkston, W.T.; Greiner, W.

    1979-01-01

    Evidence for Coulomb fission (CF) is noted first. Then the Hamiltonian is set down and explained, and an expression for the CF probability of CF is obtained. Results are summarized. Figures show the CF probability of 238 U as a function of projectile charge number and the excitation functions for CF of 238 U by 184 W and 136 Xe. 3 figures

  14. Measurement of the Spectroscopic Quadrupole Moment for the 2+1 State in 10Be:. Testing AB Initio Calculations

    Science.gov (United States)

    Orce, J. N.; Djongolov, M.; Navratil, P.; Ball, G.; Garnsworthy, A. B.; Hackman, G.; Lassen, J.; Meissner, J.; Pearson, C. J.; Li, R.; Milovanovic, L.; Sjue, S. K. L.; Teigelhoefer, A.; Triambak, S.; Williams, S. J.; Falou, H. Al; Drake, T. E.; Andreoiu, C.; Cross, D.; Kshetri, R.; Finlay, P.; Garrett, P. E.; Leach, K. G.; Rand, E. T.; Sumithrarachchi, C. S.; Svensson, C. E.; Tardiff, E. R.; Wong, J.; Forssen, C.; Hayes, A. B.; Sarazin, F.; Stoyer, M. A.; Wu, C. Y.

    2013-03-01

    The highly efficient and segmented TIGRESS HPGe γ-ray array at TRIUMF has been used to perform a reorientation effect Coulomb excitation study of the 2+1 state at 3.368 MeV in 10Be. This is the first Coulomb excitation measurement that provides information on diagonal matrix elements for such a high lying first excited state from μ-ray data. With the availability of accurate lifetime data, a restriction on the diagonal matrix element is determined. This result is compared to a no core shell model calculation with the CD-Bonn 2000 two nucleon potential.

  15. Lifetimes of low-lying excited states in 50 36 86Kr

    Science.gov (United States)

    Henderson, J.; Chester, A.; Ball, G. C.; Caballero-Folch, R.; Domingo, T.; Drake, T. E.; Evitts, L. J.; Garnsworthy, A. B.; Hackman, G.; Hallam, S.; Moukaddam, M.; Ruotsalainen, P.; Smallcombe, J.; Smith, J. K.; Starosta, K.; Svensson, C. E.; Williams, J.

    2018-04-01

    Background: The evolution of nuclear magic numbers at extremes of isospin is a topic at the forefront of contemporary nuclear physics. N =50 is a prime example, with increasing experimental data coming to light on potentially doubly magic 100Sn and 78Ni at the proton-rich and proton-deficient extremes, respectively; however, experimental discrepancies exist in the data for less exotic systems. Purpose: In 86Kr the B (E 2 ;21+→01+) value—a key indicator of shell evolution—has been experimentally determined by two different methodologies, with the results deviating by 3 σ . Here, we report on a new high-precision measurement of this value, as well as the first measured lifetimes and hence transition strengths for the 22+ and 3(2) - states in the nucleus. Methods: The Doppler-shift attenuation method was implemented using the TRIUMF-ISAC γ -ray escape-suppressed spectrometer (TIGRESS) γ -ray spectrometer and the TIGRESS integrated plunger device. High-statistics Monte Carlo simulations were utilized to extract lifetimes in accordance with state-of-the-art methodologies. Results: Lifetimes of τ (21+)=336 ±4 (stat.)±20 (sys.) fs, τ (22+)=263 ±9 (stat.)±19 (sys.) fs, and τ (3(2) -)=73 ±6 (stat.)±32 (sys.) fs were extracted. This yields a transition strength for the first-excited state of B (E 2 ;21+→01+)=259 ±3 (stat.)±16 (sys.) e2 fm4. Conclusions: The measured lifetime disagrees with the previous Doppler-shift attenuation method measurement by more than 3 σ , while agreeing well with a previous value extracted from Coulomb excitation. The newly extracted B (E 2 ;21+→01+) value indicates a more significant reduction in the N =50 isotones approaching Z =40 .

  16. Probing intruder configurations in $^{186, 188}$Pb using Coulomb excitation

    CERN Multimedia

    Columb excitation measurements to study the shape coexistence, mixing and quadrupole collectivity of the low-lying levels in neutron-deficient $^{188}$Pb nuclei are proposed with a view to extending similar studies to the $^{186}$Pb midshell nucleus. The HIE-ISOLDE beam of $^{186,188}$Pb nuclei will be delivered to MINIBALL+SPEDE set-up for simultaneous in-beam $\\gamma$-ray and conversion electron spectroscopy. The proposed experiment will allow the sign of the quadrupole deformation parameter to be extracted for the two lowest 2$^{+}$ states in $^{188}$Pb. Moreover, the advent of SPEDE will allow probing of the bandhead 0$^{+}$ states via direct measurements of E0 transitions. Beam development is requested to provide pure and instense $^{186}$Pb beam.

  17. Complex-scaling of screened Coulomb potentials for resonance calculations utilizing the modified Bessel functions

    Science.gov (United States)

    Jiao, Li-Guang; Ho, Yew Kam

    2014-05-01

    The screened Coulomb potential (SCP) has been extensively used in atomic physics, nuclear physics, quantum chemistry and plasma physics. However, an accurate calculation for atomic resonances under SCP is still a challenging task for various methods. Within the complex-scaling computational scheme, we have developed a method utilizing the modified Bessel functions to calculate doubly-excited resonances in two-electron atomic systems with configuration interaction-type basis. To test the validity of our method, we have calculated S- and P-wave resonance states of the helium atom with various screening strengths, and have found good agreement with earlier calculations using different methods. Our present method can be applied to calculate high-lying resonances associated with high excitation thresholds of the He+ ion, and with high-angular-momentum states. The derivation and calculation details of our present investigation together with new results of high-angular-momentum states will be presented at the meeting. Supported by NSC of Taiwan.

  18. Process to produce excited states of atomic nuclei

    International Nuclear Information System (INIS)

    Morita, M.; Morita, R.

    The claims of a patented process which relates to the production of excited states of atomic nuclei are outlined. Among these are (1) production of nuclear excited states by bombarding the atoms with x rays or electrons under given conditions, (2) production of radioactive substances by nuclear excitation with x rays or electrons, (3) separation of specific isotopes from a mixture of isotopes of the same element by means of nuclear excitation followed by chemical treatment. The invention allows production of excited states of atomic nuclei in a relatively simple manner without the need of large apparatus and equipment

  19. Coulomb fission and transfer fission at heavy ion collisions

    International Nuclear Information System (INIS)

    Himmele, G.

    1981-01-01

    In the present thesis the first direct evidence of nuclear fission after inelastic scattering of heavy ions (sup(183,184)W, 152 Sm → 238 U; 184 W → 232 Th; 184 W, 232 Th → 248 Cm) is reported. Experiments which were performed at the UNILAC of the Gesellschaft fuer Schwerionenforschung in Darmstadt show the observed heavy ion induced fission possesses significant properties of the Coulomb fission. The observed dependence of the fission probability for inelastic scattering on the projectile charge proves that the nuclear fission is mediated by the electromagnetic interaction between heavy ions. This result suggests moreover a multiple Coulomb-excitation preceding the fission. Model calculations give a first indication, that the Coulomb fission proceeds mainly from the higher β phonons. In the irradiation with 184 W the fission probability of 232 Th is for all incident energies about 40% smaller that at 238 U. The target dependence of the Coulomb fission however doesn't allow, to give quantitative statements about the position and B(E2)-values of higher lying β phonons. (orig./HSI) [de

  20. Coulomb gap triptych in a periodic array of metal nanocrystals.

    Science.gov (United States)

    Chen, Tianran; Skinner, Brian; Shklovskii, B I

    2012-09-21

    The Coulomb gap in the single-particle density of states (DOS) is a universal consequence of electron-electron interaction in disordered systems with localized electron states. Here we show that in arrays of monodisperse metallic nanocrystals, there is not one but three identical adjacent Coulomb gaps, which together form a structure that we call a "Coulomb gap triptych." We calculate the DOS and the conductivity in two- and three-dimensional arrays using a computer simulation. Unlike in the conventional Coulomb glass models, in nanocrystal arrays the DOS has a fixed width in the limit of large disorder. The Coulomb gap triptych can be studied via tunneling experiments.

  1. Photoionization of excited molecular states using multiphoton excitation techniques

    International Nuclear Information System (INIS)

    Dehmer, P.M.; Pratt, S.T.; Dehmer, J.L.

    1984-01-01

    Photoelectron spectra are reported for three photon resonant, four photon ionization of H 2 via the B 1 Σ + /sub u/, v = 7 (J = 2,4) and C 1 Pi/sub u/, v = 0-4 (J = 1) levels and of N 2 via the o 3 1 Pi/sub u/, v = 1,2, b 1 Pi/sub u/, v = 3-5, and c 1 Pi/sub u/, v = 0 levels. The results reflect both the spectroscopy and the dynamics of photoionization of excited molecular states and are discussed in terms of the selection rules for photoionization and the relative probabilities of photoionization from Rydberg and valence states. In some cases, in accordance with the Franck-Condon principle, the results demonstrate that resonant multiphoton ionization through Rydberg states may be a powerful technique for the production of electronic, vibrational, and rotational state selected ions. However, in other cases, systematic departures from Franck-Condon factors are observed, which reflect the more subtle dynamics of excited state photoionization

  2. Ultrafast excited state relaxation in long-chain polyenes

    International Nuclear Information System (INIS)

    Antognazza, Maria Rosa; Lueer, Larry; Polli, Dario; Christensen, Ronald L.; Schrock, Richard R.; Lanzani, Guglielmo; Cerullo, Giulio

    2010-01-01

    Graphical abstract: Excited state dynamics of a long-chain polyene studied by femtosecond pump-probe spectroscopy. - Abstract: We present a comprehensive study, by femtosecond pump-probe spectroscopy, of excited state dynamics in a polyene that approaches the infinite chain limit. By excitation with sub-10-fs pulses resonant with the 0-0 S 0 → S 2 transition, we observe rapid loss of stimulated emission from the bright excited state S 2 , followed by population of the hot S 1 state within 150 fs. Vibrational cooling of S 1 takes place within 500 fs and is followed by decay back to S 0 with 1 ps time constant. By excitation with excess vibrational energy we also observe the ultrafast formation of a long-living absorption, that is assigned to the triplet state generated by singlet fission.

  3. Coulomb effects in relativistic laser-assisted Mott scattering

    International Nuclear Information System (INIS)

    Ngoko Djiokap, J.M.; Kwato Njock, M.G.; Tetchou Nganso, H.M.

    2004-09-01

    We reconsider the influence of the Coulomb interaction on the process of relativistic Mott scattering in a powerful electromagnetic plane wave for which the ponderomotive energy is of the order of the magnitude of the electron's rest mass. Coulomb effects of the bare nucleus on the laser-dressed electron are treated more completely than in the previous work of Li et al. [J. Phys. B: At. Mol. Opt. Phys. 37 (2004) 653]. To this end we use Coulomb-Dirac-Volkov functions to describe the initial and the final states of the electron. First-order Born differential cross sections of induced and inverse bremsstrahlung are obtained for circularly and linearly polarized laser light. Numerical calculations are carried out from both polarizations, for various nucleus charge values, three angular configurations and an incident energy in the MeV range. It is found that for parameters used in the present work, incorporating Coulomb effects of the target nucleus either in the initial state or in the final state yields cross sections which are quite similar whatever the scattering geometry and polarization considered. When Coulomb distortions are included in both states, the cross sections are strongly modified with the increase of Z, as compared to the outcome of the prior form of the T-matrix treatment. (author)

  4. Excited state kinetics of anthracene-bridge-aniline intramolecular exciplexes

    DEFF Research Database (Denmark)

    Thyrhaug, Erling; Hammershøj, Peter; Kjær, Kasper Skov

    2014-01-01

    excited anthracene state (LE) and an excited state complex (exciplex, EP) in non-polar solvents. The kinetics of the excited state processes were established in decalin from the time-resolved emission, and was shown to be strongly influenced by an electron-transfer state (ET). For quantitative studies...

  5. Charge transfer excitations from excited state Hartree-Fock subsequent minimization scheme

    International Nuclear Information System (INIS)

    Theophilou, Iris; Tassi, M.; Thanos, S.

    2014-01-01

    Photoinduced charge-transfer processes play a key role for novel photovoltaic phenomena and devices. Thus, the development of ab initio methods that allow for an accurate and computationally inexpensive treatment of charge-transfer excitations is a topic that nowadays attracts a lot of scientific attention. In this paper we extend an approach recently introduced for the description of single and double excitations [M. Tassi, I. Theophilou, and S. Thanos, Int. J. Quantum Chem. 113, 690 (2013); M. Tassi, I. Theophilou, and S. Thanos, J. Chem. Phys. 138, 124107 (2013)] to allow for the description of intermolecular charge-transfer excitations. We describe an excitation where an electron is transferred from a donor system to an acceptor one, keeping the excited state orthogonal to the ground state and avoiding variational collapse. These conditions are achieved by decomposing the space spanned by the Hartree-Fock (HF) ground state orbitals into four subspaces: The subspace spanned by the occupied orbitals that are localized in the region of the donor molecule, the corresponding for the acceptor ones and two more subspaces containing the virtual orbitals that are localized in the neighborhood of the donor and the acceptor, respectively. Next, we create a Slater determinant with a hole in the subspace of occupied orbitals of the donor and a particle in the virtual subspace of the acceptor. Subsequently we optimize both the hole and the particle by minimizing the HF energy functional in the corresponding subspaces. Finally, we test our approach by calculating the lowest charge-transfer excitation energies for a set of tetracyanoethylene-hydrocarbon complexes that have been used earlier as a test set for such kind of excitations

  6. Excited State Spectra and Dynamics of Phenyl-Substituted Butadienes

    DEFF Research Database (Denmark)

    Wallace-Williams, Stacie E.; Schwartz, Benjamin J.; Møller, Søren

    1994-01-01

    indicate that phenyl torsional motion is not important to the excited-state dynamics and reveal alternative excited-state reaction pathways. The results demonstrate how molecular systems that are structually similar can exhibit different electronic properties and excited-state dynamics....

  7. Multimode optical fibers: steady state mode exciter.

    Science.gov (United States)

    Ikeda, M; Sugimura, A; Ikegami, T

    1976-09-01

    The steady state mode power distribution of the multimode graded index fiber was measured. A simple and effective steady state mode exciter was fabricated by an etching technique. Its insertion loss was 0.5 dB for an injection laser. Deviation in transmission characteristics of multimode graded index fibers can be avoided by using the steady state mode exciter.

  8. Photoionization of excited molecular states using multiphoton excitation techniques

    International Nuclear Information System (INIS)

    Dehmer, P.M.; Pratt, S.T.; Dehmer, J.L.

    1984-01-01

    Photoelectron spectra are reported for three photon resonant, four photon ionization of H 2 via the B 1 Σ/sub u/ + , v = 7 (J = 2,4) and C 1 π/sub u'/, v = 0-4 (J = 1) levels and of N 2 via the o 3 1 π/sub u'/, v = 1,2, b 1 π/sub u'/, v = 3-5, and c 1 π/sub u'/, v = 0 levels. The results reflect both the spectroscopy and the dynamics of photoionization of excited molecular states and are discussed in terms of the selection rules for photoionization and the relative probabilities of photoionization from Rydberg and valence states. In some cases, in accordance with the Franck-Condon principle, the results demonstrate that resonant multiphoton ionization through Rydberg states may be a powerful technique for the production of electronic, vibrational, and rotational state selected ions. However, in other cases, systematic departures from Franck-Condon factors are observed, which reflect the more subtle dynamics of excited state photoionization. 23 references, 6 figures, 2 tables

  9. Low-lying excited states by constrained DFT

    Science.gov (United States)

    Ramos, Pablo; Pavanello, Michele

    2018-04-01

    Exploiting the machinery of Constrained Density Functional Theory (CDFT), we propose a variational method for calculating low-lying excited states of molecular systems. We dub this method eXcited CDFT (XCDFT). Excited states are obtained by self-consistently constraining a user-defined population of electrons, Nc, in the virtual space of a reference set of occupied orbitals. By imposing this population to be Nc = 1.0, we computed the first excited state of 15 molecules from a test set. Our results show that XCDFT achieves an accuracy in the predicted excitation energy only slightly worse than linear-response time-dependent DFT (TDDFT), but without incurring into problems of variational collapse typical of the more commonly adopted ΔSCF method. In addition, we selected a few challenging processes to test the limits of applicability of XCDFT. We find that in contrast to TDDFT, XCDFT is capable of reproducing energy surfaces featuring conical intersections (azobenzene and H3) with correct topology and correct overall energetics also away from the intersection. Venturing to condensed-phase systems, XCDFT reproduces the TDDFT solvatochromic shift of benzaldehyde when it is embedded by a cluster of water molecules. Thus, we find XCDFT to be a competitive method among single-reference methods for computations of excited states in terms of time to solution, rate of convergence, and accuracy of the result.

  10. USING MAGNETIC MOMENTS TO UNVEIL THE NUCLEAR STRUCTURE OF LOW-SPIN NUCLEAR STATES

    Directory of Open Access Journals (Sweden)

    Diego A. Torres

    2011-07-01

    Full Text Available The experimental study of magnetic moments for nuclear states near the ground state, I ≤ 2, provides a powerful tool to test nuclear structure models. Traditionally, the use of Coulomb excitation reactions has been used to study low spin states, mostly I = 2. The use of alternative reaction channels, such as α transfer, for the production of radioactive species that, otherwise, will be only produced in future radioactive beam facilities has proved to be an alternative to measure not only excited states with I > 2, but to populate and study long-live radioactive nuclei. This contribution will present the experimental tools and challenges for the use of the transient field technique for the measurement of g factors in nuclear states with I ≤ 2, using Coulomb excitation and α-transfer reactions. Recent examples of experimental results near the N = 50 shell closure, and the experimental challenges for future implementations with radioactive beams, will be discussed.

  11. Electronic properties of excited states in single InAs quantum dots; Elektronische Struktur angeregter Zustaende einzelner InAs-Quantenpunkte

    Energy Technology Data Exchange (ETDEWEB)

    Warming, Till

    2009-02-20

    The application of quantum-mechanical effects in semiconductor nanostructures enables the realization of novel opto-electronic devices. Examples are given by single-photon emitters and emitters of entangled photon pairs, both being essential for quantum cryptography, or for qubit systems as needed for quantum computing. InAs/GaAs quantum dots are one of the most promising candidates for such applications. A detailed knowledge of the electronic properties of quantum dots is a prerequisite for this development. The aim of this work is an experimental access to the detailed electronic structure of the excited states in single InAs/GaAs quantum dots including few-particle effects and in particular exchange interaction. The experimental approach is micro photoluminescence excitation spectroscopy ({mu}PLE). One of the main difficulties using {mu}PLE to probe single QDs is the unambiguous assignment of the observed resonances in the spectrum to specific transitions. By comparing micro photoluminescence ({mu}PL) and {mu}PLE spectra, the identification of the main resonances becomes possible. The key is given by the fine structure of the hot trion. Excitation spectroscopy on single charged QDs enables for the first time the complete observation of a non-trivial fine structure of an excitonic complex in a QD, the hot trion. Modelling based on eight-band k.p theory in combination with a configuration interaction scheme is in excellent agreement. Therewith the simulation also enables realistic predictions on the fine structure of the ground-state exciton which is of large importance for single quantum dot devices. Theory concludes from the observed transitions that the structural symmetry of the QDs is broken. Micro photoluminescence excitation spectroscopy combined with resonantly excited micro photoluminescence enables an optical access to the single particle states of the hole without the influence of few-particle coulomb interactions. Based on this knowledge the exciton

  12. Localized excitations and the geometry of the 1nπ* excited states of pyrazine

    International Nuclear Information System (INIS)

    Kleier, D.A.; Martin, R.L.; Wadt, W.R.; Moomaw, W.R.

    1982-01-01

    Previous theoretical work has shown that the lowest excited singlet state of pyrazine, the π* 1 B 3 u state, is best described in terms of interacting excitations localized on each nitrogen. The present work refines the localized excitation model and considers its implications for the geometry of the 1 B 3 u state. Hartree-Fock calculations show that the best single configuration description of the nπ* state has broken ( 1 B 1 ) symmetry with the excitation strongly localized at one end of the molcule. If the symmetry-restricted hf result is used for reference, this localization describes an important correlation effect. The excited-state geometry was probed using configuration interaction wave functions based on the symmetry-restricted orbitals, as well as properly symmetrized ''valance-bond'' wave functions based on the broken symmetry solutions. Both descriptions lead to a very flat potential for a b/sub 1u/ vibrational mode. This mode reduces the molecular geometry from D/sub 2h/ to C/sub 2v/. We present spectroscopic evidence of our own and of other workers which is consistent with such a flat potential

  13. Rydberg energies using excited state density functional theory

    International Nuclear Information System (INIS)

    Cheng, C.-L.; Wu Qin; Van Voorhis, Troy

    2008-01-01

    We utilize excited state density functional theory (eDFT) to study Rydberg states in atoms. We show both analytically and numerically that semilocal functionals can give quite reasonable Rydberg energies from eDFT, even in cases where time dependent density functional theory (TDDFT) fails catastrophically. We trace these findings to the fact that in eDFT the Kohn-Sham potential for each state is computed using the appropriate excited state density. Unlike the ground state potential, which typically falls off exponentially, the sequence of excited state potentials has a component that falls off polynomially with distance, leading to a Rydberg-type series. We also address the rigorous basis of eDFT for these systems. Perdew and Levy have shown using the constrained search formalism that every stationary density corresponds, in principle, to an exact stationary state of the full many-body Hamiltonian. In the present context, this means that the excited state DFT solutions are rigorous as long as they deliver the minimum noninteracting kinetic energy for the given density. We use optimized effective potential techniques to show that, in some cases, the eDFT Rydberg solutions appear to deliver the minimum kinetic energy because the associated density is not pure state v-representable. We thus find that eDFT plays a complementary role to constrained DFT: The former works only if the excited state density is not the ground state of some potential while the latter applies only when the density is a ground state density.

  14. Phases and amplitudes for a modified repulsive Coulomb field

    International Nuclear Information System (INIS)

    Chidichimo, M.C.; Davison, T.S.

    1990-01-01

    The asymptotic form of the radial wave function for positive-energy states is calculated for the case of a repulsive Coulomb field. The cases of a pure Coulomb potential and a modified Coulomb potential are considered. Second-order analytic solutions for the amplitudes and phases are obtained when the modifications to the pure Coulombic potential take the form αr -2 +βr -3 +γr -4 , using the Jeffreys or WKB method. For the case of a pure Coulomb field, numerical results obtained from this method were compared with ''exact'' numerical results that were obtained using the analytic properties of the Coulomb wave functions. Tables are presented to show the conditions under which the method is accurate

  15. Scattering states of the Klein-Gordon equation with Coulomb-like scalar plus vector potentials in arbitrary dimension

    International Nuclear Information System (INIS)

    Chen Changyuan; Sun Dongsheng; Lu Falin

    2004-01-01

    Properties of scattering states of the Klein-Gordon equation with Coulomb-like scalar plus vector potentials are investigated in an arbitrary dimension. Exact results of normalized wave functions of scattering states in the 'k/2π scale' and formula of phase shifts are presented

  16. Structure and Spectrum of Dust Coulomb Clusters

    International Nuclear Information System (INIS)

    Cheung, F.M.H.; Ford, C.; Barkby, S.; Samarian, A.A.; Vladimirov, S.V.

    2005-01-01

    In our study, the dynamics of Coulomb cluster systems were simulated for different number of particles. The spectra of energy states of dust Coulomb clusters corresponding to various packing sequences were obtained. The broadening of the spectrum due to inter-ring twist was discovered. It was found that the inter-ring twist will lead to a change in the energy spectrum of Coulomb cluster. This change was accompanied by a distortion of stable shells such that particles are able to compensate for any additional Coulomb energy (owing to the inter-ring twist) by further reducing their radial distance as much as possible. The overall effect is a change in the shape of the outer-shell from circular to elliptical

  17. Higgs transition from a magnetic Coulomb liquid to a ferromagnet in Yb2Ti2O7

    Science.gov (United States)

    Chang, Lieh-Jeng; Onoda, Shigeki; Su, Yixi; Kao, Ying-Jer; Tsuei, Ku-Ding; Yasui, Yukio; Kakurai, Kazuhisa; Lees, Martin Richard

    2012-01-01

    In a class of frustrated magnets known as spin ice, magnetic monopoles emerge as classical defects and interact via the magnetic Coulomb law. With quantum-mechanical interactions, these magnetic charges are carried by fractionalized bosonic quasi-particles, spinons, which can undergo Bose–Einstein condensation through a first-order transition via the Higgs mechanism. Here, we report evidence of a Higgs transition from a magnetic Coulomb liquid to a ferromagnet in single-crystal Yb2Ti2O7. Polarized neutron scattering experiments show that the diffuse [111]-rod scattering and pinch-point features, which develop on cooling are suddenly suppressed below TC~0.21 K, where magnetic Bragg peaks and a full depolarization of the neutron spins are observed with thermal hysteresis, indicating a first-order ferromagnetic transition. Our results are explained on the basis of a quantum spin-ice model, whose high-temperature phase is effectively described as a magnetic Coulomb liquid, whereas the ground state shows a nearly collinear ferromagnetism with gapped spin excitations. PMID:22871811

  18. The triplet excited state of Bodipy: formation, modulation and application.

    Science.gov (United States)

    Zhao, Jianzhang; Xu, Kejing; Yang, Wenbo; Wang, Zhijia; Zhong, Fangfang

    2015-12-21

    Boron dipyrromethene (Bodipy) is one of the most extensively investigated organic chromophores. Most of the investigations are focused on the singlet excited state of Bodipy, such as fluorescence. In stark contrast, the study of the triplet excited state of Bodipy is limited, but it is an emerging area, since the triplet state of Bodipy is tremendously important for several areas, such as the fundamental photochemistry study, photodynamic therapy (PDT), photocatalysis and triplet-triplet annihilation (TTA) upconversion. The recent developments in the study of the production, modulation and application of the triplet excited state of Bodipy are discussed in this review article. The formation of the triplet state of Bodipy upon photoexcitation, via the well known approach such as the heavy atom effect (including I, Br, Ru, Ir, etc.), and the new methods, such as using a spin converter (e.g. C60), charge recombination, exciton coupling and the doubly substituted excited state, are summarized. All the Bodipy-based triplet photosensitizers show strong absorption of visible or near IR light and the long-lived triplet excited state, which are important for the application of the triplet excited state in PDT or photocatalysis. Moreover, the methods for switching (or modulation) of the triplet excited state of Bodipy were discussed, such as those based on the photo-induced electron transfer (PET), by controlling the competing Förster-resonance-energy-transfer (FRET), or the intermolecular charge transfer (ICT). Controlling the triplet excited state will give functional molecules such as activatable PDT reagents or molecular devices. It is worth noting that switching of the singlet excited state and the triplet state of Bodipy may follow different principles. Application of the triplet excited state of Bodipy in PDT, hydrogen (H2) production, photoredox catalytic organic reactions and TTA upconversion were discussed. The challenges and the opportunities in these areas were

  19. Vibronic coupling in the excited-states of carotenoids

    Energy Technology Data Exchange (ETDEWEB)

    Miki, Takeshi [Physikalisch-Chemisches Institut; Ruprecht-Karls-Universität Heidelberg; D-69120 Heidelberg; Germany; Buckup, Tiago [Physikalisch-Chemisches Institut; Ruprecht-Karls-Universität Heidelberg; D-69120 Heidelberg; Germany; Krause, Marie S. [Physikalisch-Chemisches Institut; Ruprecht-Karls-Universität Heidelberg; D-69120 Heidelberg; Germany; Southall, June [College of Medical; Veterinary, and Life Science; University of Glasgow; G12 8QQ Glasgow; UK; Cogdell, Richard J. [College of Medical; Veterinary, and Life Science; University of Glasgow; G12 8QQ Glasgow; UK; Motzkus, Marcus [Physikalisch-Chemisches Institut; Ruprecht-Karls-Universität Heidelberg; D-69120 Heidelberg; Germany

    2016-01-01

    The ultrafast femtochemistry of carotenoids is governed by the interaction between electronic excited states, which has been explained by the relaxation dynamics within a few hundred femtoseconds from the lowest optically allowed excited state S2to the optically dark state S1.

  20. Nucleon transfer reactions to rotational states induced by 206,208PB projectiles

    International Nuclear Information System (INIS)

    Wollersheim, H.J.; DeBoer, F.W.N.; Emling, H.; Grein, H.; Grosse, E.; Spreng, W.; Eckert, G.; Elze, Th.W.; Stelzer, K.; Lauterbach, Ch.

    1986-01-01

    In a systematic study of nucleon transfer reactions accompanied by Coulomb excitation the authors bombarded 152 Sm, 160 Gd and 232 Th with 206, 208 Pb beams at incident energies close to the Coulomb barrier. Particle-gamma coincidence techniques were used to identify excited states of reaction products populated through inelastic scattering and in nucleon transfer reactions. Large cross sections were observed for one- and two-neutron pick-up from 232 Th at an incident energy of 6.4 MeV/μ. The results are analyzed in the framework of semiclassical models

  1. Study of the effect of shell stabilization of the collective isovector valence-shell excitations along the N=80 isotonic chain

    CERN Multimedia

    Blazhev, A A; Kruecken, R; Coquard, L; Bloch, T P; Wadsworth, R; Danchev, M T; Jenkins, D G; Kroell, T; Leske, J

    It is proposed to initiate an experimental program to study the quadrupole-collective isovector valence-shell excitations the so-called mixed-symmetry states (MSSs) of unstable nuclei from the N = 80 isotonic chain. The main aim of this program is to investigate the microscopic mechanism which leads to a concentration or a fragmentation of the MSSs, an effect dubbed $\\textit{shell stabilization}$ of MSSs. This will be achieved by identification of MSSs of the unstable nuclei $^{140}$Nd and $^{142}$Sm. The MSSs of these nuclei will be identified experimentally by measuring their relative populations with respect to the population of the first 2$^{+}$ states in inverse kinematics Coulomb excitation (CE) reactions on light targets. As a first step of this program we apply for a beam time for the radioactive $^{140}$Nd and $^{142}$Sm beams at beam energy of 2.85 MeV/u. These beams will be used to determine the absolute B(E2;2$_{1}^{+} \\rightarrow$ 0$_{1}^{+}$) values for $^{140}$Nd and $^{142}$Sm in Coulomb excit...

  2. Rearrangements in ground and excited states

    CERN Document Server

    de Mayo, Paul

    1980-01-01

    Rearrangements in Ground and Excited States, Volume 3 presents essays on the chemical generation of excited states; the cis-trans isomerization of olefins; and the photochemical rearrangements in trienes. The book also includes essays on the zimmerman rearrangements; the photochemical rearrangements of enones; the photochemical rearrangements of conjugated cyclic dienones; and the rearrangements of the benzene ring. Essays on the photo rearrangements via biradicals of simple carbonyl compounds; the photochemical rearrangements involving three-membered rings or five-membered ring heterocycles;

  3. Excitation of lowest electronic states of thymine by slow electrons

    Science.gov (United States)

    Chernyshova, I. V.; Kontros, E. J.; Markush, P. P.; Shpenik, O. B.

    2013-11-01

    Excitation of lowest electronic states of the thymine molecules in the gas phase is studied by elec- tron energy loss spectroscopy. In addition to dipole-allowed transitions to singlet states, transitions to the lowest triplet states were observed. The low-energy features of the spectrum at 3.66 and 4.61 eV are identified with the excitation of the first triplet states 13 A' (π → π*) and 13 A″ ( n → π*). The higher-lying features at 4.96, 5.75, 6.17, and 7.35 eV are assigned mainly to the excitation of the π → π* transitions to the singlet states of the molecule. The excitation dynamics of the lowest states is studied. It is found that the first triplet state 13 A'(π → π*) is most efficiently excited at a residual energy close to zero, while the singlet 21 A'(π → π*) state is excited with almost identical efficiency at different residual energies.

  4. Electron-impact excitation and ionization cross sections for ground state and excited helium atoms

    International Nuclear Information System (INIS)

    Ralchenko, Yu.; Janev, R.K.; Kato, T.; Fursa, D.V.; Bray, I.; Heer, F.J. de

    2008-01-01

    Comprehensive and critically assessed cross sections for the electron-impact excitation and ionization of ground state and excited helium atoms are presented. All states (atomic terms) with n≤4 are treated individually, while the states with n≥5 are considered degenerate. For the processes involving transitions to and from n≥5 levels, suitable cross section scaling relations are presented. For a large number of transitions, from both ground and excited states, convergent close coupling calculations were performed to achieve a high accuracy of the data. The evaluated/recommended cross section data are presented by analytic fit functions, which preserve the correct asymptotic behavior of the cross sections. The cross sections are also displayed in graphical form

  5. Singlet-triplet splittings from the virial theorem and single-particle excitation energies

    Science.gov (United States)

    Becke, Axel D.

    2018-01-01

    The zeroth-order (uncorrelated) singlet-triplet energy difference in single-particle excited configurations is 2Kif, where Kif is the Coulomb self-energy of the product of the transition orbitals. Here we present a non-empirical, virial-theorem argument that the correlated singlet-triplet energy difference should be half of this, namely, Kif. This incredibly simple result gives vertical HOMO-LUMO excitation energies in small-molecule benchmarks as good as the popular TD-B3LYP time-dependent approach to excited states. For linear acenes and nonlinear polycyclic aromatic hydrocarbons, the performance is significantly better than TD-B3LYP. In addition to the virial theorem, the derivation borrows intuitive pair-density concepts from density-functional theory.

  6. Coulomb disintegration as an information source for relevant processes in nuclear astrophysics

    International Nuclear Information System (INIS)

    Bertulani, C.A.

    1989-01-01

    The possibility of obtaining the photodisintegration cross section using the equivalent-photon number method first deduced and employed for the Coulomb disintegration processes has been suggested. This is very interesting because there exist radioactive capture processes, related to the photodisintegration through time reversal, that are relevant in astrophysics. In this paper, the recent results of the Karlsruhe and the Texas A and M groups on the Coulomb disintegration of 6 Li and 7 Li and the problems of the method are discussed. The ideas developed in a previous paper (Nucl. Phys. A458 (1986) 188) are confirmed qualitatively. To understand the process quantitatively it is necessary to use a quantum treatment that would imply the introduction of Coulomb excitation effects of higher orders. The Coulomb disintegration of exotic secondary beams is also studied. It is particularly interesting the question about what kind of nuclear structure information, as binding energies of momentum distributions, may be obtained. (Author) [es

  7. Coulomb Mediated Hybridization of Excitons in Coupled Quantum Dots.

    Science.gov (United States)

    Ardelt, P-L; Gawarecki, K; Müller, K; Waeber, A M; Bechtold, A; Oberhofer, K; Daniels, J M; Klotz, F; Bichler, M; Kuhn, T; Krenner, H J; Machnikowski, P; Finley, J J

    2016-02-19

    We report Coulomb mediated hybridization of excitonic states in optically active InGaAs quantum dot molecules. By probing the optical response of an individual quantum dot molecule as a function of the static electric field applied along the molecular axis, we observe unexpected avoided level crossings that do not arise from the dominant single-particle tunnel coupling. We identify a new few-particle coupling mechanism stemming from Coulomb interactions between different neutral exciton states. Such Coulomb resonances hybridize the exciton wave function over four different electron and hole single-particle orbitals. Comparisons of experimental observations with microscopic eight-band k·p calculations taking into account a realistic quantum dot geometry show good agreement and reveal that the Coulomb resonances arise from broken symmetry in the artificial semiconductor molecule.

  8. Extensive degeneracy, Coulomb phase and magnetic monopoles in artificial square ice.

    Science.gov (United States)

    Perrin, Yann; Canals, Benjamin; Rougemaille, Nicolas

    2016-12-15

    Artificial spin-ice systems are lithographically patterned arrangements of interacting magnetic nanostructures that were introduced as way of investigating the effects of geometric frustration in a controlled manner. This approach has enabled unconventional states of matter to be visualized directly in real space, and has triggered research at the frontier between nanomagnetism, statistical thermodynamics and condensed matter physics. Despite efforts to create an artificial realization of the square-ice model-a two-dimensional geometrically frustrated spin-ice system defined on a square lattice-no simple geometry based on arrays of nanomagnets has successfully captured the macroscopically degenerate ground-state manifold of the model. Instead, square lattices of nanomagnets are characterized by a magnetically ordered ground state that consists of local loop configurations with alternating chirality. Here we show that all of the characteristics of the square-ice model are observed in an artificial square-ice system that consists of two sublattices of nanomagnets that are vertically separated by a small distance. The spin configurations we image after demagnetizing our arrays reveal unambiguous signatures of a Coulomb phase and algebraic spin-spin correlations, which are characterized by the presence of 'pinch' points in the associated magnetic structure factor. Local excitations-the classical analogues of magnetic monopoles-are free to evolve in an extensively degenerate, divergence-free vacuum. We thus provide a protocol that could be used to investigate collective magnetic phenomena, including Coulomb phases and the physics of ice-like materials.

  9. Coulomb singularity effects in tunnelling spectroscopy of individual impurities

    OpenAIRE

    Arseyev, P. I.; Maslova, N. S.; Panov, V. I.; Savinov, S. V.

    2002-01-01

    Non-equilibrium Coulomb effects in resonant tunnelling processes through deep impurity states are analyzed. It is shown that Coulomb vertex corrections to the tunnelling transfer amplitude lead to a power-law singularity in current- voltage characteristics

  10. Study of a Quantum Dot in an Excited State

    Science.gov (United States)

    Slamet, Marlina; Sahni, Viraht

    We have studied the first excited singlet state of a quantum dot via quantal density functional theory (QDFT). The quantum dot is represented by a 2D Hooke's atom in an external magnetostatic field. The QDFT mapping is from an excited singlet state of this interacting system to one of noninteracting fermions in a singlet ground state. The results of the study will be compared to (a) the corresponding mapping from a ground state of the quantum dot and (b) to the similar mapping from an excited singlet state of the 3D Hooke's atom.

  11. Gyromagnetic ratios of low-lying excited states in the even 192-198Pt isotopes; experimental measurements and theoretical predictions

    International Nuclear Information System (INIS)

    Stuchbery, A.E.; Ryan, C.G.; Morrison, I.; Bolotin, H.H.

    1981-01-01

    The gyromagnetic ratios of the 2 2 + and 4 1 + states in 196 Pt were measured relative to that of its 2 1 + level. The thin-foil IMPAC technique was employed utilizing the enhanced transient hyperfine magnetic field present at the nuclei of swiftly recoiling ions traversing magnetized ferromagetic materials. The states of interest were populated by Coulomb excitation using beams of 220-MeV 58 Ni ions. For g(2 1 + ) taken as 0.326+-0.014, the present measurements yielded g(2 2 + ) = 0.30+-0.06 and g(4 1 + ) 0.30+-0.05. These results and those reported by prior workers for the g-factors of corresponding levels in 192 Pt, 194 Pt, 198 Pt are used to trace the systematics of the magnetic moments of these low-lying levels in the even 192 - 198 Pt isotopes. Interacting Boson Approximation model-based calculations of the g-factors of these states were also carried out. The experimental theoretical results are compared

  12. Observation of a structural transition for coulomb crystals in a linear Paul trap

    DEFF Research Database (Denmark)

    Kjærgaard, N.; Drewsen, M.

    2003-01-01

    A structural transition for laser cooled ion Coulomb crystals in a linear Paul trap just above the stability limit of parametrically resonant excitation of bulk plasma modes has been observed. In contrast to the usual spheroidal shell structures present below the stability limit, the ions arrange...... in a "string-of-disks" configuration. The spheroidal envelopes of the string-of-disks structures are in agreement with results from cold fluid theory usually valid for ion Coulomb crystals if the ion systems are assumed to be rotating collectively....

  13. Observation of a structural transition for Coulomb crystals in a linear Paul trap

    International Nuclear Information System (INIS)

    Kjaergaard, Niels; Drewsen, Michael

    2003-01-01

    A structural transition for laser cooled ion Coulomb crystals in a linear Paul trap just above the stability limit of parametrically resonant excitation of bulk plasma modes has been observed. In contrast to the usual spheroidal shell structures present below the stability limit, the ions arrange in a 'string-of-disks' configuration. The spheroidal envelopes of the string-of-disks structures are in agreement with results from cold fluid theory usually valid for ion Coulomb crystals if the ion systems are assumed to be rotating collectively

  14. Ultrafast excited-state dynamics of 2,5-dimethylpyrrole.

    Science.gov (United States)

    Yang, Dongyuan; Min, Yanjun; Chen, Zhichao; He, Zhigang; Yuan, Kaijun; Dai, Dongxu; Yang, Xueming; Wu, Guorong

    2018-04-17

    The ultrafast excited-state dynamics of 2,5-dimethylpyrrole following excitation at wavelengths in the range of 265.7-216.7 nm is studied using the time-resolved photoelectron imaging method. It is found that excitation at longer wavelengths (265.7-250.2 nm) results in the population of the S1(1πσ*) state, which decays out of the photoionization window in about 90 fs. At shorter pump wavelengths (242.1-216.7 nm), the assignments are less clear-cut. We tentatively assign the initially photoexcited state(s) to the 1π3p Rydberg state(s) which has lifetimes of 159 ± 20, 125 ± 15, 102 ± 10 and 88 ± 10 fs for the pump wavelengths of 242.1, 238.1, 232.6 and 216.7 nm, respectively. Internal conversion to the S1(1πσ*) state represents at most a minor decay channel. The methyl substitution effects on the decay dynamics of the excited states of pyrrole are also discussed. Methyl substitution on the pyrrole ring seems to enhance the direct internal conversion from the 1π3p Rydberg state to the ground state, while methyl substitution on the N atom has less influence and the internal conversion to the S1(πσ*) state represents a main channel.

  15. Coulomb couplings in solubilised light harvesting complex II (LHCII): challenging the ideal dipole approximation from TDDFT calculations.

    Science.gov (United States)

    López-Tarifa, P; Liguori, Nicoletta; van den Heuvel, Naudin; Croce, Roberta; Visscher, Lucas

    2017-07-19

    The light harvesting complex II (LHCII), is a pigment-protein complex responsible for most of the light harvesting in plants. LHCII harvests sunlight and transfers excitation energy to the reaction centre of the photo-system, where the water oxidation process takes place. The energetics of LHCII can be modulated by means of conformational changes allowing a switch from a harvesting to a quenched state. In this state, the excitation energy is no longer transferred but converted into thermal energy to prevent photooxidation. Based on molecular dynamics simulations at the microsecond time scale, we have recently proposed that the switch between different fluorescent states can be probed by correlating shifts in the chromophore-chromophore Coulomb interactions to particular protein movements. However, these findings are based upon calculations in the ideal point dipole approximation (IDA) where the Coulomb couplings are simplified as first order dipole-dipole interactions, also assuming that the chromophore transition dipole moments lay in particular directions of space with constant moduli (FIX-IDA). In this work, we challenge this approximation using the time-dependent density functional theory (TDDFT) combined with the frozen density embedding (FDE) approach. Our aim is to establish up to which limit FIX-IDA can be applied and which chromophore types are better described under this approximation. For that purpose, we use the classical trajectories of solubilised light harvesting complex II (LHCII) we have recently reported [Liguori et al., Sci. Rep., 2015, 5, 15661] and selected three pairs of chromophores containing chlorophyll and carotenoids (Chl and Car): Chla611-Chla612, Chlb606-Chlb607 and Chla612-Lut620. Using the FDE in the Tamm-Dancoff approximation (FDEc-TDA), we show that IDA is accurate enough for predicting Chl-Chl Coulomb couplings. However, the FIX-IDA largely overestimates Chl-Car interactions mainly because the transition dipole for the Cars is not

  16. Electronically excited negative ion resonant states in chloroethylenes

    Energy Technology Data Exchange (ETDEWEB)

    Khvostenko, O.G., E-mail: khv@mail.ru; Lukin, V.G.; Tuimedov, G.M.; Khatymova, L.Z.; Kinzyabulatov, R.R.; Tseplin, E.E.

    2015-02-15

    Highlights: • Several novel dissociative negative ion channels were revealed in chloroethylenes. • The electronically excited resonant states were recorded in all chloroethylenes under study. • The states were assigned to the inter-shell types, but not to the core-excited Feshbach one. - Abstract: The negative ion mass spectra of the resonant electron capture by molecules of 1,1-dichloroethylene, 1,2-dichloroethylene-cis, 1,2-dichloroethylene-trans, trichloroethylene and tetrachloroethylene have been recorded in the 0–12 eV range of the captured electron energy using static magnetic sector mass spectrometer modified for operation in the resonant electron capture regime. As a result, several novel low-intensive dissociation channels were revealed in the compounds under study. Additionally, the negative ion resonant states were recorded at approximately 3–12 eV, mostly for the first time. These resonant states were assigned to the electronically excited resonances of the inter-shell type by comparing their energies with those of the parent neutral molecules triplet and singlet electronically excited states known from the energy-loss spectra obtained by previous studies.

  17. Trinucleon asymptotic normalization constants including Coulomb effects

    International Nuclear Information System (INIS)

    Friar, J.L.; Gibson, B.F.; Lehman, D.R.; Payne, G.L.

    1982-01-01

    Exact theoretical expressions for calculating the trinucleon S- and D-wave asymptotic normalization constants, with and without Coulomb effects, are presented. Coordinate-space Faddeev-type equations are used to generate the trinucleon wave functions, and integral relations for the asymptotic norms are derived within this framework. The definition of the asymptotic norms in the presence of the Coulomb interaction is emphasized. Numerical calculations are carried out for the s-wave NN interaction models of Malfliet and Tjon and the tensor force model of Reid. Comparison with previously published results is made. The first estimate of Coulomb effects for the D-wave asymptotic norm is given. All theoretical values are carefully compared with experiment and suggestions are made for improving the experimental situation. We find that Coulomb effects increase the 3 He S-wave asymptotic norm by less than 1% relative to that of 3 H, that Coulomb effects decrease the 3 He D-wave asymptotic norm by approximately 8% relative to that of 3 H, and that the distorted-wave Born approximation D-state parameter, D 2 , is only 1% smaller in magnitude for 3 He than for 3 H due to compensating Coulomb effects

  18. Ultrafast dynamics of Coulomb correlated excitons in GaAs quantum wells

    Energy Technology Data Exchange (ETDEWEB)

    Mycek, M.A. [Univ. of California, Berkeley, CA (United States). Dept. of Physics]|[Lawrence Berkeley National Lab., CA (United States). Materials Sciences Div.

    1995-12-01

    The author measures the transient nonlinear optical response of room temperature excitons in gallium arsenide quantum wells via multi-wave mixing experiments. The dynamics of the resonantly excited excitons is directly reflected by the ultrafast decay of the induced nonlinear polarization, which radiates the detected multi-wave mixing signal. She characterizes this ultrafast coherent emission in both amplitude and phase, using time- and frequency-domain measurement techniques, to better understand the role of Coulomb correlation in these systems. To interpret the experimental results, the nonlinear optical response of a dense medium is calculated using a model including Coulomb interaction. She contributes three new elements to previous theoretical and experimental studies of these systems. First, surpassing traditional time-integrated measurements, she temporally resolves the amplitude of the ultrafast coherent emission. Second, in addition to measuring the third-order four-wave mixing signal, she also investigates the fifth-order six-wave mixing response. Third, she characterizes the ultrafast phase dynamics of the nonlinear emission using interferometric techniques with an unprecedented resolution of approximately 140 attoseconds. The author finds that effects arising from Coulomb correlation dominate the nonlinear optical response when the density of excitons falls below 3 {times} 10{sup 11} cm{sup {minus}2}, the saturation density. These signatures of Coulomb correlation are investigated for increasing excitation density to gradually screen the interactions and test the validity of the model for dense media. The results are found to be qualitatively consistent with both the predictions of the model and with numerical solutions to the semiconductor Bloch equations. Importantly, the results also indicate current experimental and theoretical limitations, which should be addressed in future research.

  19. Dynamics in few body Coulomb problems

    International Nuclear Information System (INIS)

    Ovchinnikov, S.Y.; Macek, J.H.; Tantawi, R.S.; Sabbah, A.S.

    1999-01-01

    We develop the 'positive energy Sturmian technique' for the solution of time-dependent Schroedinger equations which describe few Coulomb centers with scattering initial conditions. The 'positive energy Sturmian technique' is based on the following main steps: (i) time-dependent scaled transformation; (ii) Fourier transformation into the frequency domain; (iii) outgoing wave Sturmian expansions; and (iv) solution of coupled equations. The technique has been applied in electron-atom and ion-atom collisions for calculations of energy and angular distributions of emitted electrons and excitations of atoms. Refs. 2 (author)

  20. Mapping the boundaries of the seniority regime and collective motion: Coulomb excitation studies of N = 122 isotones $^{206}$Po and $^{208}$Rn

    CERN Multimedia

    Butler, P; Voulot, D; Rahkila, P J; Darby, I G; Grahn, T; Bree, N C F; Julin, R J; Diriken, J V J; Jenkins, D G; Kroell, T; Huyse, M L

    In regions near magic nuclei, seniority can be regarded as a good quantum number. In the N = 122 isotones above the Z = 82 shell closure relative high-$\\textit{j}\\,$ single-particle proton orbitals dominate the structure and thus levels up to $\\textit{I}$ = 2$\\textit{j}$ - 1 could, in principle, be understood within the seniority scheme. While B(E2) values usually increase within the band with increasing $\\textit{I}$, the seniority scheme can lead to a contrasting result. The present proposal addresses this phenomenon through the measurements of previously unknown B(E2; 0$^{+}\\rightarrow$ 2$^{+}$) values in $^{206}$Po and $^{208}$Rn. The proposed Coulomb excitation measurements of radioactive beams will be carried out at the REX-ISOLDE facility using the MINIBALL $\\gamma$-ray spectrometer.

  1. Non local theory of excitations applied to the Hubbard model

    International Nuclear Information System (INIS)

    Kakehashi, Y; Nakamura, T; Fulde, P

    2010-01-01

    We propose a nonlocal theory of single-particle excitations. It is based on an off-diagonal effective medium and the projection operator method for treating the retarded Green function. The theory determines the nonlocal effective medium matrix elements by requiring that they are consistent with those of the self-energy of the Green function. This arrows for a description of long-range intersite correlations with high resolution in momentum space. Numerical study for the half-filled Hubbard model on the simple cubic lattice demonstrates that the theory is applicable to the strong correlation regime as well as the intermediate regime of Coulomb interaction strength. Furthermore the results show that nonlocal excitations cause sub-bands in the strong Coulomb interaction regime due to strong antiferromagnetic correlations, decrease the quasi-particle peak on the Fermi level with increasing Coulomb interaction, and shift the critical Coulomb interaction U C2 for the divergence of effective mass towards higher energies at least by a factor of two as compared with that in the single-site approximation.

  2. The Coulomb potential in quantum mechanics and related topics

    International Nuclear Information System (INIS)

    Haeringen, H. van.

    1978-01-01

    This dissertation consists of an analytic study of the Coulomb interaction in nonrelativistic quantum mechanics and some related topics. The author investigates in a number of self-contained articles various interesting and important properties of the Coulomb potential. Some of these properties are shared by other potentials which also play a role in quantum mechanics. For such related interactions a comparative study is made. The principal difficulties in the description of proton-deuteron scattering and break-up reactions, due to the Coulomb interaction, are studied by working out a simple model. The bound states are studied for the Coulomb plus Yamaguchi potential, for the symmetric shifted Coulomb potential, and for local potentials with an inverse-distance-squared asymptotic behaviour. (Auth.)

  3. Computing correct truncated excited state wavefunctions

    Science.gov (United States)

    Bacalis, N. C.; Xiong, Z.; Zang, J.; Karaoulanis, D.

    2016-12-01

    We demonstrate that, if a wave function's truncated expansion is small, then the standard excited states computational method, of optimizing one "root" of a secular equation, may lead to an incorrect wave function - despite the correct energy according to the theorem of Hylleraas, Undheim and McDonald - whereas our proposed method [J. Comput. Meth. Sci. Eng. 8, 277 (2008)] (independent of orthogonality to lower lying approximants) leads to correct reliable small truncated wave functions. The demonstration is done in He excited states, using truncated series expansions in Hylleraas coordinates, as well as standard configuration-interaction truncated expansions.

  4. Probability of collective excited state decay

    International Nuclear Information System (INIS)

    Manykin, Eh.A.; Ozhovan, M.I.; Poluehktov, P.P.

    1987-01-01

    Decay mechanisms of condensed excited state formed of highly excited (Rydberg) atoms are considered, i.e. stability of so-called Rydberg substance is analyzed. It is shown that Auger recombination and radiation transitions are the basic processes. The corresponding probabilities are calculated and compared. It is ascertained that the ''Rydberg substance'' possesses macroscopic lifetime (several seconds) and in a sense it is metastable

  5. Excited-state dynamics of pentacene derivatives with stable radical substituents.

    Science.gov (United States)

    Ito, Akitaka; Shimizu, Akihiro; Kishida, Noriaki; Kawanaka, Yusuke; Kosumi, Daisuke; Hashimoto, Hideki; Teki, Yoshio

    2014-06-23

    The excited-state dynamics of pentacene derivatives with stable radical substituents were evaluated in detail through transient absorption measurements. The derivatives showed ultrafast formation of triplet excited state(s) in the pentacene moiety from a photoexcited singlet state through the contributions of enhanced intersystem crossing and singlet fission. Detailed kinetic analyses for the transient absorption data were conducted to quantify the excited-state characteristics of the derivatives. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Excitation of nuclear states by synchrotron radiation

    International Nuclear Information System (INIS)

    Olariu, Albert

    2003-01-01

    We study the excitation of nuclear states by gamma ray beams of energy up to 200 keV produced as synchrotron radiation. We consider the possibility to populate an excited state |i> in two steps, from the ground state |g> to an intermediary state |n> which decays by gamma emission or internal conversion to a lower state |i>. The aim of this study is to establish that the probability P 2 of the two-step transition |g> → |n> → |i> should be greater than the probability P 1 of the direct transition |g> → |i>. The probabilities P 1 and P 2 correspond to a radiation pulse of duration equal to the half-time of the state |i>. We have written a computer program in C++ which computes the probability P 2 , the ratio P 2 /P 1 and the rate C 2 of the two-step transitions for any nuclei and different configurations of states. The program uses a database which contains information on the energy levels, half-lives, spins and parities of nuclear states and on the relative intensities of the nuclear transitions. If the half-lives or the relative intensities are not known the program uses the Weisskopf estimates for the transition half-lives. An interpolation program of internal conversion coefficients has also been used. We listed the values obtained for P 2 , P 2 /P 1 and C 2 in a number of cases in which P 2 is significant from the 2900 considered cases. The states |i> and |n> have the energies E i and E n , the corresponding half-lives being t i and t n . The spectral density of the synchrotron radiation has been considered to be 10 12 photons cm -2 s -1 eV -1 . We listed only the cases for which the relative intensities of the transitions from levels |n> and |i> to lower states are known. The calculations carried out in this study allowed us to identify nuclei for which P 2 has relatively great values. In the listed cases P 2 /P 1 >>1, so that the two-step excitation by synchrotron radiation is more efficient than the direct excitation |g> → |i>. For a sample having 10

  7. K-shell excitation studied for H- and He-like bismuth ions in collisions with low-z target atoms

    International Nuclear Information System (INIS)

    Stoehlker, T.; Bosch, F.; Geissel, H.; Kozhuharov, C.; Ludziejewski, T.; Mokler, P.H.; Scheidenberger, C.; Stachura, Z.; Warczak, A.

    1997-09-01

    The formation of excited projectile states via Coulomb excitation is investigated for hydrogen- and helium-like bismuth projectiles (Z=83) in relativistic ion-atom collisions. The excitation process was unambiguously identified by observing the radiative decay of the excited levels to the vacant 1s shell in coincidence with ions that did not undergo charge exchange in the reaction target. In particular, owing to the large fine structure splitting of Bi, the excitation cross-sections to the various L-shell sublevels are determined separately. The results are compared with detailed relativistic calculations, showing that both the relativistic character of the bound-state wave-functions and the magnetic interaction are of considerable importance for the K-shell excitation process in high-Z ions like Bi. The experimental data confirm the result of the complete relativistic calculations, namely that the magnetic part of the Lienard-Wiechert interaction leads to a significant reduction of the K-shell excitation cross-section. (orig.)

  8. Electron-lattice Interaction and Nonlinear Excitations in Cuprate Structures

    International Nuclear Information System (INIS)

    Paulsen, J.; Eschrig, H.; Drechsler, S.L.; Malek, J.

    1995-01-01

    A low temperature lattice modulation of the chains of the YBa 2 Cu 3 O 7 is considered by deriving a Hamiltonian of electron-lattice interaction from density-functional calculations for deformed lattice and solving it for the groundstate. Hubbard-type Coulomb interaction is included. The obtained groundstate is a charge-density-wave state with a pereodicity of four lattice constants and a gap for one-electron excitations of about 1eV, sensitively depending on parameters of the Hamiltonian. There are lots of polaronic and solitonic excitations with formation energies deep in the gap, which can pin the Fermi level and thus produce again metallicity of the chain. They might also contribute to pairing of holes in adjacent CuO 2 -planes. (author)

  9. Empirical Coulomb matrix elements and the mass of 22Al

    International Nuclear Information System (INIS)

    Whitehead, R.R.; Watt, A.; Kelvin, D.; Rutherford, H.J.

    1976-01-01

    An attempt has been made to obtain a set of Coulomb matrix elements which fit the known Coulomb energy shifts in the nuclei of mass 18 to 22. The interaction obtained fits the data well with only a few exceptions, one of these being the Coulomb shift of the notorious third 0 + state in 18 Ne. These Coulomb matrix elements are used together with the Chung-Wildenthal interaction to obtain a new prediction for the mass excess of 22 Al. The results indicate that 22 Al should be bound against proton emission. (Auth.)

  10. Exact solution of the N-dimensional generalized Dirac-Coulomb equation

    International Nuclear Information System (INIS)

    Tutik, R.S.

    1992-01-01

    An exact solution to the bound state problem for the N-dimensional generalized Dirac-Coulomb equation, whose potential contains both the Lorentz-vector and Lorentz-scalar terms of the Coulomb form, is obtained. 24 refs. (author)

  11. Influence of the Coulomb interaction in the final state on the cross section of single-electron capture by fast ions

    International Nuclear Information System (INIS)

    Novikov, N.V.; Teplova, Ya.A.

    2011-01-01

    It is shown that the Coulomb interaction of ions in the final state must be taken into account in the estimation of the cross section of electron capture by fast ions. The cross section of electron capture decreases considerably, and the dependence of the cross section on the collision energy becomes close to the experimental one if the interaction of charged particles after collision is taken into account. -- Highlights: → Coulomb interaction of ions in the final state must be taken into account. → This interaction leads to a considerable decrease in the cross section. → The dependence on energy close to the experimental one.

  12. Charge-carrier dynamics and Coulomb effects in semiconductor tetrapods

    International Nuclear Information System (INIS)

    Mauser, Christian

    2011-01-01

    In this thesis the Coulomb interaction and its influence on localization effects and dynamics of charge carriers in semiconductor nanocrystals were studied. In the studied nanostructures it deals with colloidal tetrapod heterostructures, which consist of a cadmium selenide (CdSe) core and four tetraedrical grown cadmium sulfide (CdS) respectively cadmium telluride (CdTe) legs, which exhibit a type-I respectively type-II band transition. The dynamics and interactions were studied by means of photoluminescence (PL) and absorption measurements both on the ensemble and on single nanoparticles, as well as time-resolved PL and transient absorption spectroscopy. Additionally theoretical simulations of the wave-function distributions were performed, which are based on the effective-mass approximation. The special band structure of the CdSe/CdS tetrapods offers a unique possibility to study the Coulomb interaction. The flat conduction band in these heterostructures makes the electron via the Coulomb interaction sensitive to the localization position of the hole within the structure. The valence band has instead a potential maximum in the CdSe, which leads to a directed localization of the hole and the photoluminescence of the core. Polarization-resolved measurements showed hereby an anisotropy of the photoluminescence, which could be explained by means of simulations of the wave-function distribution with an asymmetry at the branching point. Charge-carrier localization occur mainly both in longer structures and in trap states in the CdS leg and can be demonstrated in form of a dual emission from a nanocrystal. The charge-carrier dynamics of electron and hole in tetrapods is indeed coupled by the Coulomb interaction, however it cannot be completely described in an exciton picture. The coupled dynamics and the Coulomb interaction were studied concerning a possible influence of the geometry in CdSe/CdS nanorods and compared with those of the tetrapods. The interactions of the

  13. The formation and decay of triply excited He- states in e-He scattering

    International Nuclear Information System (INIS)

    Heideman, H.G.M.

    1988-01-01

    A description is given of doubly and triply excited negative-ion states and their effects on the electron impact excitation of atomic states. Mechanisms for indirect excitation of singly excited states are discussed with respect to:- negative-ion resonance, autoionisation and post-collision interaction, and excitation of an autoionising state via a negative ion resonance. A classification of doubly excited states is considered. Experimental results on the excitation of the n'S states of helium as a function of the incident electron energy are presented, along with theoretical PCI (post collision interaction) profiles in excitation functions, and an interpretation of the results. (UK)

  14. Excitation and decay of correlated atomic states

    International Nuclear Information System (INIS)

    Rau, A.R.P.

    1992-01-01

    Doubly excited states of atoms and ions in which two electrons are excited from the ground configuration display strong radial and angular electron correlations. They are prototypical examples of quantum-mechanical systems with strong coupling. Two distinguishing characteristics of these states are: (1) their organization into successive families, with only weak coupling between families, and (2) a hierarchical nature of this coupling, with states from one family decaying primarily to those in the next lower family. A view of the pair of electrons as a single entity, with the electron-electron repulsion between them divided into a adiabatic and nonadiabatic piece, accounts for many of the dominant features. The stronger, adiabatic part determines the family structure and the weaker, nonadiabatic part the excitation and decay between successive families. Similar considerations extend to three-electron atomic states, which group into five different classes. They are suggestive of composite models for quarks in elementary particle physics, which exhibit analogous groupings into families with a hierarchical arrangement of masses and electroweak decays. 49 refs., 6 figs., 2 tabs

  15. Electron capture and excitation processes in H+-H collisions in dense quantum plasmas

    Science.gov (United States)

    Jakimovski, D.; Markovska, N.; Janev, R. K.

    2016-10-01

    Electron capture and excitation processes in proton-hydrogen atom collisions taking place in dense quantum plasmas are studied by employing the two-centre atomic orbital close-coupling (TC-AOCC) method. The Debye-Hückel cosine (DHC) potential is used to describe the plasma screening effects on the Coulomb interaction between charged particles. The properties of a hydrogen atom with DHC potential are investigated as a function of the screening strength of the potential. It is found that the decrease in binding energy of nl levels with increasing screening strength is considerably faster than in the case of the Debye-Hückel (DH) screening potential, appropriate for description of charged particle interactions in weakly coupled classical plasmas. This results in a reduction in the number of bound states in the DHC potential with respect to that in the DH potential for the same plasma screening strength, and is reflected in the dynamics of excitation and electron capture processes for the two screened potentials. The TC-AOCC cross sections for total and state-selective electron capture and excitation cross sections with the DHC potential are calculated for a number of representative screening strengths in the 1-300 keV energy range and compared with those for the DH and pure Coulomb potential. The total capture cross sections for a selected number of screening strengths are compared with the available results from classical trajectory Monte Carlo calculations.

  16. Alpha particles-and 3He inelastic scattering by 124Sn in the coulomb barrier region

    International Nuclear Information System (INIS)

    Appoloni, C.R.

    1976-01-01

    Angular distributions for inelastic scattering of α and 3 He particles in 124 Sn at the incident energies around Coulomb barrier were measured using the 8UD Pelletron Tandem Accelerator of The University of Sao Paulo. The results were analysed by DWBA with a collective form factor including the effects due to the interference between coulomb and nuclear excitations with the code PATIWEN (Ba75). The nuclear deformation parameters for the one phonon levels (2 + and 3 - ) have been obtained. (Author) [pt

  17. Sub-50 fs excited state dynamics of 6-chloroguanine upon deep ultraviolet excitation.

    Science.gov (United States)

    Mondal, Sayan; Puranik, Mrinalini

    2016-05-18

    The photophysical properties of natural nucleobases and their respective nucleotides are ascribed to the sub-picosecond lifetime of their first singlet states in the UV-B region (260-350 nm). Electronic transitions of the ππ* type, which are stronger than those in the UV-B region, lie at the red edge of the UV-C range (100-260 nm) in all isolated nucleobases. The lowest energetic excited states in the UV-B region of nucleobases have been investigated using a plethora of experimental and theoretical methods in gas and solution phases. The sub-picosecond lifetime of these molecules is not a general attribute of all nucleobases but specific to the five primary nucleobases and a few xanthine and methylated derivatives. To determine the overall UV photostability, we aim to understand the effect of more energetic photons lying in the UV-C region on nucleobases. To determine the UV-C initiated photophysics of a nucleobase system, we chose a halogen substituted purine, 6-chloroguanine (6-ClG), that we had investigated previously using resonance Raman spectroscopy. We have performed quantitative measurements of the resonance Raman cross-section across the Bb absorption band (210-230 nm) and constructed the Raman excitation profiles. We modeled the excitation profiles using Lee and Heller's time-dependent theory of resonance Raman intensities to extract the initial excited state dynamics of 6-ClG within 30-50 fs after photoexcitation. We found that imidazole and pyrimidine rings of 6-ClG undergo expansion and contraction, respectively, following photoexcitation to the Bb state. The amount of distortions of the excited state structure from that of the ground state structure is reflected by the total internal reorganization energy that is determined at 112 cm(-1). The contribution of the inertial component of the solvent response towards the total reorganization energy was obtained at 1220 cm(-1). In addition, our simulation also yields an instantaneous response of the first

  18. Eikonal representation of N-body Coulomb scattering amplitudes

    International Nuclear Information System (INIS)

    Fried, H.M.; Kang, K.; McKellar, B.H.J.

    1983-01-01

    A new technique for the construction of N-body Coulomb scattering amplitudes is proposed, suggested by the simplest case of N = 2: Calculate the scattering amplitude in eikonal approximation, discard the infinite phase factors which appear upon taking the limit of a Coulomb potential, and treat the remainder as an amplitude whose absolute value squared produces the exact, Coulomb differential cross section. The method easily generalizes to the N-body Coulomb problem for elastic scattering, and for inelastic rearrangement scattering of Coulomb bound states. We give explicit results for N = 3 and 4; in the N = 3 case we extract amplitudes for the processes (12)+3->1+2+3 (breakup), (12)+3->1+(23) (rearrangement), and (12)+3→(12)'+3 (inelastic scattering) as residues at the appropriate poles in the free-free amplitude. The method produces scattering amplitudes f/sub N/ given in terms of explicit quadratures over (N-2) 2 distinct integrands

  19. Excitation of autoionizing states of helium by 100 keV proton impact: II. Excitation cross sections and mechanisms of excitation

    Energy Technology Data Exchange (ETDEWEB)

    Godunov, A.L. [Department of Physics, Tulane University, New Orleans, LA 70118-5698 (United States); Ivanov, P.B.; Schipakov, V.A. [Troitsk Institute of Innovation and Fusion Research Troitsk, Moscow region, 142092 (Russian Federation); Moretto-Capelle, P.; Bordenave-Montesquieu, D.; Bordenave-Montesquieu, A. [Laboratoire Collisions, Agregats, Reactivite, IRSAMC, UMR 5589, CNRS-Universite Paul Sabatier, 31062 Toulouse Cedex (France)

    2000-03-14

    Mechanisms of two-electron excitation of the (2s{sup 2}){sup 1} S, (2p{sup 2} ){sup 1} D and (2s2p){sup 1} P autoionizing states of helium are studied both experimentally and theoretically. It is shown that an explicit introduction of a kinematic factor, with a process-specific phase leads to a productive parametrization of experimental cross sections of ionization, allowing one to extract cross sections of excitation of autoionizing states. Using a new fitting procedure together with the proposed parametrization made it possible to obtain the excitation cross sections and magnetic sublevel population from electron spectra as well as, for the first time, to resolve the contribution of resonance and interference components to resonance profiles. Interference with direct ionization is shown to contribute significantly into resonance formation even for backward ejection angles. We demonstrate theoretically that the excitation cross sections thus extracted from experimental electron spectra hold information about the interaction of autoionizing states with an adjacent continuum. (author)

  20. Bound state and localization of excitation in many-body open systems

    Science.gov (United States)

    Cui, H. T.; Shen, H. Z.; Hou, S. C.; Yi, X. X.

    2018-04-01

    We study the exact bound state and time evolution for single excitations in one-dimensional X X Z spin chains within a non-Markovian reservoir. For the bound state, a common feature is the localization of single excitations, which means the spontaneous emission of excitations into the reservoir is prohibited. Exceptionally, the pseudo-bound state can be found, for which the single excitation has a finite probability of emission into the reservoir. In addition, a critical energy scale for bound states is also identified, below which only one bound state exists, and it is also the pseudo-bound state. The effect of quasirandom disorder in the spin chain is also discussed; such disorder induces the single excitation to locate at some spin sites. Furthermore, to display the effect of bound state and disorder on the preservation of quantum information, the time evolution of single excitations in spin chains is studied exactly. An interesting observation is that the excitation can stay at its initial location with high probability only when the bound state and disorder coexist. In contrast, when either one of them is absent, the information of the initial state can be erased completely or becomes mixed. This finding shows that the combination of bound state and disorder can provide an ideal mechanism for quantum memory.

  1. Vibrational spectroscopy of the electronically excited state. 4. Nanosecond and picosecond time-resolved resonance Raman spectroscopy of carotenoid excited states

    International Nuclear Information System (INIS)

    Dallinger, R.F.; Farquharson, S.; Woodruff, W.H.; Rodgers, M.A.J.

    1981-01-01

    Resonance Raman and electronic absorption spectra are reported for the S 0 and T 1 states of the carotenoids β-carotene, zeaxanthin, echinenone, canthaxanthin, dihydroxylycopene, astaxanthin, decapreno(C 50 )-β-carotene, β-apo-8'-carotenal, and ethyl β-apo-8'-carotenoate. The results reveal qualitatively similar ground-state spectra and similar frequency shifts in all observed resonance Raman modes between S 0 and T 1 , regardless of carotenoid structure. Examinations of the relationship of the putative C--C and C==C frequencies in S 0 and T 1 reveals anomalous shifts to lower frequency in the ''single-bond'' mode upon electronic excitation. These shifts may be due to molecular distortions in the excited state which force changes in molecular motions comprising the observed modes. However, another possibility requiring no distortion is that the interaction (off-diagonal) force constants connecting the C--C and C==C modes change sign upon electronic excitation. This latter phenomenon may provide a unitary explanation for the ''anomalous'' frequency shifts in the C--C and C==C modes, both in the T 1 states of carotenoids and in the S 1 states of simpler polyenes, without postulating large, unpredicted structural changes upon excitation or general errors in existing vibrational or theoretical analyses. Resonance Raman and absorbance studies with 35-ps time resolution suggest that S 1 lifetime (of the 1 B/sub u/ and/or the 1 A/sub g/* states) of β-carotene in benzene is less than 1 ps

  2. Coulomb displacement energies in nuclei: a new approach

    International Nuclear Information System (INIS)

    Auerbach, N.; Tel Aviv Univ.; Bernard, V.; Nguyen, V.G.

    1978-04-01

    The neutron core polarization gives rise to an important correction to the direct Coulomb contribution when one calculates the Coulomb displacement energies. In the Hartree-Fock model it is shown that this correction is about 2% to 4.5% in medium and heavy nuclei. The core polarization as well as other higher order effects can be included by using a selfconsistent description of the analog state in a complete proton particle-neutron hole space. The Coulomb displacement energies in 48 Ca, 88 Sr and 208 Pb have been calculated using Skyrme interactions SIII and SIV. A good agreement with experiment is obtained

  3. Inelastic scattering of 9Li and excitation mechanism of its first excited state

    International Nuclear Information System (INIS)

    Al Falou, H.; Kanungo, R.; Andreoiu, C.; Cross, D.S.; Davids, B.; Djongolov, M.; Gallant, A.T.; Galinski, N.; Howell, D.; Kshetri, R.; Niamir, D.; Orce, J.N.; Shotter, A.C.; Sjue, S.; Tanihata, I.; Thompson, I.J.; Triambak, S.; Uchida, M.; Walden, P.; Wiringa, R.B.

    2013-01-01

    The first measurement of inelastic scattering of 9 Li from deuterons at the ISAC facility is reported. The measured angular distribution for the first excited state confirms the nature of excitation to be an E2 transition. The quadrupole deformation parameter is extracted from an analysis of the angular distribution

  4. Enhanced Bulk-Edge Coulomb Coupling in Fractional Fabry-Perot Interferometers.

    Science.gov (United States)

    von Keyserlingk, C W; Simon, S H; Rosenow, Bernd

    2015-09-18

    Recent experiments use Fabry-Perot (FP) interferometry to claim that the ν=5/2 quantum Hall state exhibits non-Abelian topological order. We note that the experiments appear inconsistent with a model neglecting bulk-edge Coulomb coupling and Majorana tunneling, so we reexamine the theory of FP devices. Even a moderate Coulomb coupling may strongly affect some fractional plateaus, but very weakly affect others, allowing us to model the data over a wide range of plateaus. While experiments are consistent with the ν=5/2 state harboring Moore-Read topological order, they may have measured Coulomb effects rather than an "even-odd effect" due to non-Abelian braiding.

  5. Direct conversion of graphite into diamond through electronic excited states

    CERN Document Server

    Nakayama, H

    2003-01-01

    An ab initio total energy calculation has been performed for electronic excited states in diamond and rhombohedral graphite by the full-potential linearized augmented plane wave method within the framework of the local density approximation (LDA). First, calculations for the core-excited state in diamond have been performed to show that the ab initio calculations based on the LDA describe the wavefunctions in the electronic excited states as well as in the ground state quite well. Fairly good coincidence with both experimental data and theoretical prediction has been obtained for the lattice relaxation of the core exciton state. The results of the core exciton state are compared with nitrogen-doped diamond. Next, the structural stability of rhombohedral graphite has been investigated to examine the possibility of the transition into the diamond structure through electronic excited states. While maintaining the rhombohedral symmetry, rhombohedral graphite can be spontaneously transformed to cubic diamond. Tota...

  6. Non-perturbative RPA-method implemented in the Coulomb gauge QCD Hamiltonian: From quarks and gluons to baryons and mesons

    Science.gov (United States)

    Yepez-Martinez, Tochtli; Civitarese, Osvaldo; Hess, Peter O.

    2018-02-01

    Starting from an algebraic model based on the QCD-Hamiltonian and previously applied to study meson states, we have developed an extension of it in order to explore the structure of baryon states. In developing our approach we have adapted concepts taken from group theory and non-perturbative many-body methods to describe states built from effective quarks and anti-quarks degrees of freedom. As a Hamiltonian we have used the QCD Hamiltonian written in the Coulomb Gauge, and expressed it in terms of effective quark-antiquark, di-quarks and di-antiquark excitations. To gain some insights about the relevant interactions of quarks in hadronic states, the Hamiltonian was approximately diagonalized by mapping quark-antiquark pairs and di-quarks (di-antiquarks) onto phonon states. In dealing with the structure of the vacuum of the theory, color-scalar and color-vector states are introduced to account for ground-state correlations. While the use of a purely color-scalar ground state is an obvious choice, so that colorless hadrons contain at least three quarks, the presence of coupled color-vector pairs in the ground state allows for colorless excitations resulting from the action of color objects upon it.

  7. Self-Consistent Optimization of Excited States within Density-Functional Tight-Binding.

    Science.gov (United States)

    Kowalczyk, Tim; Le, Khoa; Irle, Stephan

    2016-01-12

    We present an implementation of energies and gradients for the ΔDFTB method, an analogue of Δ-self-consistent-field density functional theory (ΔSCF) within density-functional tight-binding, for the lowest singlet excited state of closed-shell molecules. Benchmarks of ΔDFTB excitation energies, optimized geometries, Stokes shifts, and vibrational frequencies reveal that ΔDFTB provides a qualitatively correct description of changes in molecular geometries and vibrational frequencies due to excited-state relaxation. The accuracy of ΔDFTB Stokes shifts is comparable to that of ΔSCF-DFT, and ΔDFTB performs similarly to ΔSCF with the PBE functional for vertical excitation energies of larger chromophores where the need for efficient excited-state methods is most urgent. We provide some justification for the use of an excited-state reference density in the DFTB expansion of the electronic energy and demonstrate that ΔDFTB preserves many of the properties of its parent ΔSCF approach. This implementation fills an important gap in the extended framework of DFTB, where access to excited states has been limited to the time-dependent linear-response approach, and affords access to rapid exploration of a valuable class of excited-state potential energy surfaces.

  8. Systematics in Rydberg state excitations for ion-atom collisions

    International Nuclear Information System (INIS)

    Andresen, B.; Jensen, K.; Petersen, N.B.; Veje, E.

    1976-01-01

    Rydberg state excitations in the Ne + , Mg + -He collisions have been studied in the projectile energy range 10-75 keV by means of optical spectrometry in a search for systematic trends. The relative excitation cross sections for levels of a Rydberg term series are found to follow a general (nsup(x))sup(P) behaviour with P < approximately -3 varying with collision energy and particles, regardless of whether the excited state population results from direct excitation, single electron transfer, or double electron transfer. At higher collision energies P is approximately -3 as predicted by theory. Polarization of the emitted line radiation indicates that there is no general rule for the relative excitation of the different magnetic substates of the same level. A statistical distribution of excitation is found for levels within the same term when the fine structure splitting is small. (Auth.)

  9. Contribution to the heavy-ion optical potential from coupling to vibrational states

    Energy Technology Data Exchange (ETDEWEB)

    Donangelo, R; Canto, L F; Hussein, M S

    1978-11-01

    The component of the optical potential in the elastic channel due to the coupling to vibrational states in Coulomb excitation is derived using a previously developed semiclassical method. Several numerical examples are worked out.

  10. Evaluation of the Coulomb logarithm using cutoff and screened Coulomb interaction potentials

    International Nuclear Information System (INIS)

    Ordonez, C.A.; Molina, M.I.

    1994-01-01

    The Coulomb logarithm is a fundamental plasma parameter which is commonly derived within the framework of the binary collision approximation. The conventional formula for the Coulomb logarithm, λ=ln Λ, takes into account a pure Coulomb interaction potential for binary collisions and is not accurate at small values (λ D in place of λ D (the Debye length) in the conventional formula for the Coulomb logarithm

  11. σ-SCF: A direct energy-targeting method to mean-field excited states.

    Science.gov (United States)

    Ye, Hong-Zhou; Welborn, Matthew; Ricke, Nathan D; Van Voorhis, Troy

    2017-12-07

    The mean-field solutions of electronic excited states are much less accessible than ground state (e.g., Hartree-Fock) solutions. Energy-based optimization methods for excited states, like Δ-SCF (self-consistent field), tend to fall into the lowest solution consistent with a given symmetry-a problem known as "variational collapse." In this work, we combine the ideas of direct energy-targeting and variance-based optimization in order to describe excited states at the mean-field level. The resulting method, σ-SCF, has several advantages. First, it allows one to target any desired excited state by specifying a single parameter: a guess of the energy of that state. It can therefore, in principle, find all excited states. Second, it avoids variational collapse by using a variance-based, unconstrained local minimization. As a consequence, all states-ground or excited-are treated on an equal footing. Third, it provides an alternate approach to locate Δ-SCF solutions that are otherwise hardly accessible by the usual non-aufbau configuration initial guess. We present results for this new method for small atoms (He, Be) and molecules (H 2 , HF). We find that σ-SCF is very effective at locating excited states, including individual, high energy excitations within a dense manifold of excited states. Like all single determinant methods, σ-SCF shows prominent spin-symmetry breaking for open shell states and our results suggest that this method could be further improved with spin projection.

  12. Core polarization and the Coulomb energy difference of mirror nuclei

    International Nuclear Information System (INIS)

    Barroso, A.

    1977-01-01

    The effect of the core polarization on the Coulomb displacement energies of mirror nuclei with a LS doubly closed shell plus or minus one nucleon is studied. Using the Kallio-Kolltveit interaction it is found that the first-order configuration mixing including 2p-2h core excitations is too small and sometimes of the wrong sign to explain the Nolen-Schiffer anomaly. (Auth.)

  13. Excited state conformational dynamics in carotenoids: dark intermediates and excitation energy transfer.

    Science.gov (United States)

    Beck, Warren F; Bishop, Michael M; Roscioli, Jerome D; Ghosh, Soumen; Frank, Harry A

    2015-04-15

    A consideration of the excited state potential energy surfaces of carotenoids develops a new hypothesis for the nature of the conformational motions that follow optical preparation of the S2 (1(1)Bu(+)) state. After an initial displacement from the Franck-Condon geometry along bond length alternation coordinates, it is suggested that carotenoids pass over a transition-state barrier leading to twisted conformations. This hypothesis leads to assignments for several dark intermediate states encountered in femtosecond spectroscopic studies. The Sx state is assigned to the structure reached upon the onset of torsional motions near the transition state barrier that divides planar and twisted structures on the S2 state potential energy surface. The X state, detected recently in two-dimensional electronic spectra, corresponds to a twisted structure well past the barrier and approaching the S2 state torsional minimum. Lastly, the S(∗) state is assigned to a low lying S1 state structure with intramolecular charge transfer character (ICT) and a pyramidal conformation. It follows that the bent and twisted structures of carotenoids that are found in photosynthetic light-harvesting proteins yield excited-state structures that favor the development of an ICT character and optimized energy transfer yields to (bacterio)chlorophyll acceptors. Copyright © 2015 Elsevier Inc. All rights reserved.

  14. On excited states in real-time AdS/CFT

    Energy Technology Data Exchange (ETDEWEB)

    Botta-Cantcheff, Marcelo; Martínez, Pedro J.; Silva, Guillermo A. [Instituto de Física de La Plata - CONICET & Departamento de Física - UNLP,C.C. 67, 1900 La Plata (Argentina)

    2016-02-25

    The Skenderis-van Rees prescription, which allows the calculation of time-ordered correlation functions of local operators in CFT’s using holographic methods is studied and applied for excited states. Calculation of correlators and matrix elements of local CFT operators between generic in/out states are carried out in global Lorentzian AdS. We find the precise form of such states, obtain an holographic formula to compute the inner product between them, and using the consistency with other known prescriptions, we argue that the in/out excited states built according to the Skenderis-Van Rees prescription correspond to coherent states in the (large-N) AdS-Hilbert space. This is confirmed by explicit holographic computations. The outcome of this study has remarkable implications on generalizing the Hartle-Hawking construction for wave functionals of excited states in AdS quantum gravity.

  15. From fusion hierarchy to excited state TBA

    International Nuclear Information System (INIS)

    Juettner, G.; Kluemper, A.

    1998-01-01

    Functional relations among the fusion hierarchy of quantum transfer matrices give a novel derivation of the TBA equations, namely without string hypothesis. This is demonstrated for two important models of 1D highly correlated electron systems, the supersymmetric t-J model and the supersymmetric extended Hubbard model. As a consequence, ''the excited state TBA'' equations, which characterize correlation lengths, are explicitly derived for the t-J model. To the authors' knowledge, this is the first explicit derivation of excited state TBA equations for 1D lattice electron systems. (orig.)

  16. Detection of a π-μ coulomb bound states

    International Nuclear Information System (INIS)

    Coombes, R.; Flexer, R.; Hall, A.

    1977-01-01

    The detection of hydrogen-like atoms is reported consisting of a negative (or positive) pion and a positive (or negative) muon in a coulomb bound state. These π-μ atoms are formed when the PI and μ from the decay have sufficiently small relative momentum to bind. Only the evidence related to the detection of these atoms is discussed. The Ksub(L)sup(0) particles which give rise to ''atomic beam'' are produced by 30 GeV proton beam striking a 10 cm beryllium target. From analysis of data 33 events are chosen. For each of these events the parameter α = Psub(π)-Psub(μ)/Psub(π)+Psub(μ) is plotted, where PPI is the pion momentum, and Pμ is the muon momentum. A study of this parameter through an examination of e + e - pairs indicates that the acceptance of apparatus is flat within 30%. The data shows a clear peak at the predicted point containing a total of 21 events with an estimated background of 3 events. The width of the peak is consistent with that expected from measurement errors

  17. Excitation of the (2p2)1D and (2s2p)1P autoionizing states of helium by 200 eV electron impact

    International Nuclear Information System (INIS)

    Godunov, A.L.; McGuire, J.H.; Schipakov, V.S.; Crowe, A.

    2002-01-01

    We report full second Born calculations with inclusion of post-collision interactions for excitation of the (2p 2 ) 1 D and (2s2p) 1 P autoionizing states of helium by 200 eV electron impact. The calculations are compared to (e, 2e) measurements of McDonald and Crowe (McDonald D G and Crowe A 1993 J. Phys. B: At. Mol. Opt. Phys. 26 2887-97) and Lower and Weigold (Lower J and Weigold E 1990 J. Phys. B: At. Mol. Opt. Phys. 23 2819-45). It is shown that post-collision interactions or Coulomb interactions in the final state between the scattered particle, the ejected electron and the recoil ion have a strong influence on both the direct ionization and resonance profiles around the binary lobe. The second-order terms in the amplitude of double electron excitation also play an observable role under these kinematic conditions. Reasonable agreement is found between the full-scale calculations and the experimental data. (author). Letter-to-the-editor

  18. Method of producing excited states of atomic nuclei

    International Nuclear Information System (INIS)

    Morita, M.; Morita, R.

    1976-01-01

    A method is claimed of producing excited states of atomic nuclei which comprises bombarding atoms with x rays or electrons, characterized in that (1) in the atoms selected to be produced in the excited state of their nuclei, (a) the difference between the nuclear excitation energy and the difference between the binding energies of adequately selected two electron orbits is small enough to introduce the nuclear excitation by electron transition, and (b) the system of the nucleus and the electrons in the case of ionizing an orbital electron in said atoms should satisfy the spin and parity conservation laws; and (2) the energy of the bombarding x rays or electrons should be larger than the binding energy of one of the said two electron orbits which is located at shorter distance from the atomic nucleus. According to the present invention, atomic nuclei can be excited in a relatively simple manner without requiring the use of large scale apparatus, equipment and production facilities, e.g., factories. It is also possible to produce radioactive substances or separate a particular isotope with an extremely high purity from a mixture of isotopes by utilizing nuclear excitation

  19. Electron impact excitation of the lowest doublet and quartet core-excited autoionizing states in Rb atoms

    International Nuclear Information System (INIS)

    Borovik, A; Roman, V; Zatsarinny, O; Bartschat, K

    2013-01-01

    Electron impact excitation of the (4p 5 5s 2 ) 2 P 3/2,1/2 and (4p 5 4d5s) 4 P 1/2,3/2,5/2 autoionizing states in rubidium atoms was studied experimentally by measuring the ejected-electron excitation functions and theoretically by employing a fully relativistic Dirac B-spline R-matrix (close-coupling) model. The experimental data were collected in an impact energy range from the respective excitation thresholds up to 50 eV with an incident electron energy resolution of 0.2 eV and an observation angle of 54.7°. Absolute values of the excitation cross sections were obtained by normalizing to the theoretical predictions. The observed near-threshold resonance structures were also analysed by comparison with theory. For the 2 P 3/2,1/2 doublet states, a detailed analysis of the R-matrix results reveals that the most intense resonances are related to odd-parity negative-ion states with dominant configurations 4p 5 5s5p 2 and 4p 5 4d5s6s. The measured excitation functions for the 2 P 1/2 and 4 P J states indicate a noticeable cascade population due to the radiative decay from high-lying autoionizing states. A comparative analysis with similar data for other alkali atoms is also presented.

  20. Coulomb matrix elements in multi-orbital Hubbard models.

    Science.gov (United States)

    Bünemann, Jörg; Gebhard, Florian

    2017-04-26

    Coulomb matrix elements are needed in all studies in solid-state theory that are based on Hubbard-type multi-orbital models. Due to symmetries, the matrix elements are not independent. We determine a set of independent Coulomb parameters for a d-shell and an f-shell and all point groups with up to 16 elements (O h , O, T d , T h , D 6h , and D 4h ). Furthermore, we express all other matrix elements as a function of the independent Coulomb parameters. Apart from the solution of the general point-group problem we investigate in detail the spherical approximation and first-order corrections to the spherical approximation.

  1. Controlling excited-state contamination in nucleon matrix elements

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Boram; Gupta, Rajan; Bhattacharya, Tanmoy; Engelhardt, Michael; Green, Jeremy; Joó, Bálint; Lin, Huey-Wen; Negele, John; Orginos, Kostas; Pochinsky, Andrew; Richards, David; Syritsyn, Sergey; Winter, Frank

    2016-06-01

    We present a detailed analysis of methods to reduce statistical errors and excited-state contamination in the calculation of matrix elements of quark bilinear operators in nucleon states. All the calculations were done on a 2+1 flavor ensemble with lattices of size $32^3 \\times 64$ generated using the rational hybrid Monte Carlo algorithm at $a=0.081$~fm and with $M_\\pi=312$~MeV. The statistical precision of the data is improved using the all-mode-averaging method. We compare two methods for reducing excited-state contamination: a variational analysis and a two-state fit to data at multiple values of the source-sink separation $t_{\\rm sep}$. We show that both methods can be tuned to significantly reduce excited-state contamination and discuss their relative advantages and cost-effectiveness. A detailed analysis of the size of source smearing used in the calculation of quark propagators and the range of values of $t_{\\rm sep}$ needed to demonstrate convergence of the isovector charges of the nucleon to the $t_{\\rm sep} \\to \\infty $ estimates is presented.

  2. A comparison of Coulomb and pseudo-Coulomb friction implementations: Application to the table contact phase of gymnastics vaulting.

    Science.gov (United States)

    Jackson, M I; Hiley, M J; Yeadon, M R

    2011-10-13

    In the table contact phase of gymnastics vaulting both dynamic and static friction act. The purpose of this study was to develop a method of simulating Coulomb friction that incorporated both dynamic and static phases and to compare the results with those obtained using a pseudo-Coulomb implementation of friction when applied to the table contact phase of gymnastics vaulting. Kinematic data were obtained from an elite level gymnast performing handspring straight somersault vaults using a Vicon optoelectronic motion capture system. An angle-driven computer model of vaulting that simulated the interaction between a seven segment gymnast and a single segment vaulting table during the table contact phase of the vault was developed. Both dynamic and static friction were incorporated within the model by switching between two implementations of the tangential frictional force. Two vaulting trials were used to determine the model parameters using a genetic algorithm to match simulations to recorded performances. A third independent trial was used to evaluate the model and close agreement was found between the simulation and the recorded performance with an overall difference of 13.5%. The two-state simulation model was found to be capable of replicating performance at take-off and also of replicating key contact phase features such as the normal and tangential motion of the hands. The results of the two-state model were compared to those using a pseudo-Coulomb friction implementation within the simulation model. The two-state model achieved similar overall results to those of the pseudo-Coulomb model but obtained solutions more rapidly. Copyright © 2011 Elsevier Ltd. All rights reserved.

  3. Nonadiabatic excited-state molecular dynamics: On-the-fly limiting of essential excited states

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, Tammie [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Naumov, Artem [Skolkovo Institute of Science and Technology, Moscow 143026 (Russian Federation); Fernandez-Alberti, Sebastian [Universidad Nacional de Quilmes, Roque Saenz Pea 352, B1876BXD Bernal (Argentina); Tretiak, Sergei, E-mail: serg@lanl.gov [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2016-12-20

    The simulation of nonadiabatic dynamics in extended molecular systems involving hundreds of atoms and large densities of states is particularly challenging. Nonadiabatic coupling terms (NACTs) represent a significant numerical bottleneck in surface hopping approaches. Rather than using unreliable NACT cutting schemes, here we develop “on-the-fly” state limiting methods to eliminate states that are no longer essential for the non-radiative relaxation dynamics as a trajectory proceeds. We propose a state number criteria and an energy-based state limit. The latter is more physically relevant by requiring a user-imposed energy threshold. For this purpose, we introduce a local kinetic energy gauge by summing contributions from atoms within the spatial localization of the electronic wavefunction to define the energy available for upward hops. The proposed state limiting schemes are implemented within the nonadiabatic excited-state molecular dynamics framework to simulate photoinduced relaxation in poly-phenylene vinylene (PPV) and branched poly-phenylene ethynylene (PPE) oligomers for benchmark evaluation.

  4. Excited state populations and charge-exchange of fast ions in solids

    International Nuclear Information System (INIS)

    Miller, P.D.; Sofield, C.J.; Woods, C.J.

    1984-01-01

    Excited state populations and charge state fractions of 445 MeV Cl ions have been measured for a range of thicknesses of solid C targets. Cross sections for electron capture, loss, excitation and excited state quenching have been determined and these data are found to predict a quantitative difference between equilibrium charge state distributions from gases and solids for a special case of the Bohr-Lindhard density effect model. 8 references, 1 figure, 1 table

  5. Coulomb displacement energy of the f sub(7/2) state of the 48Ca

    International Nuclear Information System (INIS)

    Sato, Hiroshi.

    1979-11-01

    The Coulomb displacement energy of the T = 4, J = 0 state of the 48 Ca is analyzed. Modifying a previous method of the calculation of the core polarization correction, it is found that the charge symmetry breaking force, which is introduced previously so as to help explain the Nolen-Schiffer anomaly of the T = 1/2 system, is also needed in this system, while there still exists an ambituity in the type of the force. (author)

  6. Localization of Dirac-like excitations in graphene in the presence of smooth inhomogeneous magnetic fields.

    Science.gov (United States)

    Roy, Pratim; Ghosh, Tarun Kanti; Bhattacharya, Kaushik

    2012-02-08

    The present paper discusses magnetic confinement of the Dirac excitations in graphene in the presence of inhomogeneous magnetic fields. In the first case a magnetic field directed along the z axis whose magnitude is proportional to 1/r is chosen. In the next case we choose a more realistic magnetic field which does not blow up at the origin and gradually fades away from the origin. The magnetic fields chosen do not have any finite/infinite discontinuity for finite values of the radial coordinate. The novelty of the two magnetic fields is related to the equations which are used to find the excited spectra of the excitations. It turns out that the bound state solutions of the two-dimensional hydrogen atom problem are related to the spectra of graphene excitations in the presence of the 1/r (inverse-radial) magnetic field. For the other magnetic field profile one can use the knowledge of the bound state spectrum of a two-dimensional cutoff Coulomb potential to dictate the excitation spectra of graphene. The spectrum of the graphene excitations in the presence of the inverse-radial magnetic field can be exactly solved while the other case cannot be. In the later case we give the localized solutions of the zero-energy states in graphene.

  7. Excited states of open strings from N=4 SYM

    International Nuclear Information System (INIS)

    Dzienkowski, Eric

    2015-01-01

    We continue the analysis of building open strings stretched between giant gravitons from N=4 SYM by going to second order in perturbation theory using the three-loop dilatation generator from the field theory. In the process we build a Fock-like space of states using Cuntz oscillators which can be used to access the excited open string states. We find a remarkable cancellation among the excited states that shows the ground state energy is consistent with a fully relativistic dispersion relation.

  8. Coulomb drag in coherent mesoscopic systems

    DEFF Research Database (Denmark)

    Mortensen, Asger; Flensberg, Karsten; Jauho, Antti-Pekka

    2001-01-01

    We present a theory for Coulomb drag between two mesoscopic systems. Our formalism expresses the drag in terms of scattering matrices and wave functions, and its range of validity covers both ballistic and disordered systems. The consequences can be worked out either by analytic means, such as th......We present a theory for Coulomb drag between two mesoscopic systems. Our formalism expresses the drag in terms of scattering matrices and wave functions, and its range of validity covers both ballistic and disordered systems. The consequences can be worked out either by analytic means......, such as the random matrix theory, or by numerical simulations. We show that Coulomb drag is sensitive to localized states. which usual transport measurements do not probe. For chaotic 2D systems we find a vanishing average drag, with a nonzero variance. Disordered 1D wires show a finite drag, with a large variance...

  9. σ-SCF: A direct energy-targeting method to mean-field excited states

    Science.gov (United States)

    Ye, Hong-Zhou; Welborn, Matthew; Ricke, Nathan D.; Van Voorhis, Troy

    2017-12-01

    The mean-field solutions of electronic excited states are much less accessible than ground state (e.g., Hartree-Fock) solutions. Energy-based optimization methods for excited states, like Δ-SCF (self-consistent field), tend to fall into the lowest solution consistent with a given symmetry—a problem known as "variational collapse." In this work, we combine the ideas of direct energy-targeting and variance-based optimization in order to describe excited states at the mean-field level. The resulting method, σ-SCF, has several advantages. First, it allows one to target any desired excited state by specifying a single parameter: a guess of the energy of that state. It can therefore, in principle, find all excited states. Second, it avoids variational collapse by using a variance-based, unconstrained local minimization. As a consequence, all states—ground or excited—are treated on an equal footing. Third, it provides an alternate approach to locate Δ-SCF solutions that are otherwise hardly accessible by the usual non-aufbau configuration initial guess. We present results for this new method for small atoms (He, Be) and molecules (H2, HF). We find that σ-SCF is very effective at locating excited states, including individual, high energy excitations within a dense manifold of excited states. Like all single determinant methods, σ-SCF shows prominent spin-symmetry breaking for open shell states and our results suggest that this method could be further improved with spin projection.

  10. Application of Stochastic variational method with correlated Ground States to coulombic systems

    Energy Technology Data Exchange (ETDEWEB)

    Usukura, Junko; Suzuki, Yasuyuki [Niigata Univ. (Japan); Varga, K.

    1998-07-01

    Positronium molecule, Ps{sub 2} has not been found experimentally yet, and it has been believed theoretically that Ps{sub 2} has only one bound state with L = 0. We predicted the existence of new bound state of Ps{sub 2}, which is the excited state with L = 1 and comes from Pauli principle, by Stochastic variational method. There are two decay mode with respect to Ps{sub 2}(P); one is pair annihilation and another is electric dipole (E1) transition to the ground state. While it is difficult to tell {gamma}-ray caused by annihilation of Ps{sub 2} from that of Ps since both of them have same energy, Energy (4.94 eV) of the photon emitted in E1 transition is specific enough to distinguish from other spectra. Then the excited state is one of clues to observe Ps{sub 2}. (author)

  11. Coulomb Dissociation as a Tool of Nuclear Astrophysics

    International Nuclear Information System (INIS)

    Utsunomiya, H.

    2000-01-01

    My talk will begin with an introduction of the Coulomb dissociation method, proceed to discussions on Coulomb breakup of 7 Li with respect to the big-bang nucleosynthesis and end with the revision of astrophysical S-factors. The methodology based on the virtual photon source will be introduced in view of experimental techniques. The discussion will include the quantum tunnelling effect in non-resonant breakup, the lifetime of continuum states, and Coulomb distortion of relevant cross sections. Roles of multi-step processes and different multipolarities will also be discussed on the basis of solving a time-dependent Schroedinger equation. My talk will present quantitative results. The theoretical framework of the Coulomb dissociation method and a broad scope of its applications are given by G. Baur. Applications to radioactive nuclei which have quickly become vogue are discussed in the related lecture of J. Kiener. (author)

  12. Inelastic scattering of {sup 9}Li and excitation mechanism of its first excited state

    Energy Technology Data Exchange (ETDEWEB)

    Al Falou, H. [Astronomy and Physics Department, Saint Mary' s University, Halifax, Nova Scotia B3H 3C3 (Canada); TRIUMF, Vancouver, British Columbia V6T 2A3 (Canada); Kanungo, R., E-mail: ritu@triumf.ca [Astronomy and Physics Department, Saint Mary' s University, Halifax, Nova Scotia B3H 3C3 (Canada); Andreoiu, C.; Cross, D.S. [Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6 (Canada); Davids, B.; Djongolov, M. [TRIUMF, Vancouver, British Columbia V6T 2A3 (Canada); Gallant, A.T. [TRIUMF, Vancouver, British Columbia V6T 2A3 (Canada); Department of Physics, University of British Columbia, British Columbia V6T 1Z4 (Canada); Galinski, N.; Howell, D. [TRIUMF, Vancouver, British Columbia V6T 2A3 (Canada); Department of Physics, Simon Fraser University, Burnaby, British Columbia V5A 1S6 (Canada); Kshetri, R.; Niamir, D. [TRIUMF, Vancouver, British Columbia V6T 2A3 (Canada); Orce, J.N. [TRIUMF, Vancouver, British Columbia V6T 2A3 (Canada); Department of Physics, University of the Western Cape, P/B X17, Bellville, ZA-7535 (South Africa); Shotter, A.C. [Department of Physics and Astronomy, University of Edinburgh, Edinburgh (United Kingdom); Sjue, S. [TRIUMF, Vancouver, British Columbia V6T 2A3 (Canada); Tanihata, I. [Research Center for Nuclear Physics, Osaka University, Mihogaoka, Ibaraki, Osaka 567 0047 (Japan); Thompson, I.J. [Lawrence Livermore National Laboratory, Livermore, CA 94551 (United States); Triambak, S. [TRIUMF, Vancouver, British Columbia V6T 2A3 (Canada); Uchida, M. [Astronomy and Physics Department, Saint Mary' s University, Halifax, Nova Scotia B3H 3C3 (Canada); Walden, P. [TRIUMF, Vancouver, British Columbia V6T 2A3 (Canada); Wiringa, R.B. [Physics Division, Argonne National Laboratory, Argonne, IL 60439 (United States)

    2013-04-25

    The first measurement of inelastic scattering of {sup 9}Li from deuterons at the ISAC facility is reported. The measured angular distribution for the first excited state confirms the nature of excitation to be an E2 transition. The quadrupole deformation parameter is extracted from an analysis of the angular distribution.

  13. Search for the two-photon decay of the 2+ first excited states in 18O and 28Si

    International Nuclear Information System (INIS)

    Music, M.

    1986-01-01

    The present work describes an attempt to measure the probability for the two-photon transition between two adjacent nuclear states in the presence of an allowed, strongly predominant one-photon decay, using the Heidelberg-Darmstadt Crystal Ball Spectrometer. The branching ratios of the two-photon decay of the first excited, 2 + levels of 18 O and 28 Si relative to the one-photon, E2 transitions to the 0 + ground states were determined to be: Wγγ/Wγ = (0.7±2.4) x 10 -6 for the 2 + >0 + transition in 18 O and Wγγ/Wγ = (1.6±1.8) x 10 -6 for the 2 + >0 + transition in 28 Si. Since both results are consistent with zero, it is possible to express them as the upper limits for the two-photon decay (3 δ) of 7.9 x 10 -6 of 18 O and 6.9 x 10 -6 of 28 Si 2 + levels. These values are by far the smallest ones reported to be observed in a two-photon decay of a nuclear state. For 18 O, the result disproves theoretical estimates of the corresponding two-photon E1F1 matrix element was well as experimental values deduced from multiple-Coulomb-excitation measurements. The main experimental difficulties were caused by the gamma rays from one-photon transitions and were found to be connected with cross-talk events due to Bremsstrahlung of Compton electrons and not - as generally believed - positron annihilation in flight. (orig.)

  14. The Sommerfeld enhancement for dark matter with an excited state

    International Nuclear Information System (INIS)

    Slatyer, Tracy R.

    2010-01-01

    We present an analysis of the Sommerfeld enhancement to dark matter annihilation in the presence of an excited state, where the interaction inducing the enhancement is purely off-diagonal, such as in models of exciting or inelastic dark matter. We derive a simple and accurate semi-analytic approximation for the s-wave enhancement, which is valid provided the mass splitting between the ground and excited states is not too large, and discuss the cutoff of the enhancement for large mass splittings. We reproduce previously derived results in the appropriate limits, and demonstrate excellent agreement with numerical calculations of the enhancement. We show that the presence of an excited state leads to generically larger values of the Sommerfeld enhancement, larger resonances, and shifting of the resonances to lower mediator masses. Furthermore, in the presence of a mass splitting the enhancement is no longer a monotonic function of velocity: the enhancement where the kinetic energy is close to that required to excite the higher state can be up to twice as large as the enhancement at zero velocity

  15. The excited states of 79Kr

    International Nuclear Information System (INIS)

    Liptak, J.; Kristiak, J.; Kristiakova, K.

    1977-01-01

    The β + -decay of 79 Rb has been studied with Ge(Li) detectors in single and coincidence modes. The half-life of the 147.06 keV level in 79 Kr has been determined to be (78+-6) ns. The relative electron intensities of seventeen transitions have been measured with a magnetic Si(Li) spectrometer. The internal conversion coefficients have been determined. The transition multipolarities have been deduced. The spin-parity assignments have been made for excited states of 79 Kr and a β-decaying sta 79 Rb(5/2 + ). The structure of excited states in 79 Kr is discussed in the framework of the Alaga and Coriolis coupling models. It is shown that the properties of some levels in 79 Kr can be explained by the existence of relatively pure rotational bands

  16. Effects of screened Coulomb (Yukawa) and exponential-cosine-screened Coulomb potentials on photoionization of H and He+

    International Nuclear Information System (INIS)

    Lin, C.Y.; Ho, Y.K.

    2010-01-01

    The screening effects due to the exponential-cosine-screened Coulomb and screened Coulomb (Yukawa) potentials on photoionization processes are explored within the framework of complex coordinate rotation method. The energy levels of H and He + in both screened potentials shifted with various Debye screening lengths are presented. The photoionization cross sections illustrate the considerable screening effects on photoionization processes in low energy region. The shape resonances can be found near ionization thresholds for certain of Debye screening lengths. The relations between the appearance of resonances and the existence of quasi-bound states under shielding conditions are discussed. (authors)

  17. Excited state electron affinity calculations for aluminum

    Science.gov (United States)

    Hussein, Adnan Yousif

    2017-08-01

    Excited states of negative aluminum ion are reviewed, and calculations of electron affinities of the states (3s^23p^2)^1D and (3s3p^3){^5}{S}° relative to the (3s^23p)^2P° and (3s3p^2)^4P respectively of the neutral aluminum atom are reported in the framework of nonrelativistic configuration interaction (CI) method. A priori selected CI (SCI) with truncation energy error (Bunge in J Chem Phys 125:014107, 2006) and CI by parts (Bunge and Carbó-Dorca in J Chem Phys 125:014108, 2006) are used to approximate the valence nonrelativistic energy. Systematic studies of convergence of electron affinity with respect to the CI excitation level are reported. The calculated value of the electron affinity for ^1D state is 78.675(3) meV. Detailed Calculations on the ^5S°c state reveals that is 1216.8166(3) meV below the ^4P state.

  18. Anyonic states in Chern-Simons theory

    International Nuclear Information System (INIS)

    Haller, K.; Lim-Lombridas, E.

    1994-01-01

    We discuss the canonical quantization of Chern-Simons theory in 2+1 dimensions, minimally coupled to a Dirac spinor field, first in the temporal gauge and then in the Coulomb gauge. In our temporal gauge formulation, Gauss's law and the gauge condition A 0 =0 are implemented by embedding the formulation in an appropriate physical subspace. We construct a Fock space of charged particle states that satisfy Gauss's law, and show that they obey fermion, not fractional statistics. The gauge-invariant spinor field that creates these charged states from the vacuum obeys the anticommutation rules that generally apply to spinor fields. The Hamiltonian, when described in the representation in which the charged fermions are the propagating particle excitations that obey Gauss's law, contains an interaction between charge and transverse current densities. We observe that the implementation of Gauss's law and the gauge condition does not require us to use fields with graded commutator algebras or particle excitations with fractional statistics. In our Coulomb gauge formulation, we implement Gauss's law and the gauge condition ∂ l A l =0 by the Dirac-Bergmann procedure. In this formulation, the constrained gauge fields become functionals of the spinor fields, and are not independent degrees of freedom. The formulation in the Coulomb gauge confirms the results we obtained in the temporal gauge: The ''Dirac-Bergmann'' anticommutation rule for the charged spinor fiels ψ and ψ degree that have both been constrained to obey Gauss's law is precisely identical to the canonical spinor anticommutation rule that generates standard fermion statistics. And we also show that the Hamiltonians for charged particle states in our temporal and Coulomb gauge formulations are identical, once Gauss's law has been implemented in both cases

  19. Nested variant of the method of moments of coupled cluster equations for vertical excitation energies and excited-state potential energy surfaces.

    Science.gov (United States)

    Kowalski, Karol

    2009-05-21

    In this article we discuss the problem of proper balancing of the noniterative corrections to the ground- and excited-state energies obtained with approximate coupled cluster (CC) and equation-of-motion CC (EOMCC) approaches. It is demonstrated that for a class of excited states dominated by single excitations and for states with medium doubly excited component, the newly introduced nested variant of the method of moments of CC equations provides mathematically rigorous way of balancing the ground- and excited-state correlation effects. The resulting noniterative methodology accounting for the effect of triples is tested using its parallel implementation on the systems, for which iterative CC/EOMCC calculations with full inclusion of triply excited configurations or their most important subset are numerically feasible.

  20. Doubly and triply excited states for different plasma sources

    International Nuclear Information System (INIS)

    More, R.M.; Safronova, U.I.

    2000-01-01

    Autoionizing rates of doubly excited states as nln'l' configurations with n=2-9 and n'=2-9 are calculated. Analytical expressions of decay amplitude for two-electron system are derived. Expressions for autoionizing rates with averaging over LS are obtained for many-electron systems. The n and l dependence of doubly excited states as nln'l' configurations are investigated. (author)

  1. Examination of excited state populations in sputtering using Multiphoton Resonance Ionization

    International Nuclear Information System (INIS)

    Kimock, F.M.; Baxter, J.P.; Pappas, D.L.; Kobrin, P.H.; Winograd, N.

    1984-01-01

    Multiphoton Resonance Ionization has been employed to study the populations of excited state atoms ejected from ion bombarded metal surfaces. Preliminary investigations have focused on three model systems: aluminum, indium and cobalt. In this paper the authors examine the effect of primary ion energy (2 to 12 keV Ar + ) on excited state yields for these three systems. The influence of the sample matrix on excited state populations of sputtered atoms is also discussed

  2. Coupled state analysis of electron excitations in asymmetric collision systems

    International Nuclear Information System (INIS)

    Mehler, G.; Reus, T. de; Mueller, U.; Reinhardt, J.; Mueller, B.; Greiner, W.; Soff, G.

    1985-01-01

    A coupled channel formalism is presented, using relativistic basis states of the target atom. Screening effects are incorporated by means of an effective potential of Hartree-Fock-Slater type. Relativistic wave packets are employed for the description of the continuum. The impact parameter dependence of the K-hole production in p-Ag collisions is calculated, including quadrupole contributions of the projectile Coulomb potential. The results are compared with experimental data. (orig.)

  3. On the Emergence of the Coulomb Forces in Quantum Electrodynamics

    Directory of Open Access Journals (Sweden)

    Jan Naudts

    2017-01-01

    Full Text Available A simple transformation of field variables eliminates Coulomb forces from the theory of quantum electrodynamics. This suggests that Coulomb forces may be an emergent phenomenon rather than being fundamental. This possibility is investigated in the context of reducible quantum electrodynamics. It is shown that states exist which bind free photon and free electron fields. The binding energy peaks in the long-wavelength limit. This makes it plausible that Coulomb forces result from the interaction of the electron/positron field with long-wavelength transversely polarized photons.

  4. Gyromagnetic ratios of excited states in 198Pt; measurements and interacting boson approximation model calculations

    Science.gov (United States)

    Stuchbery, A. E.; Ryan, C. G.; Bolotin, H. H.; Morrison, I.; Sie, S. H.

    1981-07-01

    The enhanced transient hyperfine field manifest at the nuclei of swiftly recoiling ions traversing magnetized ferromagnetic materials was utilized to measure the gyromagnetic ratios of the 2 +1, 2 +2 and 4 +1 states in 198Pt by the thin-foil technique. The states of interest were populated by Coulomb excitation using a beam of 220 MeV 58Ni ions. The results obtained were: g(2 +1) = 0.324 ± 0.026; g(2 +2) = 0.34 ± 0.06; g(4 +1) = 0.34 ± 0.06. In addition, these measurements served to discriminate between the otherwise essentially equally probable values previously reported for the E2/M1 ratio of the 2 +2 → 2 +1 transition in 198Pt. We also performed interacting boson approximation (IBA) model-based calculations in the O(6) limit symmetry, with and without inclusion of a small degree of symmetry breaking, and employed the M1 operator in both first- and second-order to obtain M1 selection rules and to calculate gyromagnetic ratios of levels. When O(6) symmetry is broken, there is a predicted departure from constancy of the g-factors which provides a good test of the nuclear wave function. Evaluative comparisons are made between these experimental and predicted g-factors.

  5. Analytical study of doubly excited ridge states

    International Nuclear Information System (INIS)

    Wong, H.Y.

    1988-01-01

    Two different non-separable problems are explored and analyzed. Non-perturbative methods need to be used to handle them, as the competing forces involved in these problems are equally strong and do not yield to a perturbative analysis. The first one is the study of doubly excited ridge states of atoms, in which two electrons are comparably excited. An analytical wavefunction for such states is introduced and is used to solve the two-electron Hamiltonian in the pair coordinates called hyperspherical coordinates variationally. The correlation between the electrons is built in analytically into the structure of the wavefunction. Sequences of ridge states out to very high excitation are computed and are organized as Rydberg series converging to the double ionization limit. Numerical results of such states in He and H - are compared with other theoretical calculations where available. The second problem is the analysis of the photodetachment of negative ions in an electric field via the frame transformation theory. The presence of the electron field requires a transformation from spherical to cylindrical symmetry for the outgoing photoelectron. This gives an oscillatory modulating factor as the effect of the electric field on cross-sections. All of this work is derived analytically in a general form applicable to the photodetachment of any negative ion. The expressions are applied to H - and S - for illustration

  6. Dinamical polarizability of highly excited hydrogen-like states

    International Nuclear Information System (INIS)

    Delone, N.B.; Krajnov, V.P.

    1982-01-01

    Analytic expressions are derived for the dynamic polarizability of highly excited hydrogen-like atomic states. It is shown that in the composite matrix element which determines the dynamic polarizability there is a strong compensation of the terms as a result of which the resulting magnitude of the dynamic polarizability is quasiclasically small compared to the individual terms of the composite matrix. It is concluded that the resonance behaviour of the dynamic polarizability of highly excited states differs significantly from the resonance behaviour of the polarizability for the ground and low-lying atomic states. The static limit and high-frequency limit of on electromagnetic field are considered

  7. Coulomb interactions in charged fluids.

    Science.gov (United States)

    Vernizzi, Graziano; Guerrero-García, Guillermo Iván; de la Cruz, Monica Olvera

    2011-07-01

    The use of Ewald summation schemes for calculating long-range Coulomb interactions, originally applied to ionic crystalline solids, is a very common practice in molecular simulations of charged fluids at present. Such a choice imposes an artificial periodicity which is generally absent in the liquid state. In this paper we propose a simple analytical O(N(2)) method which is based on Gauss's law for computing exactly the Coulomb interaction between charged particles in a simulation box, when it is averaged over all possible orientations of a surrounding infinite lattice. This method mitigates the periodicity typical of crystalline systems and it is suitable for numerical studies of ionic liquids, charged molecular fluids, and colloidal systems with Monte Carlo and molecular dynamics simulations.

  8. Excitation of non-normal parity states by inelastic proton scattering

    Energy Technology Data Exchange (ETDEWEB)

    Emery, G. T. [Indiana Univ. (USA). Cyclotron Facility; Ikegami, Hidetsugu; Muraoka, Mitsuo [eds.; Osaka Univ., Suita (Japan). Research Center for Nuclear Physics

    1980-01-01

    This is a review of the works done at the Indiana University Cyclotron Facility. The purposes of works are to find excitations that should have especially simple particle-hole structure in proton inelastic scattering, to use the data on these excitations to try to understand the mechanism and the effective interaction for the (p, p') reaction in this energy range, and to go on to study the nuclear structure involved in less simple excitation. As an example, the single-nucleon level diagram for the region of Si-28 is presented. A high spin state was made, and its spin-parity was 6/sup -/. It was tried to interpret the data in terms of a on-step distorted-wave impulse approximation. The optical model parameters derived from the extensive and precise elastic scattering results were used. The cross sections for the excitation of the 6/sup -/ states found in various reactions were not large. The T = 1 state is mainly excited by the direct tensor interaction, while the T = 0 state gets its strength mainly from the knock-on exchange contribution of both the tensor and spin-orbit interactions. Experiments on Pb-208 and Fe-54 are being performed.

  9. Examination of excited state populations in sputtering using multiphoton resonance ionization

    International Nuclear Information System (INIS)

    Kimock, F.M.; Baxter, J.P.; Pappas, D.L.; Kobrin, P.H.; Winograd, N.

    1984-01-01

    Multiphoton Resonance Ionization has been employed to study the populations of excited state atoms ejected from ion bombarded metal surfaces. Preliminary investigations have focused on three model systems: aluminum, indium and cobalt. In this paper we examine the effect of primary ion energy (2 to 12 keV Ar + ) on excited state yields for these three systems. The influence of the sample matrix on excited state populations of sputtered atoms is also discussed. 8 refs., 4 figs

  10. Excited-State Dynamics of Carotenoids Studied by Femtosecond Transient Absorption Spectroscopy

    International Nuclear Information System (INIS)

    Lee, Ingu; Pang, Yoonsoo; Lee, Sebok

    2014-01-01

    Carotenoids, natural antenna pigments in photosynthesis share a symmetric backbone of conjugated polyenes. Contrary to the symmetric and almost planar geometries of carotenoids, excited state structure and dynamics of carotenoids are exceedingly complex. In this paper, recent infrared and visible transient absorption measurements and excitation dependent dynamics of 8'-apo-β-caroten-8'-al and 7',7'-dicyano-7'-apo-β-carotene will be reviewed. The recent visible transient absorption measurements of 8'-apo-β-caroten-8'-al in polar and nonpolar solvents will also be introduced to emphasize the complex excited-state dynamics and unsolved problems in the S 2 and S 1 excited states

  11. Cathodoluminescence imaging and spectroscopy of excited states in InAs self-assembled quantum dots

    International Nuclear Information System (INIS)

    Khatsevich, S.; Rich, D.H.; Kim, Eui-Tae; Madhukar, A.

    2005-01-01

    We have examined state filling and thermal activation of carriers in buried InAs self-assembled quantum dots (SAQDs) with excitation-dependent cathodoluminescence (CL) imaging and spectroscopy. The InAs SAQDs were formed during molecular-beam epitaxial growth of InAs on undoped planar GaAs (001). The intensities of the ground- and excited-state transitions were analyzed as a function of temperature and excitation density to study the thermal activation and reemission of carriers. The thermal activation energies associated with the thermal quenching of the luminescence were measured for ground- and excited-state transitions of the SAQDs, as a function of excitation density. By comparing these activation energies with the ground- and excited-state transition energies, we have considered various processes that describe the reemission of carriers. Thermal quenching of the intensity of the QD ground- and first excited-state transitions at low excitations in the ∼230-300-K temperature range is attributed to dissociation of excitons from the QD states into the InAs wetting layer. At high excitations, much lower activation energies of the ground and excited states are obtained, suggesting that thermal reemission of single holes from QD states into the GaAs matrix is responsible for the observed temperature dependence of the QD luminescence in the ∼230-300-K temperature range. The dependence of the CL intensity of the ground-and first excited-state transition on excitation density was shown to be linear at all temperatures at low-excitation density. This result can be understood by considering that carriers escape and are recaptured as excitons or correlated electron-hole pairs. At sufficiently high excitations, state-filling and spatial smearing effects are observed together with a sublinear dependence of the CL intensity on excitation. Successive filling of the ground and excited states in adjacent groups of QDs that possess different size distributions is assumed to

  12. Photophysics of trioxatriangulenium ion. Electrophilic reactivity in the ground state and excited singlet state

    DEFF Research Database (Denmark)

    Reynisson, J.; Wilbrandt, R.; Brinck, V.

    2002-01-01

    . The physical and chemical properties of the excited singlet state of the trioxatriangulenium (TOTA(+)) carbenium ion are investigated by experimental and Computational means. The degeneracy of the lowest excited states is counteracted by Jahn-Teller-type distortion, which leads to vibronic broadening...... of the long wavelength absorption band. A strong fluorescence is observed at 520 nm (tau(n) = 14.6 ns, phi(n) = 0.12 in deaerated acetonitrile). The fluorescence is quenched by 10 aromatic electron donors predominantly via a dynamic charge transfer mechanism, but ground state complexation is shown...... triphenylenes is studied separately. Phosphorescence spectra, triplet lifetimes, and triplet-triplet absorption spectra are provided. In the discussion, TOTA(+) is compared to the unsubstituted xanthenium ion and its 9-phenyl derivative with respect to the excited state properties....

  13. Excitation and photon decay of giant multipole resonances

    International Nuclear Information System (INIS)

    Bertrand, F.E.; Beene, J.R.

    1990-01-01

    A brief review of the excitation of giant multipole resonances via Coulomb excitation is given which emphasizes the very large cross sections that can be realized through this reaction for both isoscalar and isovector resonances. Discussion and results where available, are provide for the measurement of the photon decay of one and two phonon giant resonances. It is pointed out throughout the presentation that the use of E1 photons as a ''tag'' provides a means to observe weakly excited resonances that cannot be observed in the singles spectra. 14 refs., 12 figs., 1 tab

  14. DILEPTON YIELD FROM THE DECAY OF EXCITED SI-28 STATES

    NARCIS (Netherlands)

    BACELAR, JC; BUDA, A; BALANDA, A; KRASZNAHORKAY, A; VANDERPLOEG, H; SUJKOWSKI, Z; VANDERWOUDE, A

    1994-01-01

    The first dilepton yield measurements from excited nuclear states obtained with a new Positron-Electron Pair Spectroscopic Instrument (PEPSI) are reported. Nuclear states in Si-28, with an initial excitation energy E* = 50 MeV, were populated via the isospin T = 0 reaction He-4 + Mg-24 and the

  15. Thermality and excited state Rényi entropy in two-dimensional CFT

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Feng-Li [Department of Physics, National Taiwan Normal University,Taipei 11677, Taiwan (China); Wang, Huajia [Department of Physics, University of Illinois,Urbana-Champaign, IL 61801 (United States); Zhang, Jia-ju [Dipartimento di Fisica, Università degli Studi di Milano-Bicocca,Piazza della Scienza 3, I-20126 Milano (Italy); Theoretical Physics Division, Institute of High Energy Physics, Chinese Academy of Sciences,19B Yuquan Rd, Beijing 100049 (China); Theoretical Physics Center for Science Facilities, Chinese Academy of Sciences,19B Yuquan Rd, Beijing 100049 (China)

    2016-11-21

    We evaluate one-interval Rényi entropy and entanglement entropy for the excited states of two-dimensional conformal field theory (CFT) on a cylinder, and examine their differences from the ones for the thermal state. We assume the interval to be short so that we can use operator product expansion (OPE) of twist operators to calculate Rényi entropy in terms of sum of one-point functions of OPE blocks. We find that the entanglement entropy for highly excited state and thermal state behave the same way after appropriate identification of the conformal weight of the state with the temperature. However, there exists no such universal identification for the Rényi entropy in the short-interval expansion. Therefore, the highly excited state does not look thermal when comparing its Rényi entropy to the thermal state one. As the Rényi entropy captures the higher moments of the reduced density matrix but the entanglement entropy only the average, our results imply that the emergence of thermality depends on how refined we look into the entanglement structure of the underlying pure excited state.

  16. Electronic excited states and relaxation dynamics in polymer heterojunction systems

    Science.gov (United States)

    Ramon, John Glenn Santos

    The potential for using conducting polymers as the active material in optoelectronic devices has come to fruition in the past few years. Understanding the fundamental photophysics behind their operations points to the significant role played by the polymer interface in their performance. Current device architectures involve the use of bulk heterojunctions which intimately blend the donor and acceptor polymers to significantly increase not only their interfacial surface area but also the probability of exciton formation within the vicinity of the interface. In this dissertation, we detail the role played by the interface on the behavior and performance of bulk heterojunction systems. First, we explore the relation between the exciton binding energy to the band offset in determining device characteristics. As a general rule, when the exciton binding energy is greater than the band offset, the exciton remains the lowest energy excited state leading to efficient light-emitting properties. On the other hand, if the offset is greater than the binding energy, charge separation becomes favorable leading to better photovoltaic behavior. Here, we use a Wannier function, configuration interaction based approach to examine the essential excited states and predict the vibronic absorption and emission spectra of the PPV/BBL, TFB/F8BT and PFB/F8BT heterojunctions. Our results underscore the role of vibrational relaxation in the formation of charge-transfer states following photoexcitation. In addition, we look at the relaxation dynamics that occur upon photoexcitation. For this, we adopt the Marcus-Hush semiclassical method to account for lattice reorganization in the calculation of the interconversion rates in TFB/F8BT and PFB/F8BT. We find that, while a tightly bound charge-transfer state (exciplex) remains the lowest excited state, a regeneration pathway to the optically active lowest excitonic state in TFB/F8BT is possible via thermal repopulation from the exciplex. Finally

  17. Interference between radiative emission and autoionization in the decay of excited states of atoms

    International Nuclear Information System (INIS)

    Armstrong, L. Jr.; Theodosiou, C.E.; Wall, M.J.

    1978-01-01

    An excited state of an atom which can autoionize can also undergo radiative decay. We consider the interaction between the final states resulting from these two modes of decay, and its effects on such quantities as the fluorescence yield of the excited state, excitation profile of the excited state, and the spectra of the emitted photons and electrons. It is shown that the fraction of decays of the excited state resulting in a photon (fluorescence yield) is particularly sensitive to the details of the final-state interaction. In lowest order in the final-state interaction, the fluorescence yield is increased by a factor (1 + 1/q 2 ) from the traditional value, where q is the Fano q parameter relating to the excited state and the final atomic state

  18. Four-nucleon system with Δ-isobar excitation

    International Nuclear Information System (INIS)

    Deltuva, A.; Fonseca, A.C.; Sauer, P.U.

    2008-01-01

    The four-nucleon bound state and scattering below three-body breakup threshold are described based on the realistic coupled-channel potential CD Bonn+Δ which allows the excitation of a single nucleon to a Δ isobar. The Coulomb repulsion between protons is included. In the four-nucleon system the two-baryon coupled-channel potential yields effective two-, three- and four-nucleon forces, mediated by the Δ isobar and consistent with each other and with the underlying two-nucleon force. The effect of the four-nucleon force on the studied observables is much smaller than the effect of the three-nucleon force. The inclusion of the Δ isobar is unable to resolve the existing discrepancies with the experimental data

  19. The influence of autoionizing states on the excitation of helium by electrons

    International Nuclear Information System (INIS)

    Ittersum, T. van

    1976-01-01

    The work described in this thesis deals with resonance effects in the scattering of electrons by helium at energies near the threshold of the autoionizing states (50-70 eV). The investigation is performed by studying light emission following the excitation of singly excited states. In some cases, the polarization of the radiation was also investigated. The purpose of the research was (i) to enlarge our knowledge of triply excited negative ion states, i.e. resonance states which are formed by temporary binding of the incident electron to a doubly excited (autoionizing) state of neutral helium, and (ii) to clear up the nature of some resonance structures which could not be explained in terms of negative ion resonances

  20. Excited-state relaxation of some aminoquinolines

    Directory of Open Access Journals (Sweden)

    2006-01-01

    Full Text Available The absorption and fluorescence spectra, fluorescence quantum yields and lifetimes, and fluorescence rate constants ( k f of 2-amino-3-( 2 ′ -benzoxazolylquinoline (I, 2-amino-3-( 2 ′ -benzothiazolylquinoline (II, 2-amino-3-( 2 ′ -methoxybenzothiazolyl-quinoline (III, 2-amino-3-( 2 ′ -benzothiazolylbenzoquinoline (IV at different temperatures have been measured. The shortwavelength shift of fluorescence spectra of compounds studied (23–49 nm in ethanol as the temperature decreases (the solvent viscosity increases points out that the excited-state relaxation process takes place. The rate of this process depends essentially on the solvent viscosity, but not the solvent polarity. The essential increasing of fluorescence rate constant k f (up to about 7 times as the solvent viscosity increases proves the existence of excited-state structural relaxation consisting in the mutual internal rotation of molecular fragments of aminoquinolines studied, followed by the solvent orientational relaxation.

  1. Excited-State Dynamics of Carotenoids Studied by Femtosecond Transient Absorption Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ingu; Pang, Yoonsoo [Department of Physics and Photon Science, Gwangju (Korea, Republic of); Lee, Sebok [Gwangju Institute of Science and Technology, Gwangju (Korea, Republic of)

    2014-03-15

    Carotenoids, natural antenna pigments in photosynthesis share a symmetric backbone of conjugated polyenes. Contrary to the symmetric and almost planar geometries of carotenoids, excited state structure and dynamics of carotenoids are exceedingly complex. In this paper, recent infrared and visible transient absorption measurements and excitation dependent dynamics of 8'-apo-β-caroten-8'-al and 7',7'-dicyano-7'-apo-β-carotene will be reviewed. The recent visible transient absorption measurements of 8'-apo-β-caroten-8'-al in polar and nonpolar solvents will also be introduced to emphasize the complex excited-state dynamics and unsolved problems in the S{sub 2} and S{sub 1} excited states.

  2. Excited state dynamics of beta-carotene explored with dispersed multi-pulse transient absorption

    NARCIS (Netherlands)

    Larsen, D.S.; Papagiannakis, E.; van Stokkum, I.H.M.; Vengris, M.; Kennis, J.T.M.; van Grondelle, R.

    2003-01-01

    The excited-state dynamics of β-carotene in hexane was studied with dispersed ultrafast transient absorption techniques. A new excited state is produced after blue-edge excitation. Pump-repump-probe and pump-dump-probe measurements identified and characterized this state, termed S‡, which exhibits a

  3. Quantum entanglement of localized excited states at finite temperature

    Energy Technology Data Exchange (ETDEWEB)

    Caputa, Paweł [Yukawa Institute for Theoretical Physics (YITP), Kyoto University,Kyoto 606-8502 (Japan); Nordita, KTH Royal Institute of Technology and Stockholm University,Roslagstullsbacken 23, SE-106 91 Stockholm (Sweden); Simón, Joan; Štikonas, Andrius [School of Mathematics and Maxwell Institute for Mathematical Sciences,University of Edinburgh,King’s Buildings, Edinburgh EH9 3FD (United Kingdom); Takayanagi, Tadashi [Yukawa Institute for Theoretical Physics (YITP), Kyoto University,Kyoto 606-8502 (Japan); Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU),University of Tokyo,Kashiwa, Chiba 277-8582 (Japan)

    2015-01-20

    In this work we study the time evolutions of (Renyi) entanglement entropy of locally excited states in two dimensional conformal field theories (CFTs) at finite temperature. We consider excited states created by acting with local operators on thermal states and give both field theoretic and holographic calculations. In free field CFTs, we find that the growth of Renyi entanglement entropy at finite temperature is reduced compared to the zero temperature result by a small quantity proportional to the width of the localized excitations. On the other hand, in finite temperature CFTs with classical gravity duals, we find that the entanglement entropy approaches a characteristic value at late time. This behaviour does not occur at zero temperature. We also study the mutual information between the two CFTs in the thermofield double (TFD) formulation and give physical interpretations of our results.

  4. Cross-sections and average angular momenta in fusion reactions near the coulomb barrier

    International Nuclear Information System (INIS)

    Dasgupta, M.

    1992-01-01

    In recent years there has been an increasing interest in the study of heavy ion collisions near the Coulomb barrier. This has been triggered mainly by the observations of enhancements by factors of about one to two order of magnitude in sub-Coulomb barrier fusion (SBF) cross-sections between medium mass nuclei, as compared to predictions based on one-dimensional barrier penetration model (l-d BPM). Though, a considerable amount of work both theoretical and experimental has been done in this field, a complete understanding of the SBF phenomenon has not yet been achieved. The relation between fusion excitation function and angular momentum (l) distribution in SBF reactions is a topic of current interest. It is believed that l-distributions provide a more stringent test of SBF models that the excitation functions alone. Simultaneous measurement of l-distribution (or its moments) and fusion excitation function is expected to lead to a better understanding of the relationship between these two qualities. Such information has been obtained in experiments done at pelletron accelerator facility. In the present talk the measurement of fusion cross-sections and the method of determination of average l from partial evaporation residue cross-section has been elaborated. An analysis of the experimental data on the basis of some of the SBF models has been discussed briefly. (author). 13 refs

  5. Dielectronic recombination rate coefficients to the excited states of CI from CII

    International Nuclear Information System (INIS)

    Dubau, J.; Kato, T.; Safronova, U.I.

    1998-01-01

    The dielectronic recombination rate coefficients to the excited states for n=2-6 are calculated including 1s 2 2l 1 2l 2 2l 3 nl (n=2-6, l≤(n-1)) states. The values for the excited states higher than n=6 are extrapolated and the total dielectronic recombination rate coefficients are derived. The rate coefficients to the excited states are fitted to an analytical formula and the fit parameters are given. (author)

  6. Excited-state dynamics of acetylene excited to individual rotational level of the V04K01 subband

    Science.gov (United States)

    Makarov, Vladimir I.; Kochubei, Sergei A.; Khmelinskii, Igor V.

    2006-01-01

    Dynamics of the IR emission induced by excitation of the acetylene molecule using the (32Ka0,1,2,ÃAu1←41la1,X˜Σg+1) transition was investigated. The observed IR emission was assigned to transitions between the ground-state vibrational levels. Acetylene fluorescence quenching induced by external electric and magnetic fields acting upon the system prepared using the (34Ka1,ÃAu1←00la0,X˜Σg+1) excitation was also studied. External electric field creates an additional radiationless pathway to the ground-state levels, coupling levels of the ÃAu1 excited state to the quasiresonant levels of the X˜Σg+1 ground state. The level density of the ground state in the vicinity of the excited state is very high, thus the electric-field-induced transition is irreversible, with the rate constant described by the Fermi rule. Magnetic field alters the decay profile without changing the fluorescence quantum yield in collisionless conditions. IR emission from the CCH transient was detected, and was also affected by the external electric and magnetic fields. Acetylene predissociation was demonstrated to proceed by the direct S1→S0 mechanism. The results were explained using the previously developed theoretical approach, yielding values of the relevant model parameters.

  7. Excited state properties of aryl carotenoids

    Czech Academy of Sciences Publication Activity Database

    Fuciman, M.; Chábera, P.; Župčanová, Anita; Hříbek, P.; Arellano, J.B.; Vácha, František; Pšenčík, J.; Polívka, Tomáš

    2010-01-01

    Roč. 12, č. 13 (2010), s. 3112-3120 ISSN 1463-9076 R&D Projects: GA AV ČR IAA608170604 Institutional research plan: CEZ:AV0Z50510513 Keywords : carotenoids * excited-states * femtosecond spectroscopy Subject RIV: BO - Biophysics Impact factor: 3.454, year: 2010

  8. Spectroscopic properties of the S1 state of linear carotenoids after excess energy excitation

    Science.gov (United States)

    Kuznetsova, Valentyna; Southall, June; Cogdell, Richard J.; Fuciman, Marcel; Polívka, Tomáš

    2017-09-01

    Properties of the S1 state of neurosporene, spheroidene and lycopene were studied after excess energy excitation in the S2 state. Excitation of carotenoids into higher vibronic levels of the S2 state generates excess vibrational energy in the S1 state. The vibrationally hot S1 state relaxes faster when carotenoid is excited into the S2 state with excess energy, but the S1 lifetime remains constant regardless of which vibronic level of the S2 state is excited. The S∗ signal depends on excitation energy only for spheroidene, which is likely due to asymmetry of the molecule, facilitating conformations responsible for the S∗ signal.

  9. First Double Excitation Cross Sections of Helium Measured for 100-keV Proton Impact

    International Nuclear Information System (INIS)

    Moretto-Capelle, P.; Bordenave-Montesquieu, D.; Bordenave-Montesquieu, A.; Godunov, A.L.; Schipakov, V.A.

    1997-01-01

    Excitation cross sections of the (2s 2 ) 1 S, (2p 2 ) 1 D , and (2s2p) 1 P autoionizing states of helium, produced in collisions with 100-keV protons, have been measured for the first time. Using a high resolution electron spectroscopy together with a recently proposed parametrization of autoionizing resonances distorted by Coulomb interaction in the final state makes it possible to extract from electron spectra total cross sections as well as magnetic sublevel populations. These new experimental data are briefly compared with out theoretical calculations. copyright 1997 The American Physical Society

  10. Measurement of the sign of the spectroscopic quadrupole moment for the 2$_{1}^{+}$ state in $^{70}$Se no evidence for oblate shape

    CERN Document Server

    Hurst, A M

    2007-01-01

    Using a method whereby molecular and atomic ions are independently selected, an isobarically pure beam of 70Se ions was postaccelerated to an energy of 206 MeV using REX-ISOLDE. Coulomb-excitation yields for states in the beam and target nuclei were deduced by recording deexcitation γ rays in the highly segmented MINIBALL γ-ray spectrometer in coincidence with scattered particles in a silicon detector. At these energies, the Coulomb-excitation yield for the first 2+ state is expected to be strongly sensitive to the sign of the spectroscopic quadrupole moment through the nuclear reorientation effect. Experimental evidence is presented here for a prolate shape for the first 2+ state in 70Se, reopening the question over whether there are, as reported earlier, deformed oblate shapes near to the ground state in the light selenium isotopes.

  11. Formation and role of excited states in radiolysis - a foreword

    International Nuclear Information System (INIS)

    Singh, A.

    1976-01-01

    It is stated that the choice of contributions to the special issue of this Journal has been limited to those which bear on the details of the mechanisms of excited state formation and are likely to be useful to radiation chemists. Since more than half the energy deposited in radiolysis goes into excitation, studies on the fate of the excited species formed are very important. A brief reference is made to the subject matter of each of the fifteen contributions, and its significance to the development of the technique of radiolysis is outlined. (U.K.)

  12. Local density approximation for exchange in excited-state density functional theory

    OpenAIRE

    Harbola, Manoj K.; Samal, Prasanjit

    2004-01-01

    Local density approximation for the exchange energy is made for treatment of excited-states in density-functional theory. It is shown that taking care of the state-dependence of the LDA exchange energy functional leads to accurate excitation energies.

  13. Investigating Coulomb's Law.

    Science.gov (United States)

    Noll, Ellis; Koehlinger, Mervin; Kowalski, Ludwik; Swackhamer, Gregg

    1998-01-01

    Describes the use of a computer-linked camera to demonstrate Coulomb's law. Suggests a way of reducing the difficulties in presenting Coulomb's law by teaching the inverse square law of gravity and the inverse square law of electricity in the same unit. (AIM)

  14. Coulomb energy of uniformly charged spheroidal shell systems.

    Science.gov (United States)

    Jadhao, Vikram; Yao, Zhenwei; Thomas, Creighton K; de la Cruz, Monica Olvera

    2015-03-01

    We provide exact expressions for the electrostatic energy of uniformly charged prolate and oblate spheroidal shells. We find that uniformly charged prolate spheroids of eccentricity greater than 0.9 have lower Coulomb energy than a sphere of the same area. For the volume-constrained case, we find that a sphere has the highest Coulomb energy among all spheroidal shells. Further, we derive the change in the Coulomb energy of a uniformly charged shell due to small, area-conserving perturbations on the spherical shape. Our perturbation calculations show that buckling-type deformations on a sphere can lower the Coulomb energy. Finally, we consider the possibility of counterion condensation on the spheroidal shell surface. We employ a Manning-Oosawa two-state model approximation to evaluate the renormalized charge and analyze the behavior of the equilibrium free energy as a function of the shell's aspect ratio for both area-constrained and volume-constrained cases. Counterion condensation is seen to favor the formation of spheroidal structures over a sphere of equal area for high values of shell volume fractions.

  15. Dielectronic recombination rate coefficients to the excited states of CI from CII

    Energy Technology Data Exchange (ETDEWEB)

    Dubau, J. [Observatoire of Paris, 92 MEUDON (France); Kato, T.; Safronova, U.I.

    1998-01-01

    The dielectronic recombination rate coefficients to the excited states for n=2-6 are calculated including 1s{sup 2}2l{sub 1}2l{sub 2}2l{sub 3}nl (n=2-6, l{<=}(n-1)) states. The values for the excited states higher than n=6 are extrapolated and the total dielectronic recombination rate coefficients are derived. The rate coefficients to the excited states are fitted to an analytical formula and the fit parameters are given. (author)

  16. Efficient evaluation of the Coulomb force in the Gaussian and finite-element Coulomb method.

    Science.gov (United States)

    Kurashige, Yuki; Nakajima, Takahito; Sato, Takeshi; Hirao, Kimihiko

    2010-06-28

    We propose an efficient method for evaluating the Coulomb force in the Gaussian and finite-element Coulomb (GFC) method, which is a linear-scaling approach for evaluating the Coulomb matrix and energy in large molecular systems. The efficient evaluation of the analytical gradient in the GFC is not straightforward as well as the evaluation of the energy because the SCF procedure with the Coulomb matrix does not give a variational solution for the Coulomb energy. Thus, an efficient approximate method is alternatively proposed, in which the Coulomb potential is expanded in the Gaussian and finite-element auxiliary functions as done in the GFC. To minimize the error in the gradient not just in the energy, the derived functions of the original auxiliary functions of the GFC are used additionally for the evaluation of the Coulomb gradient. In fact, the use of the derived functions significantly improves the accuracy of this approach. Although these additional auxiliary functions enlarge the size of the discretized Poisson equation and thereby increase the computational cost, it maintains the near linear scaling as the GFC and does not affects the overall efficiency of the GFC approach.

  17. Yang-Mills theory in Coulomb gauge; Yang-Mills-theorie in Coulombeichung

    Energy Technology Data Exchange (ETDEWEB)

    Feuchter, C.

    2006-07-01

    In this thesis we study the Yang-Mills vacuum structure by using the functional Schroedinger picture in Coulomb gauge. In particular we discuss the scenario of colour confinement, which was originally formulated by Gribov. After a short introduction, we recall some basic aspects of Yang-Mills theories, its canonical quantization in the Weyl gauge and the functional Schroedinger picture. We then consider the minimal Coulomb gauge and the Gribov problem of the gauge theory. The gauge fixing of the Coulomb gauge is done by using the Faddeev-Popov method, which enables the resolution of the Gauss law - the constraint on physical states. In the third chapter, we variationally solve the stationary Yang-Mills Schroedinger equation in Coulomb gauge for the vacuum state. Therefor we use a vacuum wave functional, which is strongly peaked at the Gribov horizon. The vacuum energy functional is calculated and minimized resulting in a set of coupled Schwinger-Dyson equations for the gluon energy, the ghost and Coulomb form factors and the curvature in gauge orbit space. Using the angular approximation these integral equations have been solved analytically in both the infrared and the ultraviolet regime. The asymptotic analytic solutions in the infrared and ultraviolet regime are reasonably well reproduced by the full numerical solutions of the coupled Schwinger-Dyson equations. In the fourth chapter, we investigate the dependence of the Yang-Mills wave functional in Coulomb gauge on the Faddeev-Popov determinant. (orig.)

  18. Diffusion in Coulomb crystals.

    Science.gov (United States)

    Hughto, J; Schneider, A S; Horowitz, C J; Berry, D K

    2011-07-01

    Diffusion in Coulomb crystals can be important for the structure of neutron star crusts. We determine diffusion constants D from molecular dynamics simulations. We find that D for Coulomb crystals with relatively soft-core 1/r interactions may be larger than D for Lennard-Jones or other solids with harder-core interactions. Diffusion, for simulations of nearly perfect body-centered-cubic lattices, involves the exchange of ions in ringlike configurations. Here ions "hop" in unison without the formation of long lived vacancies. Diffusion, for imperfect crystals, involves the motion of defects. Finally, we find that diffusion, for an amorphous system rapidly quenched from Coulomb parameter Γ=175 to Coulomb parameters up to Γ=1750, is fast enough that the system starts to crystalize during long simulation runs. These results strongly suggest that Coulomb solids in cold white dwarf stars, and the crust of neutron stars, will be crystalline and not amorphous.

  19. Excited-state Raman spectroscopy with and without actinic excitation: S1 Raman spectra of trans-azobenzene

    International Nuclear Information System (INIS)

    Dobryakov, A. L.; Quick, M.; Ioffe, I. N.; Granovsky, A. A.; Ernsting, N. P.; Kovalenko, S. A.

    2014-01-01

    We show that femtosecond stimulated Raman spectroscopy can record excited-state spectra in the absence of actinic excitation, if the Raman pump is in resonance with an electronic transition. The approach is illustrated by recording S 1 and S 0 spectra of trans-azobenzene in n-hexane. The S 1 spectra were also measured conventionally, upon nπ* (S 0 → S 1 ) actinic excitation. The results are discussed and compared to earlier reports

  20. Electronic and Structural Properties of ABO3: Role of the B-O Coulomb Repulsions for Ferroelectricity.

    Science.gov (United States)

    Miura, Kaoru; Azuma, Masaki; Funakubo, Hiroshi

    2011-01-17

    We have investigated the role of the Ti-O Coulomb repulsions in the appearance of the ferroelectric state in BaTiO3 as well as the role of the Zn-O Coulomb repulsions in BiZn0.5Ti0.5O3, using a first-principles calculation with optimized structures. In tetragonal BaTiO3, it is found that the Coulomb repulsions between Ti 3s and 3p states and O 2s and 2p states have an important role for the appearance of Ti ion displacement. In BiZn0.5Ti0.5O3, on the other hand, the stronger Zn-O Coulomb repulsions, which are due to the 3s, 3p, and 3d (d10) states of the Zn ion, have more important role than the Ti-O Coulomb repulsions for the appearance of the tetragonal structure. Our suggestion is consistent with the other ferroelectric perovskite oxides ABO3 in the appearance of tetragonal structures as well as rhombohedral structures.

  1. Hyperspherical Coulomb spheroidal basis in the Coulomb three-body problem

    International Nuclear Information System (INIS)

    Abramov, D. I.

    2013-01-01

    A hyperspherical Coulomb spheroidal (HSCS) representation is proposed for the Coulomb three-body problem. This is a new expansion in the set of well-known Coulomb spheroidal functions. The orthogonality of Coulomb spheroidal functions on a constant-hyperradius surface ρ = const rather than on a constant-internuclear-distance surface R = const, as in the traditional Born-Oppenheimer approach, is a distinguishing feature of the proposed approach. Owing to this, the HSCS representation proves to be consistent with the asymptotic conditions for the scattering problem at energies below the threshold for three-body breakup: only a finite number of radial functions do not vanish in the limit of ρ→∞, with the result that the formulation of the scattering problem becomes substantially simpler. In the proposed approach, the HSCS basis functions are considerably simpler than those in the well-known adiabatic hyperspherical representation, which is also consistent with the asymptotic conditions. Specifically, the HSCS basis functions are completely factorized. Therefore, there arise no problems associated with avoided crossings of adiabatic hyperspherical terms.

  2. Universal monopole scaling near transitions from the Coulomb phase.

    Science.gov (United States)

    Powell, Stephen

    2012-08-10

    Certain frustrated systems, including spin ice and dimer models, exhibit a Coulomb phase at low temperatures, with power-law correlations and fractionalized monopole excitations. Transitions out of this phase, at which the effective gauge theory becomes confining, provide examples of unconventional criticality. This Letter studies the behavior at nonzero monopole density near such transitions, using scaling theory to arrive at universal expressions for the crossover phenomena. For a particular transition in spin ice, quantitative predictions are made by mapping to the XY model and confirmed using Monte Carlo simulations.

  3. Heavy-ion transfer to high-spin states

    International Nuclear Information System (INIS)

    Lauterbach, C.

    1985-01-01

    Transfer reactions between very heavy ions, in particular about systems in which one or both collision partners are well deformed, are studied. These systems are expected to give rise to new phenomena which are related to the fact that the deformed nucleus has been Coulomb excited to a rotational or vibrational state at the time when the collision partners come into contact. In this paper the authors present results of experiments in which nuclei from the rare earth and the actinide region have been bombarded by various projectiles ranging from 34 S to 208 Pb at incident energies close to the Coulomb barrier. (Auth.)

  4. Microscopic description and excitation of unitary analog states

    Energy Technology Data Exchange (ETDEWEB)

    Kisslinger, L S [Carnegie-Mellon Univ., Pittsburgh, Pa. (USA); Van Giai, N [Paris-11 Univ., 91 - Orsay (France). Inst. de Physique Nucleaire

    1977-12-05

    A microscopic investigation in a self-consistent particle-hole model reveals approximate unitary analog states in spite of large symmetry breaking. The K-nucleus elastic scattering and (K/sup -/, ..pi../sup -/) excitation of these states are studied, showing strong surface effects.

  5. Ultrafast electronic relaxation of excited state vitamin B12 in the gas phase

    International Nuclear Information System (INIS)

    Shafizadeh, Niloufar; Poisson, Lionel; Soep, Benoit

    2008-01-01

    The time evolution of electronically excited vitamin B 12 (cyanocobalamin) has been observed for the first time in the gas phase. It reveals an ultrafast decay to a state corresponding to metal excitation. This decay is interpreted as resulting from a ring to metal electron transfer. This opens the observation of the excited state of other complex biomimetic systems in the gas phase, the key to the characterisation of their complex evolution through excited electronic states

  6. Coulomb Excitation of Neutron-Rich $A\\approx$140 Nuclei

    CERN Multimedia

    Van duppen, P L E

    2002-01-01

    Investigating the isospin dependence of the product between the B( E2; 0$_{1}^{+} \\rightarrow 2_{1}^{+}$)-value and the 2$_{1}^{+}$-excitation energy E$_{2^{+}}$ in even-even nuclei around $A\\!\\approx$140 one observes a rather smooth trend close to the valley of stability but clear indication for a reduction from the extrapolated B(E2)-values by one order of magnitude for some very neutron-rich nuclei. While close to the valley of stability the strong neutron-proton interaction results in an equilibration of the neutron and proton deformations with a predominate isoscalar character of the collective 2$^{+}$ excitation, it is conceivable that more loosely bound neutrons cannot polarize a close-to-magic proton core that well any more. This might result in a decoupling of the shape of the outer neutrons from the core and in a strong isovector admixture to the lowest lying 2$^{+}$ level. In this way the 2$^{+}$ -energies could be further lowered in neutron-rich nuclei, while the quadrupole moments of the proton c...

  7. First 3- excited state of 56Fe

    International Nuclear Information System (INIS)

    Fotiades, N.; Nelson, R. O.; Devlin, M.

    2010-01-01

    There is no reliable evidence for the existence of the 3.076 MeV (3 - ) level adopted in the ENSDF evaluation for 56 Fe although it has been reported in a few experiments. Previous reports of the observation of this level appear to be based on an incorrect assignment in early (e,e ' ) work. Recent neutron inelastic scattering measurements by Demidov et al. [Phys. At. Nucl. 67, 1884, (2004)] show that the assigned γ-ray decay of this state does not occur at a level consistent with known properties of inelastic scattering. In the present work the 56 Fe(n,n ' γ) reaction was used to populate excited states in 56 Fe. Neutrons in the energy range from 1 to 250 MeV were provided by the pulsed neutron source of the Los Alamos Neutron Science Center's WNR facility. Deexciting γ rays were detected with the GEANIE spectrometer, a Compton suppressed array of 26 Ge detectors. The γ-γ data obtained with GEANIE were used to establish coincidence relations between transitions. All previously reported levels up to E x =3.6 MeV excitation energy were observed except for the 3.076 MeV (3 - ) level. The 991- and 2229-keV transitions, previously reported to deexcite this level, were not observed in the γ-γ coincidence data obtained in the present experiment. The present work supports the assignment of the 4509.6 keV level as the first 3 - excited state in 56 Fe by observation of two previously known transitions deexciting this state.

  8. Monotonicity and concavity in Coulomb systems

    International Nuclear Information System (INIS)

    Englisch, R.; Englisch, H.; Karl-Marx-Universitaet, Leipzig

    1986-01-01

    The eigenvalues of H(α) = H 0 + αH * , where H * is an arbitrary Coulomb potential, decrease with increasing α ≥ 0. Linear and parabolic bounds for the ground state energy are presented. These bounds are applied to the biexciton and the exciton at a neutral donor. (orig.)

  9. Excited State Structural Dynamics of Carotenoids and ChargeTransfer Systems

    Energy Technology Data Exchange (ETDEWEB)

    Van Tassle, Aaron Justin [Univ. of California, Berkeley, CA (United States)

    2006-01-01

    This dissertation describes the development andimplementation of a visible/near infrared pump/mid-infrared probeapparatus. Chapter 1 describes the background and motivation ofinvestigating optically induced structural dynamics, paying specificattention to solvation and the excitation selection rules of highlysymmetric molecules such as carotenoids. Chapter 2 describes thedevelopment and construction of the experimental apparatus usedthroughout the remainder of this dissertation. Chapter 3 will discuss theinvestigation of DCM, a laser dye with a fluorescence signal resultingfrom a charge transfer state. By studying the dynamics of DCM and of itsmethyl deuterated isotopomer (an otherwise identical molecule), we areable to investigate the origins of the charge transfer state and provideevidence that it is of the controversial twisted intramolecular (TICT)type. Chapter 4 introduces the use of two-photon excitation to the S1state, combined with one-photon excitation to the S2 state of thecarotenoid beta-apo-8'-carotenal. These 2 investigations show evidencefor the formation of solitons, previously unobserved in molecular systemsand found only in conducting polymers Chapter 5 presents an investigationof the excited state dynamics of peridinin, the carotenoid responsiblefor the light harvesting of dinoflagellates. This investigation allowsfor a more detailed understanding of the importance of structuraldynamics of carotenoids in light harvesting.

  10. Stability of quantum-dot excited-state laser emission under simultaneous ground-state perturbation

    Energy Technology Data Exchange (ETDEWEB)

    Kaptan, Y., E-mail: yuecel.kaptan@physik.tu-berlin.de; Herzog, B.; Schöps, O.; Kolarczik, M.; Woggon, U.; Owschimikow, N. [Institut für Optik und Atomare Physik, Technische Universität Berlin, Berlin (Germany); Röhm, A.; Lingnau, B.; Lüdge, K. [Institut für Theoretische Physik, Technische Universität Berlin, Berlin (Germany); Schmeckebier, H.; Arsenijević, D.; Bimberg, D. [Institut für Festkörperphysik, Technische Universität Berlin, Berlin (Germany); Mikhelashvili, V.; Eisenstein, G. [Technion Institute of Technology, Faculty of Electrical Engineering, Haifa (Israel)

    2014-11-10

    The impact of ground state amplification on the laser emission of In(Ga)As quantum dot excited state lasers is studied in time-resolved experiments. We find that a depopulation of the quantum dot ground state is followed by a drop in excited state lasing intensity. The magnitude of the drop is strongly dependent on the wavelength of the depletion pulse and the applied injection current. Numerical simulations based on laser rate equations reproduce the experimental results and explain the wavelength dependence by the different dynamics in lasing and non-lasing sub-ensembles within the inhomogeneously broadened quantum dots. At high injection levels, the observed response even upon perturbation of the lasing sub-ensemble is small and followed by a fast recovery, thus supporting the capacity of fast modulation in dual-state devices.

  11. Embedding potentials for excited states of embedded species

    International Nuclear Information System (INIS)

    Wesolowski, Tomasz A.

    2014-01-01

    Frozen-Density-Embedding Theory (FDET) is a formalism to obtain the upper bound of the ground-state energy of the total system and the corresponding embedded wavefunction by means of Euler-Lagrange equations [T. A. Wesolowski, Phys. Rev. A 77(1), 012504 (2008)]. FDET provides the expression for the embedding potential as a functional of the electron density of the embedded species, electron density of the environment, and the field generated by other charges in the environment. Under certain conditions, FDET leads to the exact ground-state energy and density of the whole system. Following Perdew-Levy theorem on stationary states of the ground-state energy functional, the other-than-ground-state stationary states of the FDET energy functional correspond to excited states. In the present work, we analyze such use of other-than-ground-state embedded wavefunctions obtained in practical calculations, i.e., when the FDET embedding potential is approximated. Three computational approaches based on FDET, that assure self-consistent excitation energy and embedded wavefunction dealing with the issue of orthogonality of embedded wavefunctions for different states in a different manner, are proposed and discussed

  12. On the effects on a Landau-type system for an atom with no permanent electric dipole moment due to a Coulomb-type potential

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Abinael B.; Bakke, Knut, E-mail: kbakke@fisica.ufpb.br

    2016-02-15

    We analyse the bound states for a Landau-type system for an atom with no permanent electric dipole moment subject to a Coulomb-type potential. By comparing the energy levels for bound states of the system with the Landau quantization for an atom with no permanent electric dipole moment (Furtado et al., 2006), we show that the energy levels of the Landau-type system are modified, where the degeneracy of the energy levels is broken. Another quantum effect investigated is a dependence of the angular frequency of the system on the quantum numbers associated with the radial modes and the angular momentum. As examples, we obtain the angular frequency and the energy levels associated with the ground state and the first excited state of the system.

  13. On the effects on a Landau-type system for an atom with no permanent electric dipole moment due to a Coulomb-type potential

    International Nuclear Information System (INIS)

    Oliveira, Abinael B.; Bakke, Knut

    2016-01-01

    We analyse the bound states for a Landau-type system for an atom with no permanent electric dipole moment subject to a Coulomb-type potential. By comparing the energy levels for bound states of the system with the Landau quantization for an atom with no permanent electric dipole moment (Furtado et al., 2006), we show that the energy levels of the Landau-type system are modified, where the degeneracy of the energy levels is broken. Another quantum effect investigated is a dependence of the angular frequency of the system on the quantum numbers associated with the radial modes and the angular momentum. As examples, we obtain the angular frequency and the energy levels associated with the ground state and the first excited state of the system.

  14. Selective excitation of atoms or molecules to high-lying states

    International Nuclear Information System (INIS)

    Ducas, T.W.

    1978-01-01

    This specification relates to the selective excitation of atoms or molecules to high lying states and a method of separating different isotopes of the same element by selective excitation of the isotopes. (U.K.)

  15. Influence of ion induced local Coulomb field and polarity on charge generation and efficiency in poly(3-hexylthiophene)-based solid-state dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Abrusci, Agnese; Snaith, Henry J. [Clarendon Laboratory, Department of Physics, University of Oxford (United Kingdom); Santosh Kumar, R. Sai; Petrozza, Annamaria [Center for Nano Science and Technology of IIT, Milano (Italy); Al-Hashimi, Mohammed; Heeney, Martin [Department of Chemistry and Centre for Plastic Electronics, Imperial College London (United Kingdom)

    2011-07-08

    Dye-sensitized solar cells (DSSC) are a realistic option for converting light to electrical energy. Hybrid architectures offer a vast materials library for device optimization, including a variety of metal oxides, organic and inorganic sensitizers, molecular, polymeric and electrolytic hole-transporter materials. In order to further improve the efficiency of solid-state dye-sensitized solar cells, recent attention has focused on using light absorbing polymers such as poly(3-hexylthiophene) (P3HT), to replace the more commonly used ''transparent'' 2,2',7,7'-tetrakis-(N,N-di-p-methoxyphenyl-amine)9,9'spiro-bifluorene (spiro-OMeTAD), in order to enhance the light absorption within thin films. As is the case with spiro-OMeTAD based solid-state DSSC, the P3HT-based devices improve significantly with the addition of lithium bis(trifluoromethylsulfonyl)imide salts (Li-TFSI), although the precise role of these additives has not yet been clarified in solid-state DSCs. Here, we present a thorough study on the effect of Li-TFSI in P3HT based solid-state DSSC incorporating an indolene-based organic sensitizer termed D102. Employing ultrafast transient absorption and cw-emission spectroscopy together with electronic measurements, we demonstrate a fine tuning of the energetic landscape of the active cell components by the local Coulomb field induced by the ions. This increases the charge transfer nature of the excited state on the dye, significantly accelerating electron injection into the TiO{sub 2}. We demonstrate that this ionic influence on the excited state energy is the primary reason for enhanced charge generation with the addition of ionic additives. The deepening of the relative position of the TiO{sub 2} conduction band, which has previously been thought to be the cause for enhanced charge generation in dye sensitized solar cells with the addition of lithium salts, appears to be of minor importance in this system. (Copyright copyright

  16. Does the excited state of the 3He nucleus exist?

    International Nuclear Information System (INIS)

    Barabanov, A.L.

    1994-01-01

    The suggestion is made that the excited state of the 3 He nucleus found out recently in the reaction has spin and parity 1/2 + and the same configuration that the ground open of 6 He. It is shown that in an elastic nd-scattering a resonance associated with the excited state may be absent due to destructive interference of potential and resonant scattering phases

  17. Gauge orbits and the Coulomb potential

    International Nuclear Information System (INIS)

    Greensite, J.

    2009-01-01

    If the color Coulomb potential is confining, then the Coulomb field energy of an isolated color charge is infinite on an infinite lattice, even if the usual UV divergence is lattice regulated. A simple criterion for Coulomb confinement is that the expectation value of timelike link variables vanishes in the Coulomb gauge, but it is unclear how this criterion is related to the spectrum of the corresponding Faddeev-Popov operator, which can be used to formulate a quite different criterion for Coulomb confinement. The purpose of this article is to connect the two seemingly different Coulomb confinement criteria, and explain the geometrical basis of the connection.

  18. A benchmark study of electronic excitation energies, transition moments, and excited-state energy gradients on the nicotine molecule

    Energy Technology Data Exchange (ETDEWEB)

    Egidi, Franco, E-mail: franco.egidi@sns.it; Segado, Mireia; Barone, Vincenzo, E-mail: vincenzo.barone@sns.it [Scuola Normale Superiore, Piazza dei Cavalieri, 7 I-56126 Pisa (Italy); Koch, Henrik [Department of Chemistry, Norwegian University of Science and Technology, 7491 Trondheim (Norway); Cappelli, Chiara [Dipartimento di Chimica e Chimica Industriale, Università di Pisa, via G. Moruzzi, 3 I-56124 Pisa (Italy)

    2014-12-14

    In this work, we report a comparative study of computed excitation energies, oscillator strengths, and excited-state energy gradients of (S)-nicotine, chosen as a test case, using multireference methods, coupled cluster singles and doubles, and methods based on time-dependent density functional theory. This system was chosen because its apparent simplicity hides a complex electronic structure, as several different types of valence excitations are possible, including n-π{sup *}, π-π{sup *}, and charge-transfer states, and in order to simulate its spectrum it is necessary to describe all of them consistently well by the chosen method.

  19. Supersymmetric quantum mechanics and higher excited states of a non-polynomial potential

    International Nuclear Information System (INIS)

    Drigo Filho, E.; Ricotta, R.M.

    1989-03-01

    Supersymmetric quantum mechanics is used to evaluate new excited states of a non-polynomial potential. This illustrates a method of evaluating higher excited states of quantum mechanical potentials. (A.C.A.S.) [pt

  20. A uniform semi-classical approach to the Coulomb fission problem

    International Nuclear Information System (INIS)

    Levit, S.; Smilansky, U.

    1978-01-01

    A semi-classical theory based on the path integral formalism is applied to the description of Coulomb fission. Complex classical trajectories are used to compute the classically forbidden transitions from the target's ground state to fission. In a simple model the energy spectrum and angular distributions of the fragments are calculated for the Coulomb fission in the Xe + U collision. Theoretical predictions are made which may be checked experimentally. (author)

  1. Periodicity and chaos in strongly perturbed classical orbitals for Coulomb interactions

    Energy Technology Data Exchange (ETDEWEB)

    Klar, H

    1986-01-01

    Within the framework of classical mechanics two prototypes of strongly perturbed orbitals, the diamagnetism in hydrogen and electronic double excitation, are analyzed near critical phase space points (fixed points). The motion of the hydrogen electron under the joint influence of the Coulomb field and the magnetic field is periodic for any field strengths. For a two-electron atom however the author finds a chaotic time evolution of the electron pair correlation, causing presumably irregular spectral patterns. (Auth.).

  2. Competition between excited core states and 1homega single-particle excitations at comparable energies in {sup 207}Pb from photon scattering

    Energy Technology Data Exchange (ETDEWEB)

    Pietralla, N., E-mail: pietralla@ikp.tu-darmstadt.d [Institut fuer Kernphysik, Technische Universitaet Darmstadt, 64289 Darmstadt (Germany); Nuclear Structure Laboratory, SUNY at Stony Brook, Stony Brook, NY 11794-3800 (United States); Institut fuer Kernphysik, Universitaet zu Koeln, 50937 Koeln (Germany); Li, T.C. [Nuclear Structure Laboratory, SUNY at Stony Brook, Stony Brook, NY 11794-3800 (United States); Fritzsche, M. [Institut fuer Kernphysik, Technische Universitaet Darmstadt, 64289 Darmstadt (Germany); Ahmed, M.W. [Triangle Universities Nuclear Laboratory (TUNL), Duke University, Durham, NC 27708 (United States); Ahn, T.; Costin, A. [Institut fuer Kernphysik, Technische Universitaet Darmstadt, 64289 Darmstadt (Germany); Nuclear Structure Laboratory, SUNY at Stony Brook, Stony Brook, NY 11794-3800 (United States); Institut fuer Kernphysik, Universitaet zu Koeln, 50937 Koeln (Germany); Enders, J. [Institut fuer Kernphysik, Technische Universitaet Darmstadt, 64289 Darmstadt (Germany); Li, J. [Duke Free Electron Laser Laboratory (DFELL), Duke University, Durham, NC 27708 (United States); Mueller, S.; Neumann-Cosel, P. von [Institut fuer Kernphysik, Technische Universitaet Darmstadt, 64289 Darmstadt (Germany); Pinayev, I.V. [Duke Free Electron Laser Laboratory (DFELL), Duke University, Durham, NC 27708 (United States); Ponomarev, V.Yu.; Savran, D. [Institut fuer Kernphysik, Technische Universitaet Darmstadt, 64289 Darmstadt (Germany); Tonchev, A.P.; Tornow, W.; Weller, H.R. [Triangle Universities Nuclear Laboratory (TUNL), Duke University, Durham, NC 27708 (United States); Werner, V. [A.W. Wright Nuclear Structure Laboratory (WNSL), Yale University, New Haven, CT (United States); Wu, Y.K. [Duke Free Electron Laser Laboratory (DFELL), Duke University, Durham, NC 27708 (United States); Zilges, A. [Institut fuer Kernphysik, Universitaet zu Koeln, 50937 Koeln (Germany)

    2009-10-26

    The Pb(gamma{sup -}>,gamma{sup '}) photon scattering reaction has been studied with the nearly monochromatic, linearly polarized photon beams at the High Intensity gamma-ray Source (HIgammaS) at the DFELL. Azimuthal scattering intensity asymmetries measured with respect to the polarization plane of the beam have been used for the first time to assign both the spin and parity quantum numbers of dipole excited states of {sup 206,207,208}Pb at excitation energies in the vicinity of 5.5 MeV. Evidence for dominant particle-core coupling is deduced from these results along with information on excitation energies and electromagnetic transition matrix elements. Implications of the existence of weakly coupled states built on highly excited core states in competition with 1homega single particle (hole) excitations at comparable energies are discussed.

  3. The properties of 4'-N,N-dimethylaminoflavonol in the ground and excited states

    Science.gov (United States)

    Moroz, V. V.; Chalyi, A. G.; Roshal, A. D.

    2008-09-01

    The mechanism of protonation of 4-N,N-dimethylaminoflavonol and the structure of its protolytic forms in the ground and excited states were studied by electron absorption and fluorescence (steady-state and time-resolved) spectroscopy and with the use of the RM1 quantum-chemical method. A comparison of equilibrium constants and the theoretical enthalpies of formation showed that excitation should be accompanied by the inversion of the basicity of the electron acceptor groups of this compound and, as a consequence, changes in the structure of its monocationic form. An analysis of the spectral parameters of the protolytic 4-N,N-dimethylaminoflavonol forms, however, showed that their structure and the sequence of protonation in the excited state were the same as in the ground state. Changes in the structure of the monocation in the excited state were not observed because of the fast radiationless deactivation of this form and the occurrence of excited state intramolecular proton transfer in aprotic solvents.

  4. The quadrupole moment of the first 3- state in 208Pb

    International Nuclear Information System (INIS)

    Joye, A.M.R.; Baxter, A.M.; Fewell, M.P.; Kean, D.C.; Spear, R.H.

    1977-04-01

    The B(E3; 0 + →3 - ) and quadrupole moment, Qsub(3 - ), of the first excited state of 208 Pb have been measured by the reorientation effect in Coulomb excitation, giving B(E3; 0 + →3 - ) = 0.665 +- E 2 B 3 and Qsub(3 - ) = -0.42 +- 0.32 EB. This value for Qsub(3 - ) is much smaller in magnitude than those obtained by Barnett et al., and is consistent with most theoretical predictions. (Author)

  5. Elastic Coulomb breakup of 34Na

    Science.gov (United States)

    Singh, G.; Shubhchintak, Chatterjee, R.

    2016-08-01

    Background: 34Na is conjectured to play an important role in the production of seed nuclei in the alternate r -process paths involving light neutron rich nuclei very near the β -stability line, and as such, it is important to know its ground state properties and structure to calculate rates of the reactions it might be involved in, in the stellar plasma. Found in the region of `island of inversion', its ground state might not be in agreement with normal shell model predictions. Purpose: The aim of this paper is to study the elastic Coulomb breakup of 34Na on 208Pb to give us a core of 33Na with a neutron and in the process we try and investigate the one neutron separation energy and the ground state configuration of 34Na. Method: A fully quantum mechanical Coulomb breakup theory within the architecture of post-form finite range distorted wave Born approximation extended to include the effects of deformation is used to research the elastic Coulomb breakup of 34Na on 208Pb at 100 MeV/u. The triple differential cross section calculated for the breakup is integrated over the desired components to find the total cross-section, momentum, and angular distributions as well as the average momenta, along with the energy-angular distributions. Results: The total one neutron removal cross section is calculated to test the possible ground state configurations of 34Na. The average momentum results along with energy-angular calculations indicate 34Na to have a halo structure. The parallel momentum distributions with narrow full widths at half-maxima signify the same. Conclusion: We have attempted to analyze the possible ground state configurations of 34Na and in congruity with the patterns in the `island of inversion' conclude that even without deformation, 34Na should be a neutron halo with a predominant contribution to its ground state most probably coming from 33Na(3 /2+)⊗ 2 p3 /2ν configuration. We also surmise that it would certainly be useful and rewarding to test our

  6. Optimal control of peridinin excited-state dynamics

    Czech Academy of Sciences Publication Activity Database

    Dietzek, B.; Chábera, P.; Hanf, R.; Tschierlei, S.; Popp, J.; Pascher, T.; Yartsev, A.; Polívka, Tomáš

    2010-01-01

    Roč. 373, 1-2 (2010), s. 129-136 ISSN 0301-0104 Institutional research plan: CEZ:AV0Z50510513 Keywords : peridin * excited-state dynamics * coherent control Subject RIV: BO - Biophysics Impact factor: 2.017, year: 2010

  7. Theory of superconductivity and spin excitations in cuprates

    Science.gov (United States)

    Plakida, Nikolay M.

    2018-06-01

    A microscopic theory of high-temperature superconductivity in strongly correlated systems as cuprates is presented. The two-subband extended Hubbard model is considered where the intersite Coulomb repulsion and electron-phonon interaction are taken into account. The low-energy spin excitations are considered within the t-J model.

  8. Expansions for Coulomb wave functions

    NARCIS (Netherlands)

    Boersma, J.

    1969-01-01

    In this paper we derive a number of expansions for Whittaker functions, regular and irregular Coulomb wave functions. The main result consists of a new expansion for the irregular Coulomb wave functions of orders zero and one in terms of regular Coulomb wave functions. The latter expansions are

  9. Anisotropy of electronic states excited in ion-atom collisions

    International Nuclear Information System (INIS)

    Boskamp, E.B.

    1983-01-01

    The author reports coincidence measurements made on the He + + Ne and He + + He systems. The complex population amplitudes for the magnetic sublevels of the investigated excited states, Ne(2p 4 3s 2 ) 1 D and He(2p 2 ) 1 D, were completely determined and possible excitation mechanisms are described. (Auth.)

  10. Coulomb dissociation reactions on molybdenum isotopes for astrophysics applications

    Energy Technology Data Exchange (ETDEWEB)

    Ershova, Olga

    2012-03-09

    Within the present work, photodissociation reactions on {sup 100}Mo, {sup 93}Mo and {sup 92}Mo isotopes were studied by means of the Coulomb dissociation method at the LAND setup at GSI. As a result of the analysis of the present experiment, integrated Coulomb excitation cross sections of the {sup 100}Mo({gamma},n), {sup 100}Mo({gamma},2n), {sup 93}Mo({gamma},n) and {sup 92}Mo({gamma},n) reactions were determined. A second important topic of the present thesis is the investigation of the efficiency of the CsI gamma detector. The data taken with the gamma calibration sources shortly after the experiment were used for the investigation. In addition, a test experiment in refined conditions was conducted within the framework of this thesis. Numerous GEANT3 simulations of the detector were performed in order to understand various aspects of its performance. As a result, the efficiency of the detector was determined to be approximately a factor of 2 lower than the efficiency expected from the simulation. (orig.)

  11. Can $\\beta$-decay probe excited state halos?

    CERN Multimedia

    2002-01-01

    In the first experiment at the newly constructed ISOLDE Facility the first-forbidden $\\beta$-decay of $^{17}$Ne into the first excited state of $^{17}$F has been measured. It is a factor two faster than the corresponding mirror decay and thus gives one of the largest recorded asymmetries for $\\beta$-decays feeding bound final states. Shell-model calculations can only reproduce the asymmetry if the halo structure of the $^{17}$F state is taken into account.

  12. Coulomb corrections to scattering length and effective radius

    International Nuclear Information System (INIS)

    Mur, V.D.; Kudryavtsev, A.E.; Popov, V.S.

    1983-01-01

    The problem considered is extraction of the ''purely nuclear'' scattering length asub(s) (corresponding to the strong potential Vsub(s) at the Coulomb interaction switched off) from the Coulomb-nuclear scattering length asub(cs), which is an object of experimental measurement. The difference between asub(s) and asub(cs) is especially large if the potential Vsub(s) has a level (real or virtual) with an energy close to zero. For this case formulae are obtained relating the scattering lengths asub(s) and asub(cs), as well as the effective radii rsub(s) and rsub(cs). The results are extended to states with arbitrary angular momenta l. It is shown that the Coulomb correction is especially large for the coefficient with ksup(2l) in the expansion of the effective radius; in this case the correction contains a large logarithm ln(asub(B)/rsub(0)). The Coulomb renormalization of other terms in the effective radius espansion is of order (rsub(0)/asub(B)), where r 0 is the nuclear force radius, asub(B) is the Bohr radius. The obtained formulae are tried on a number of model potentials Vsub(s), used in nuclear physics

  13. Spectroscopic Diagnosis of Excited-State Aromaticity: Capturing Electronic Structures and Conformations upon Aromaticity Reversal.

    Science.gov (United States)

    Oh, Juwon; Sung, Young Mo; Hong, Yongseok; Kim, Dongho

    2018-03-06

    Aromaticity, the special energetic stability derived from cyclic [4 n + 2]π-conjugated electronic structures, has been the topic of intense interest in chemistry because it plays a critical role in rationalizing molecular stability, reactivity, and physical/chemical properties. Recently, the pioneering work by Colin Baird on aromaticity reversal, postulating that aromatic (antiaromatic) character in the ground state reverses to antiaromatic (aromatic) character in the lowest excited triplet state, has attracted much scientific attention. The completely reversed aromaticity in the excited state provides direct insight into understanding the photophysical/chemical properties of photoactive materials. In turn, the application of aromatic molecules to photoactive materials has led to numerous studies revealing this aromaticity reversal. However, most studies of excited-state aromaticity have been based on the theoretical point of view. The experimental evaluation of aromaticity in the excited state is still challenging and strenuous because the assessment of (anti)aromaticity with conventional magnetic, energetic, and geometric indices is difficult in the excited state, which practically restricts the extension and application of the concept of excited-state aromaticity. Time-resolved optical spectroscopies can provide a new and alternative avenue to evaluate excited-state aromaticity experimentally while observing changes in the molecular features in the excited states. Time-resolved optical spectroscopies take advantage of ultrafast laser pulses to achieve high time resolution, making them suitable for monitoring ultrafast changes in the excited states of molecular systems. This can provide valuable information for understanding the aromaticity reversal. This Account presents recent breakthroughs in the experimental assessment of excited-state aromaticity and the verification of aromaticity reversal with time-resolved optical spectroscopic measurements. To

  14. Generalized Coulomb gauge without Gribov ambiguity

    Energy Technology Data Exchange (ETDEWEB)

    Fachin, S.; Parrinello, C. (New York Univ., NY (United States). Physics Dept.)

    1992-05-01

    We discuss a global gauge-fixing prescription that is free of the Gribov problem, preserves reflection positivity and contains as a limiting case the (maximal) Coulomb gauge. In such a formalism it is very easy to check that only color singlet states propagate in Euclidean time, for any value of [beta]. (orig.).

  15. Production of autoionizing di-excited states of barium with high angular momentum

    International Nuclear Information System (INIS)

    Roussel, F.; Breger, P.; Gounand, F.; Spiess, G.

    1988-01-01

    Autoionizing di-excited states Ba(6p 1/2 27l) with 7 ≤l≤26, have been experimentally detected. They have been produced by a method combining excitation by two lasers and l-mixing collisions between barium and xenon. Results show that a long delay between the two laser excitation steps is favourable to the production of these states. The method has proved to be very efficient (measured cross-section: σ = 3.1 . 10 -13 cm 2 ) for populating high-angular-momentum autoionizing states of barium

  16. Excited-State N2 Dissociation Pathway on Fe-Functionalized Au.

    Science.gov (United States)

    Martirez, John Mark P; Carter, Emily A

    2017-03-29

    Localized surface plasmon resonances (LSPRs) offer the possibility of light-activated chemical catalysis on surfaces of strongly plasmonic metal nanoparticles. This technology relies on lower-barrier bond formation and/or dissociation routes made available through energy transfer following the eventual decay of LSPRs. The coupling between these decay processes and a chemical trajectory (nuclear motion, charge-transfer, intersystem crossing, etc.) dictates the availability of these alternative (possibly lower barrier) excited-state channels. The Haber-Bosch method of NH 3 synthesis from N 2 and H 2 is notoriously energy intensive. This is due to the difficulty of N 2 dissociation despite the overall reaction being thermodynamically favorable at ambient temperatures and pressures. LSPRs may provide means to improve the kinetics of N 2 dissociation via induced resonance electronic excitation. In this work, we calculate, via embedded n-electron valence second-order perturbation theory within the density functional embedding theory, the excited-state potential energy surfaces for dissociation of N 2 on an Fe-doped Au(111) surface. This metal alloy may take advantage simultaneously of the strong LSPR of Au and the catalytic activity of Fe toward N 2 dissociation. We find the ground-state dissociation activation energy to be 4.74 eV/N 2 , with Fe as the active site on the surface. Consecutive resonance energy transfers (RETs) may be accessed due to the availability of many electronically excited states with intermediate energies arising from the metal surface that may couple to states induced by the Fe-dopant and the adsorbate molecule, and crossing between excited states may effectively lower the dissociation barrier to 1.33 eV. Our work illustrates that large energetic barriers, prohibitive toward chemical reaction, may be overcome through multiple RETs facilitating an otherwise difficult chemical process.

  17. Crossover from bound to free states in plasmas

    International Nuclear Information System (INIS)

    Lankin, Alexander V; Norman, Genri E

    2009-01-01

    A self-consistent joint description of free and weakly bound electron states in strongly coupled plasmas is presented. The existence of two problems is emphasized. The first one is a well-known restriction of the number of atomic excited states. Another one is a description of the smooth crossover from bound pair electron-ion excited states to collective excitations of free electrons. The fluctuation approach is developed to study the spectrum domain intermediate between low-lying excited atoms and free electron continuous energy levels. The molecular dynamics method is applied to study the plasma model since the method is able to distinguish all kinds of fluctuations. The electron-ion interaction is described by the temperature-independent cut-off Coulomb potential. The diagnostics of pair electron-ion fluctuations is developed. The concept of pair fluctuations elucidates the smooth vanishing of atomic states near the ionization limit. The approach suggested removes the artificial break of the electron state density at the ionization limit: atomic state density divergent at the negative energy side and free electron state density starting from zero density at the positive energy side

  18. Excited State Structural Dynamics of Carotenoids and Charge Transfer Systems

    International Nuclear Information System (INIS)

    Van Tassle, Aaron Justin

    2006-01-01

    This dissertation describes the development and implementation of a visible/near infrared pump/mid-infrared probe apparatus. Chapter 1 describes the background and motivation of investigating optically induced structural dynamics, paying specific attention to solvation and the excitation selection rules of highly symmetric molecules such as carotenoids. Chapter 2 describes the development and construction of the experimental apparatus used throughout the remainder of this dissertation. Chapter 3 will discuss the investigation of DCM, a laser dye with a fluorescence signal resulting from a charge transfer state. By studying the dynamics of DCM and of its methyl deuterated isotopomer (an otherwise identical molecule), we are able to investigate the origins of the charge transfer state and provide evidence that it is of the controversial twisted intramolecular (TICT) type. Chapter 4 introduces the use of two-photon excitation to the S1 state, combined with one-photon excitation to the S2 state of the carotenoid beta-apo-8'-carotenal. These 2 investigations show evidence for the formation of solitons, previously unobserved in molecular systems and found only in conducting polymers Chapter 5 presents an investigation of the excited state dynamics of peridinin, the carotenoid responsible for the light harvesting of dinoflagellates. This investigation allows for a more detailed understanding of the importance of structural dynamics of carotenoids in light harvesting

  19. Giant dipole resonances built on excited states

    International Nuclear Information System (INIS)

    Snover, K.A.

    1983-01-01

    The properties of giant dipole resonances built on excited nuclear states are reviewed, with emphasis on recent results. Nonstatistical (p,γ) reactions in light nuclei, and statistical complex-particle reactions in light and heavy nuclei are discussed. 27 references

  20. Complex dynamics of an archetypal self-excited SD oscillator driven by moving belt friction

    International Nuclear Information System (INIS)

    Li Zhi-Xin; Cao Qing-Jie; Alain, Léger

    2016-01-01

    We propose an archetypal self-excited system driven by moving belt friction, which is constructed with the smooth and discontinuous (SD) oscillator proposed by the Cao et al. and the classical moving belt. The moving belt friction is modeled as the Coulomb friction to formulate the mathematical model of the proposed self-excited SD oscillator. The equilibrium states of the unperturbed system are obtained to show the complex equilibrium bifurcations. Phase portraits are depicted to present the hyperbolic structure transition, the multiple stick regions, and the friction-induced asymmetry phenomena. The numerical simulations are carried out to demonstrate the friction-induced vibration of multiple stick-slip phenomena and the stick-slip chaos in the perturbed self-excited system. The results presented here provide an opportunity for us to get insight into the mechanism of the complex friction-induced nonlinear dynamics in mechanical engineering and geography. (paper)

  1. Deciphering excited state evolution in halorhodopsin with stimulated emission pumping.

    Science.gov (United States)

    Bismuth, Oshrat; Komm, Pavel; Friedman, Noga; Eliash, Tamar; Sheves, Mordechai; Ruhman, Sanford

    2010-03-04

    The primary photochemical dynamics of Hb. pharaonis Halorhodopsin (pHR) are investigated by femtosecond visible pump-near IR dump-hyperspectral probe spectroscopy. The efficiency of excited state depletion is deduced from transient changes in absorption, recorded with and without stimulated emission pumping (SEP), as a function of the dump delay. The concomitant reduction of photocycle population is assessed by probing the "K" intermediate difference spectrum. Results show that the cross section for stimulating emission is nearly constant throughout the fluorescent state lifetime. Probing "K" demonstrates that dumping produces a proportionate reduction in photocycle yields. We conclude that, despite its nonexponential internal conversion (IC) kinetics, the fluorescent state in pHR constitutes a single intermediate in the photocycle. This contrasts with conclusions drawn from the study of primary events in the related chloride pump from Hb. salinarum (sHR), believed to produce the "K" intermediate from a distinct short-lived subpopulation in the excited state. Our discoveries concerning internal conversion dynamics in pHR are discussed in light of recent expectations for similar excited state dynamics in both proteins.

  2. Coherence, energy and charge transfers in de-excitation pathways of electronic excited state of biomolecules in photosynthesis

    DEFF Research Database (Denmark)

    Bohr, Henrik; Malik, F. Bary

    2013-01-01

    The observed multiple de-excitation pathways of photo-absorbed electronic excited state in the peridinin–chlorophyll complex, involving both energy and charge transfers among its constituents, are analyzed using the bio-Auger (B-A) theory. It is also shown that the usually used F¨orster–Dexter...

  3. First Double Excitation Cross Sections of Helium Measured for 100-keV Proton Impact

    Energy Technology Data Exchange (ETDEWEB)

    Moretto-Capelle, P.; Bordenave-Montesquieu, D.; Bordenave-Montesquieu, A. [Laboratoire Collisions, Agregats, Reactivite, IRSAMC, UMR 5589, CNRS and Universite Paul Sabatier, 31062 Toulouse Cedex (France); Godunov, A.L.; Schipakov, V.A. [Troitsk Institute for Innovation and Fusion Research, Troitsk, Moscow region, 142092 (Russia)

    1997-12-01

    Excitation cross sections of the (2s{sup 2}){sup 1}S, (2p{sup 2}){sup 1}D , and (2s2p){sup 1}P autoionizing states of helium, produced in collisions with 100-keV protons, have been measured for the first time. Using a high resolution electron spectroscopy together with a recently proposed parametrization of autoionizing resonances distorted by Coulomb interaction in the final state makes it possible to extract from electron spectra {ital total cross sections} as well as {ital magnetic sublevel populations.} These new experimental data are briefly compared with out theoretical calculations. {copyright} {ital 1997} {ital The American Physical Society}

  4. Numerical simulations of oscillating soliton stars: Excited states in spherical symmetry and ground state evolutions in 3D

    International Nuclear Information System (INIS)

    Balakrishna, Jayashree; Bondarescu, Ruxandra; Daues, Gregory; Bondarescu, Mihai

    2008-01-01

    Excited state soliton stars are studied numerically for the first time. The stability of spherically symmetric S-branch excited state oscillatons under radial perturbations is investigated using a 1D code. We find that these stars are inherently unstable either migrating to the ground state or collapsing to black holes. Higher excited state configurations are observed to cascade through intermediate excited states during their migration to the ground state. This is similar to excited state boson stars [J. Balakrishna, E. Seidel, and W.-M. Suen, Phys. Rev. D 58, 104004 (1998).]. Ground state oscillatons are then studied in full 3D numerical relativity. Finding the appropriate gauge condition for the dynamic oscillatons is much more challenging than in the case of boson stars. Different slicing conditions are explored, and a customized gauge condition that approximates polar slicing in spherical symmetry is implemented. Comparisons with 1D results and convergence tests are performed. The behavior of these stars under small axisymmetric perturbations is studied and gravitational waveforms are extracted. We find that the gravitational waves damp out on a short time scale, enabling us to obtain the complete waveform. This work is a starting point for the evolution of real scalar field systems with arbitrary symmetries

  5. Energy-Looping Nanoparticles: Harnessing Excited-State Absorption for Deep-Tissue Imaging.

    Science.gov (United States)

    Levy, Elizabeth S; Tajon, Cheryl A; Bischof, Thomas S; Iafrati, Jillian; Fernandez-Bravo, Angel; Garfield, David J; Chamanzar, Maysamreza; Maharbiz, Michel M; Sohal, Vikaas S; Schuck, P James; Cohen, Bruce E; Chan, Emory M

    2016-09-27

    Near infrared (NIR) microscopy enables noninvasive imaging in tissue, particularly in the NIR-II spectral range (1000-1400 nm) where attenuation due to tissue scattering and absorption is minimized. Lanthanide-doped upconverting nanocrystals are promising deep-tissue imaging probes due to their photostable emission in the visible and NIR, but these materials are not efficiently excited at NIR-II wavelengths due to the dearth of lanthanide ground-state absorption transitions in this window. Here, we develop a class of lanthanide-doped imaging probes that harness an energy-looping mechanism that facilitates excitation at NIR-II wavelengths, such as 1064 nm, that are resonant with excited-state absorption transitions but not ground-state absorption. Using computational methods and combinatorial screening, we have identified Tm(3+)-doped NaYF4 nanoparticles as efficient looping systems that emit at 800 nm under continuous-wave excitation at 1064 nm. Using this benign excitation with standard confocal microscopy, energy-looping nanoparticles (ELNPs) are imaged in cultured mammalian cells and through brain tissue without autofluorescence. The 1 mm imaging depths and 2 μm feature sizes are comparable to those demonstrated by state-of-the-art multiphoton techniques, illustrating that ELNPs are a promising class of NIR probes for high-fidelity visualization in cells and tissue.

  6. Spectral sum for the color-Coulomb potential in SU(3) Coulomb gauge lattice Yang-Mills theory

    International Nuclear Information System (INIS)

    Nakagawa, Y.; Nakamura, A.; Saito, T.; Toki, H.

    2010-01-01

    We discuss the essential role of the low-lying eigenmodes of the Faddeev-Popov (FP) ghost operator on the confining color-Coulomb potential using SU(3) quenched lattice simulations in the Coulomb gauge. The color-Coulomb potential is expressed as a spectral sum of the FP ghost operator and has been explored by partially summing the FP eigenmodes. We take into account the Gribov copy effects that have a great impact on the FP eigenvalues and the color-Coulomb potential. We observe that the lowest eigenvalue vanishes in the thermodynamic limit much faster than that in the Landau gauge. The color-Coulomb potential at large distances is governed by the near-zero FP eigenmodes; in particular, the lowest one accounts for a substantial portion of the color-Coulomb string tension comparable to the Wilson string tension.

  7. Statistical density of nuclear excited states

    Directory of Open Access Journals (Sweden)

    V. M. Kolomietz

    2015-10-01

    Full Text Available A semi-classical approximation is applied to the calculations of single-particle and statistical level densities in excited nuclei. Landau's conception of quasi-particles with the nucleon effective mass m* < m is used. The approach provides the correct description of the continuum contribution to the level density for realistic finite-depth potentials. It is shown that the continuum states does not affect significantly the thermodynamic calculations for sufficiently small temperatures T ≤ 1 MeV but reduce strongly the results for the excitation energy at high temperatures. By use of standard Woods - Saxon potential and nucleon effective mass m* = 0.7m the A-dependency of the statistical level density parameter K was evaluated in a good qualitative agreement with experimental data.

  8. Coulomb potentials between spherical heavy ions

    International Nuclear Information System (INIS)

    Iwe, H.

    1982-01-01

    The Coulomb interaction between spherical nuclei having arbitrary radial nuclear charge distributions is calculated. All these realistic Coulomb potentials are given in terms of analytical expressions and are available for immediate application. So in no case a numerical computation of the Coulomb integral is required. The parameters of the charge distributions are taken from electron scattering analysis. The Coulomb self-energies of the charge distributions used are also calculated analytically in a closed form. For a number of nucleus-nucleus pairs, the Coulomb potentials derived from realistic charge distributions are compared with those normally used in various nucleus-nucleus optical model calculations. In this connection a detailed discussion of the problem how to choose consistently Coulomb parameters for different approximations is given. (orig.)

  9. Interplay between singlet and triplet excited states in a conformationally locked donor–acceptor dyad

    KAUST Repository

    Filatov, Mikhail A.

    2015-10-13

    The synthesis and photophysical characterization of a palladium(II) porphyrin – anthracene dyad bridged via short and conformationally rigid bicyclo[2.2.2]octadiene spacer were achieved. A spectroscopic investigation of the prepared molecule in solution has been undertaken to study electronic energy transfer in excited singlet and triplet states between the anthracene and porphyrin units. By using steady-state and time-resolved photoluminescence spectroscopy it was shown that excitation of the singlet excited state of the anthracene leads to energy transfer to the lower-lying singlet state of porphyrin. Alternatively, excitation of the porphyrin followed by intersystem crossing to the triplet state leads to very fast energy transfer to the triplet state of anthracene. The rate of this energy transfer has been determined by transient absorption spectroscopy. Comparative studies of the dynamics of triplet excited states of the dyad and reference palladium octaethylporphyrin (PdOEP) have been performed.

  10. Interplay between singlet and triplet excited states in a conformationally locked donor–acceptor dyad

    KAUST Repository

    Filatov, Mikhail A.; Etzold, Fabian; Gehrig, Dominik; Laquai, Fré dé ric; Busko, Dmitri; Landfester, Katharina; Baluschev, Stanislav

    2015-01-01

    The synthesis and photophysical characterization of a palladium(II) porphyrin – anthracene dyad bridged via short and conformationally rigid bicyclo[2.2.2]octadiene spacer were achieved. A spectroscopic investigation of the prepared molecule in solution has been undertaken to study electronic energy transfer in excited singlet and triplet states between the anthracene and porphyrin units. By using steady-state and time-resolved photoluminescence spectroscopy it was shown that excitation of the singlet excited state of the anthracene leads to energy transfer to the lower-lying singlet state of porphyrin. Alternatively, excitation of the porphyrin followed by intersystem crossing to the triplet state leads to very fast energy transfer to the triplet state of anthracene. The rate of this energy transfer has been determined by transient absorption spectroscopy. Comparative studies of the dynamics of triplet excited states of the dyad and reference palladium octaethylporphyrin (PdOEP) have been performed.

  11. Excited-state formation as H+ and He+ ions scatter from metal surfaces

    International Nuclear Information System (INIS)

    Baird, W.E.; Zivitz, M.; Thomas, E.W.

    1975-01-01

    Impact of 10-to30KeV H + or He + ions on polycrystalline metal surfaces causes some projectiles to be backscattered in a neutral excited state. These projectiles subsequently radiatively decay, emitting Doppler-broadened spectral lines. By analysis of the spectral shape of these lines, we are able to determine the probability of radiationless deexcitation of the excited backscattered atoms. Quantitative measurements of spectral intensity indicate that less than 1% of all projectiles are backscattered in an excited state. The relative variation of total spectral line intensity with angle of projectile incidence and with projectile primary energy has been successfully predicted using a model which assumes that the probability for excited-state formation is independent of the scattered projectile's energy and direction. The variation in total spectral line intensity with target atomic number is predicted, and the sputtering and excitation of Al under He + impact is briefly examined

  12. Di-lepton yield from the decay of excited 28Si states

    International Nuclear Information System (INIS)

    Bacelar, J.C.; Buda, A.; Balanda, A.; Krasznahorkay, A.; Ploeg, H. van der; Sujkowski, Z.; Woude, A. van der

    1994-01-01

    The first dilepton yield measurements from excited nuclear states obtained with a new Positron-Electron Pair Spectroscopic Instrument (PEPSI) are reported. Nuclear states in 28 Si, with an initial excitation energy E * =50 MeV, were populated via the isospin T=0 reaction 4 He+ 24 Mg and the mixed-isospin 3 He+ 25 Mg reaction. In both reactions the dilepton (e + e - ) and photon decay yields were measured concurrently. An excess of counts in the e + e - spectrum, over the converted photon yield, is observed in the energy region above 15 MeV. An analyses is discussed whereby the observed excess counts are assumed to represent the isoscalar E0 strength in excited nuclear states. (orig.)

  13. Excited-state Raman spectroscopy with and without actinic excitation: S{sub 1} Raman spectra of trans-azobenzene

    Energy Technology Data Exchange (ETDEWEB)

    Dobryakov, A. L.; Quick, M.; Ioffe, I. N.; Granovsky, A. A.; Ernsting, N. P.; Kovalenko, S. A. [Department of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Str. 2, D-12489 Berlin (Germany)

    2014-05-14

    We show that femtosecond stimulated Raman spectroscopy can record excited-state spectra in the absence of actinic excitation, if the Raman pump is in resonance with an electronic transition. The approach is illustrated by recording S{sub 1} and S{sub 0} spectra of trans-azobenzene in n-hexane. The S{sub 1} spectra were also measured conventionally, upon nπ* (S{sub 0} → S{sub 1}) actinic excitation. The results are discussed and compared to earlier reports.

  14. Sensitivity of (α,α') cross sections to excited-state quadrupole moments

    International Nuclear Information System (INIS)

    Baker, F.T.; Scott, A.; Ronningen, R.M.; Hamilton, J.H.; Kruse, T.H.; Suchannek, R.; Savin, W.

    1977-01-01

    Inelastic α particle scattering at 21 and 24 MeV has been used to estimate the electric quadrupole moment of the second 2 + state in 180 Hf. Sensitivity to the assumed quadrupole moment is due almost entirely to reorientation via the nuclear force. Results suggest that the technique may be a useful method of estimating excited state quadrupole moments, particularly for states with high excitation energies or with J greater than 2

  15. Coulomb oscillations in three-layer graphene nanostructures

    International Nuclear Information System (INIS)

    Guettinger, J; Stampfer, C; Molitor, F; Graf, D; Ihn, T; Ensslin, K

    2008-01-01

    We present transport measurements on a tunable three-layer graphene single electron transistor (SET). The device consists of an etched three-layer graphene flake with two narrow constrictions separating the island from source and drain contacts. Three lateral graphene gates are used to electrostatically tune the device. An individual three-layer graphene constriction has been investigated separately showing a transport gap near the charge neutrality point. The graphene tunneling barriers show a strongly nonmonotonic coupling as a function of gate voltage indicating the presence of localized states in the constrictions. We show Coulomb oscillations and Coulomb diamond measurements proving the functionality of the graphene SET. A charging energy of ∼0.6 meV is extracted.

  16. Three-body continuum states on a Lagrange mesh

    International Nuclear Information System (INIS)

    Descouvemont, P.; Tursunov, E.; Baye, D.

    2006-01-01

    Three-body continuum states are investigated with the hyperspherical method on a Lagrange mesh. The R-matrix theory is used to treat the asymptotic behaviour of scattering wave functions. The formalism is developed for neutral as well as for charged systems. We point out some specificities of continuum states in the hyperspherical method. The collision matrix can be determined with a good accuracy by using propagation techniques. The method is applied to the 6 He (=α+n+n) and 6 Be (=α+p+p) systems, as well as to 14 Be (=Be12+n+n). For 6 He, we essentially recover results of the literature. Application to 14 Be suggests the existence of an excited 2 + state below threshold. The calculated B(E2) value should make this state observable with Coulomb excitation experiments

  17. A Coulomb-Like Off-Shell T-Matrix with the Correct Coulomb Phase Shift

    International Nuclear Information System (INIS)

    Oryu, Shinsho; Watanabe, Takashi; Hiratsuka, Yasuhisa; Togawa, Yoshio

    2017-01-01

    We confirm the reliability of the well-known Coulomb renormalization method (CRM). It is found that the CRM is only available for a very-long-range screened Coulomb potential (SCP). However, such an SCP calculation in momentum space is considerably difficult because of the cancellation of significant digits. In contrast to the CRM, we propose a new method by using an on-shell equivalent SCP and the rest term. The two-potential theory with r-space is introduced, which defines fully the off-shell Coulomb amplitude. (author)

  18. Generalized second-order Coulomb phase shift functions

    International Nuclear Information System (INIS)

    Rosendorff, S.

    1982-01-01

    Some specific properties and the evaluation of the generalized second-order Coulomb phase shift functions (two-dimensional integrals of four spherical cylinder functions) are discussed. The dependence on the three momenta k 1 ,k-bar,k 2 , corresponding to the final, intermediate, and initial states is illustrated

  19. Coulomb plus strong interaction bound states - momentum space numerical solutions

    International Nuclear Information System (INIS)

    Heddle, D.P.; Tabakin, F.

    1985-01-01

    The levels and widths of hadronic atoms are calculated in momentum space using an inverse algorithm for the eigenvalue problem. The Coulomb singularity is handled by the Lande substraction method. Relativistic, nonlocal, complex hadron-nucleus interactions are incorporated as well as vacuum polarization and finite size effects. Coordinate space wavefunctions are obtained by employing a Fourier Bessel transformation. (orig.)

  20. Particle hole excitations coupled to complex states in heavy-ion collisions

    International Nuclear Information System (INIS)

    Jolos, R.V.; Schmidt, R.

    1982-01-01

    The excitation of uncorrelated 1p-1h states in one nucleus due to the action of the time-dependent mean field of the other nucleus was studied earlier. No statistical assumptions or average procedures were made. Such a mechanism can be responsible for an appreciable excitation of the two nuclei during the short approach phase of the reaction (E* approximately> 100 MeV). The reversibility of the equations of motion leads to a deexcitation of the initially stored excitation energy into that of the relative motion for later times. This feedback behaviour of the internal excitation energy which results in particular to the deexcitation of high energetic 1p-1h pairs is probably not realistic due to the coupling of this states to more complex states with high density. It is studied the influence of this coupling due to the residual interaction between the nucleons on the dynamics of two colliding heavy ions

  1. Observation of excited state charge transfer with fs/ps-CARS

    International Nuclear Information System (INIS)

    Blom, Alex Jason

    2009-01-01

    Excited state charge transfer processes are studied using the fs/ps-CARS probe technique. This probe allows for multiplexed detection of Raman active vibrational modes. Systems studied include Michler's Ketone, Coumarin 120, 4-dimethylamino-4(prime)-nitrostilbene, and several others. The vibrational spectrum of the para di-substituted benzophenone Michler's Ketone in the first excited singlet state is studied for the first time. It is found that there are several vibrational modes indicative of structural changes of the excited molecule. A combined experimental and theoretical approach is used to study the simplest 7-amino-4-methylcoumarin, Coumarin 120. Vibrations observed in FTIR and spontaneous Raman spectra are assigned using density functional calculations and a continuum solvation model is used to predict how observed modes are affected upon inclusion of a solvent. The low frequency modes of the excited state charge transfer species 4-dimethylamino-4(prime)-nitrostilbene are studied in acetonitrile. Results are compared to previous work on this molecule in the fingerprint region. Finally, several partially completed projects and their implications are discussed. These include the two photon absorption of Coumarin 120, nanoconfinement in cyclodextrin cavities and sensitization of titania nanoparticles

  2. Observation of excited state charge transfer with fs/ps-CARS

    Energy Technology Data Exchange (ETDEWEB)

    Blom, Alex Jason [Iowa State Univ., Ames, IA (United States)

    2009-01-01

    Excited state charge transfer processes are studied using the fs/ps-CARS probe technique. This probe allows for multiplexed detection of Raman active vibrational modes. Systems studied include Michler's Ketone, Coumarin 120, 4-dimethylamino-4'-nitrostilbene, and several others. The vibrational spectrum of the para di-substituted benzophenone Michler's Ketone in the first excited singlet state is studied for the first time. It is found that there are several vibrational modes indicative of structural changes of the excited molecule. A combined experimental and theoretical approach is used to study the simplest 7-amino-4-methylcoumarin, Coumarin 120. Vibrations observed in FTIR and spontaneous Raman spectra are assigned using density functional calculations and a continuum solvation model is used to predict how observed modes are affected upon inclusion of a solvent. The low frequency modes of the excited state charge transfer species 4-dimethylamino-4{prime}-nitrostilbene are studied in acetonitrile. Results are compared to previous work on this molecule in the fingerprint region. Finally, several partially completed projects and their implications are discussed. These include the two photon absorption of Coumarin 120, nanoconfinement in cyclodextrin cavities and sensitization of titania nanoparticles.

  3. Energies and lifetimes of excited states in copperlike Kr VIII

    International Nuclear Information System (INIS)

    Livingston, A.E.; Curtis, L.J.; Schectman, R.M.; Berry, H.G.

    1980-01-01

    The spectrum of Kr VIII has been observed between 180 and 2000 A by using foil excitation of 2.5--3.5-MeV krypton ions. Twenty new transitions have been classified and eleven new excited-state energies have been determined within the n=4 --7 shells. The ionization potential is derived to be 1 015 800 +- 200 cm -1 . The excited-state energies and fine structures are compared with recent relativistic Hartree-Fock calculations. The 4p-state lifetime has been measured by performing a simultaneous analysis of decay data for the 4p level and for its dominant cascade-repopulating levels. The 4p lifetime is found to be 30% shorter than previously measured values and is in excellent agreement with the result of a recent multiconfiguration Hartree-Fock calculation. The source of the discrepancy between this result and earlier measurements is discussed

  4. Coulomb excitation of $^{94,96}$Kr beam Deformation in the neutron-rich krypton isotopes

    CERN Multimedia

    Hass, M; Cederkall, J A; Di julio, D D; Zamfir, N - V; Srebrny, J; Wadsworth, R; Siem, S; Marginean, R; Iwanicki, J S

    Recently the energy of the 2$_{1}^{+}$ state in the N=60 $^{96}$Kr nucleus was determinated to be 241 keV. This was the first experimental observation of an excited state in this highly exotic nucleus. The 2$_{1}^{+}$ state in $^{94}$Kr is located at 665.5 keV, i.e. E(2$_{1}^{+}$) drops by more than 400 keV at N=60. This lowering of the 2$_{1}^{+}$ energy indicates a sharp shape transition behavior which is somewhat similar to that discovered in the Sr and Zr isotopic chains at N=60. The deformation expected for the 2$_{1}^{+}$ state of $^{96}$Kr, as resulting from the E(2$_{1}^{+}$) energy based on the semi-empirical relation of Raman et al. is $\\beta_{2}$ = 0.31, which is, however, considerably smaller than that for Sr and Zr ($\\geq$0.40). The sudden decrease of E(2$_{1}^{+}$) from N=50 to N=60 does not fully agree with the more gradual change of deformation deduced from laser spectroscopy measurements of mean square charge radii, although for $^{96}$Kr, in particular, these are consistent with a $\\beta_{2}...

  5. Cross sections for the vibrational excitation of the H2 X 1Σ+g(v) levels generated by electron collisional excitation of the higher singlet states

    International Nuclear Information System (INIS)

    Hiskes, J.R.

    1991-01-01

    The excitation cross sections, σ(v,v double-prime), for an H 2 molecule initially in any one of the 15 vibrational levels, v belonging to the ground electronic state and excited to a final vibrational level, v double-prime are evaluated for direct excitations via all members of the excited electronic singlet spectrum. Account is taken of predissociation, autoionization, and radiative decay of the excited electronic spectrum that leads to a final population distribution for the ground electronic state, X 1 Σ + g (v double-prime). For v=0, account is taken explicitly of transitions via the B, C, B', and D electronic states in evaluating the cross sections. The additional contribution of excitations via all Rydberg states lying above the D state enhances these cross sections by approximately 10%. For v>0, cross sections are evaluated taking explicit account of transitions through the B and C states; higher singlet excitations enhance these values by 25%. The choice of the reference total cross sections remains a subjective one, causing the values calculated here to have a possible uncertainty of +20% -30% . For excitations occurring within a hydrogen discharge, collisional excitation-ionization events among the intermediate singlet states will effectively quench the v, v double-prime excitation process for discharge densities in excess of the range 10 15 --10 16 electrons/cm -3

  6. Watson-Crick base pairing controls excited-state decay in natural DNA.

    Science.gov (United States)

    Bucher, Dominik B; Schlueter, Alexander; Carell, Thomas; Zinth, Wolfgang

    2014-10-13

    Excited-state dynamics are essential to understanding the formation of DNA lesions induced by UV light. By using femtosecond IR spectroscopy, it was possible to determine the lifetimes of the excited states of all four bases in the double-stranded environment of natural DNA. After UV excitation of the DNA duplex, we detected a concerted decay of base pairs connected by Watson-Crick hydrogen bonds. A comparison of single- and double-stranded DNA showed that the reactive charge-transfer states formed in the single strands are suppressed by base pairing in the duplex. The strong influence of the Watson-Crick hydrogen bonds indicates that proton transfer opens an efficient decay path in the duplex that prohibits the formation or reduces the lifetime of reactive charge-transfer states. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Stability of Dirac Liquids with Strong Coulomb Interaction.

    Science.gov (United States)

    Tupitsyn, Igor S; Prokof'ev, Nikolay V

    2017-01-13

    We develop and apply the diagrammatic Monte Carlo technique to address the problem of the stability of the Dirac liquid state (in a graphene-type system) against the strong long-range part of the Coulomb interaction. So far, all attempts to deal with this problem in the field-theoretical framework were limited either to perturbative or random phase approximation and functional renormalization group treatments, with diametrically opposite conclusions. Our calculations aim at the approximation-free solution with controlled accuracy by computing vertex corrections from higher-order skeleton diagrams and establishing the renormalization group flow of the effective Coulomb coupling constant. We unambiguously show that with increasing the system size L (up to ln(L)∼40), the coupling constant always flows towards zero; i.e., the two-dimensional Dirac liquid is an asymptotically free T=0 state with divergent Fermi velocity.

  8. Ioniclike energy structure of neutral core-excited states in free Kr clusters

    International Nuclear Information System (INIS)

    Peredkov, S.; Sorensen, S.L.; Kivimaeki, A.; Schulz, J.; Maartensson, N.; Oehrwall, G.; Lundwall, M.; Rander, T.; Lindblad, A.; Bergersen, H.; Svensson, S.; Bjoerneholm, O.; Tchaplyguine, M.

    2005-01-01

    The development of electronic states in krypton clusters is investigated by high-resolution core-level electron spectroscopy. The energy ordering of bulk versus surface 3d -1 np(n>5) core-excited states in neutral clusters is demonstrated to be reversed to the 3d -1 5p level situation. The cluster 3d -1 6p,7p states are proven to be at a lower energy than the corresponding atomic levels. These findings reveal the ioniclike energy structure of the neutral cluster core-excited levels. The phenomenon is explained by a spatial spread of the excited orbitals over the cluster lattice

  9. Clustered chimera states in systems of type-I excitability

    International Nuclear Information System (INIS)

    Vüllings, Andrea; Omelchenko, Iryna; Hövel, Philipp; Hizanidis, Johanne

    2014-01-01

    The chimera state is a fascinating phenomenon of coexisting synchronized and desynchronized behaviour that was discovered in networks of nonlocally coupled identical phase oscillators over ten years ago. Since then, chimeras have been found in numerous theoretical and experimental studies and more recently in models of neuronal dynamics as well. In this work, we consider a generic model for a saddle-node bifurcation on a limit cycle representative of neural excitability type I. We obtain chimera states with multiple coherent regions (clustered chimeras/multi-chimeras) depending on the distance from the excitability threshold, the range of nonlocal coupling and the coupling strength. A detailed stability diagram for these chimera states and other interesting coexisting patterns (like traveling waves) is presented. (paper)

  10. The triplet excited state of bilirubin

    International Nuclear Information System (INIS)

    Land, E.J.

    1976-01-01

    Pulse radiolysis of benzene solutions of 40 μM bilirubin alone or with 0.1 M biphenyl has yielded evidence for the formation of the triplet excited state of bilirubin. Measurements were made of a number of properties, including the absorption spectrum (lambdasub(max)500nm), lifetime 9μs), extinction coefficient (8800 M -1 cm -1 ), energy level (approximately 150 kJ mol -1 ) and the rate of quenching by oxygen (rate constant, 8.2 x 10 8 M -1 s -1 ). An upper limit of 0.1 has also been obtained for the singlet to triplet crossover efficiency of bilirubin following excitation by 353 nm radiation. Consideration is given to the relevance of these data to the mechanism of bilirubin photo-destruction, both in vivo and in vitro. (U.K.)

  11. Electron impact excitation of 1'S-2'S transition in helium

    International Nuclear Information System (INIS)

    Mohanty, J.P.; Singh, C.S.

    1989-01-01

    The modified variable-charge Coulomb-projected Born approximation is applied to electron impact excitation of 1 1 S-2 1 S transition in helium. The results are compared with other theoretical and experimental results. (author). 30 refs., 4 figs

  12. Technique for description of nonrotational excited states in a semiphenomenological nuclear theory

    International Nuclear Information System (INIS)

    Krutov, V.A.

    1985-01-01

    A non-standard technique for microscopic description of excited nonrotational states is considered; it is suitable for inseparable force application. Besides, an additional binding operator, mixing quasi-particle excitations and E1-resonance states, is considered. Instead of the standard technique of state ''collectivization'' of the random phase approximation type it is used the so-called ''method of bound amplitudes''

  13. Non-orthogonal configuration interaction for the calculation of multielectron excited states

    Energy Technology Data Exchange (ETDEWEB)

    Sundstrom, Eric J., E-mail: eric.jon.sundstrom@berkeley.edu; Head-Gordon, Martin [Department of Chemistry, University of California Berkeley, Berkeley, California 94720, USA and Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

    2014-03-21

    We apply Non-orthogonal Configuration Interaction (NOCI) to molecular systems where multielectron excitations, in this case double excitations, play a substantial role: the linear polyenes and β-carotene. We demonstrate that NOCI when applied to systems with extended conjugation, provides a qualitatively correct wavefunction at a fraction of the cost of many other multireference treatments. We also present a new extension to this method allowing for purification of higher-order spin states by utilizing Generalized Hartree-Fock Slater determinants and the details for computing 〈S{sup 2}〉 for the ground and excited states.

  14. Excited State s-cis Rotamers Produced by Extreme Red Edge Excitation of all-trans-1,4-Diphenyl-1,3-butadiene

    DEFF Research Database (Denmark)

    Wallace-Williams, Stacie E.; Møller, Søren; Goldbeck, Robert A.

    1993-01-01

    with the wavelength independence observed for the excited singlet-state absorption and fluorescence emission spectra of 1,5-diphenyl-2,3,4,6,7,8- hexahydronaphthalene and for the fluorescence emission spectra of 1,4diphenyl-1,3-cyclopentadiene, s-trans and s-cis structural analogs of DPB, respectively. The spectral...... changes in DPB can be explained in terms of an excitation wavelength-dependent production of s-cis and s-trans rotamer populations in the excited state. The DPB fluorescence emission spectrum was resolved into s-cis and s-trans components. The vibronic structure of the s-cis fluorescence spectrum...... is similar to that of s-trans, but the band origin is red-shifted and there is a slightly larger amplitude on the red edge. The excited-state absorption spectrum of s-cis DPB appears to be red-shifted relative to that of s-trans DPB as well....

  15. Study of highly excited high spin states via the (HI, α) reaction

    International Nuclear Information System (INIS)

    Kubono, S.

    1982-01-01

    Three subjects are discussed in this paper. 1) The mechanism of (HI, α) reactions is briefly studied. 2) Possible excitation of molecular resonance states of 12 C- 12 C in 24 Mg through the 12 C( 16 O, α) 24 Mg reaction were investigated. A precise measurement of the level widths in 24 Mg did not support the previous report that the molecular states seen in 12 C + 12 C scattering had been excited in the transfer reaction 12 C( 16 O, α) 24 Mg. 3) Highly excited states in 28 Si, which have a large parentage of 12 C- 16 O, were also studied via the 12 C( 20 Ne, α) 28 Si reaction. An angular correlation measurement revealed the lowest 8 + and 10 + states at 14.00 and 15.97 MeV, respectively, which were selectively excited in the 12 C( 20 Ne, α) reaction. These results suggest a possible new band in 28 Si. (author)

  16. Coherent excitation of a single atom to a Rydberg state

    DEFF Research Database (Denmark)

    Miroshnychenko, Yevhen; Gaëtan, Alpha; Evellin, Charles

    2010-01-01

    We present the coherent excitation of a single Rubidium atom to the Rydberg state 58d3/2 using a two-photon transition. The experimental setup is described in detail, as are experimental techniques and procedures. The coherence of the excitation is revealed by observing Rabi oscillations between...

  17. Some studies on the formation of excited states of aromatic solutes in hydrocarbons and other solvents

    Energy Technology Data Exchange (ETDEWEB)

    Salmon, G A [Leeds Univ. (UK). Cookridge High Energy Radiation Research Centre

    1976-01-01

    This paper reviews the work of the author and his co-workers on the radiation-induced formation of excited states of aromatic compounds in solution. The experimental methods used are surveyed and in particular the method of measuring the yields of triplet and singlet excited states of the solute are described. The problems discussed are: (1) the effect of solvent on the yields of excited states, (2) formation of excited states in cyclohexane and other alicyclic hydrocarbons, (3) the formation of excited states in benzene and (4) the identification of T-T absorption spectra.

  18. Excitation of spin-1 states in 166168170Er using bremsstrahlung

    International Nuclear Information System (INIS)

    Metzger, F.R.

    1976-01-01

    Some 40 states in 166 , 168 , 170 Er, most of them previously unknown, have been excited using bremsstrahlung with < or =4.2 MeV endpoint energy. For all but three of these levels, the angular distribution of the resonantly scattered radiation favors the assignment of spin 1. For some of the strongly excited levels, linear polarization measurements have been performed. They indicate that these levels have positive parity. The branching ratios further characterize them as K=1 excitations

  19. Excited-state dynamics of the medicinal pigment curcumin in a hydrogel.

    Science.gov (United States)

    Harada, Takaaki; Lincoln, Stephen F; Kee, Tak W

    2016-10-12

    Curcumin is a yellow polyphenol with multiple medicinal effects. These effects, however, are limited due to its poor aqueous stability and solubility. A hydrogel of 3% octadecyl randomly substituted polyacrylate (PAAC18) has been shown to provide high aqueous stability for curcumin under physiological conditions, offering a route for photodynamic therapy. In this study, the excited-state photophysics of curcumin in the PAAC18 hydrogel is investigated using a combination of femtosecond transient absorption and fluorescence upconversion spectroscopy. The transient absorption results reveal a multiexponential decay in the excited-state kinetics with fast (1 ps & 15 ps) and slow (110 ps & ≈5 ns) components. The fast decay component exhibits a deuterium isotope effect with D 2 O in the hydrogel, indicating that the 15 ps decay component is attributable to excited-state intramolecular hydrogen atom transfer of curcumin in the PAAC18 hydrogel. In addition, solvent reorganisation of excited-state curcumin is investigated using multiwavelength femtosecond fluorescence upconversion spectroscopy. The results show that the dominant solvation response (τ = 0.08 ps) is a fast inertial motion owing to the presence of bulk-like water in the vicinity of the hydrophobic octadecyl substituents of the PAAC18 hydrogel. The results also show an additional response with longer time constants of 1 and 6 ps, which is attributable to translational diffusion of confined water molecules in the three-dimensional, cross-linking network of the octadecyl substituents of PAAC18. Overall, we show that excited-state intramolecular hydrogen atom transfer and solvent reorganisation are major photophysical events for curcumin in the PAAC18 hydrogel.

  20. Rearrangements in ground and excited states

    CERN Document Server

    de Mayo, Paul

    1980-01-01

    Rearrangements in Ground and Excited States, Volume 2 covers essays on the theoretical approach of rearrangements; the rearrangements involving boron; and the molecular rearrangements of organosilicon compounds. The book also includes essays on the polytopal rearrangement at phosphorus; the rearrangement in coordination complexes; and the reversible thermal intramolecular rearrangements of metal carbonyls. Chemists and people involved in the study of rearrangements will find the book invaluable.

  1. Tracking excited-state charge and spin dynamics in iron coordination complexes

    DEFF Research Database (Denmark)

    Zhang, Wenkai; Alonso-Mori, Roberto; Bergmann, Uwe

    2014-01-01

    to spin state, can elucidate the spin crossover dynamics of [Fe(2,2'-bipyridine)(3)](2+) on photoinduced metal-to-ligand charge transfer excitation. We are able to track the charge and spin dynamics, and establish the critical role of intermediate spin states in the crossover mechanism. We anticipate......Crucial to many light-driven processes in transition metal complexes is the absorption and dissipation of energy by 3d electrons(1-4). But a detailed understanding of such non-equilibrium excited-state dynamics and their interplay with structural changes is challenging: a multitude of excited...... states and possible transitions result in phenomena too complex to unravel when faced with the indirect sensitivity of optical spectroscopy to spin dynamics(5) and the flux limitations of ultrafast X-ray sources(6,7). Such a situation exists for archetypal poly-pyridyl iron complexes, such as [Fe(2...

  2. Linear-scaling quantum mechanical methods for excited states.

    Science.gov (United States)

    Yam, ChiYung; Zhang, Qing; Wang, Fan; Chen, GuanHua

    2012-05-21

    The poor scaling of many existing quantum mechanical methods with respect to the system size hinders their applications to large systems. In this tutorial review, we focus on latest research on linear-scaling or O(N) quantum mechanical methods for excited states. Based on the locality of quantum mechanical systems, O(N) quantum mechanical methods for excited states are comprised of two categories, the time-domain and frequency-domain methods. The former solves the dynamics of the electronic systems in real time while the latter involves direct evaluation of electronic response in the frequency-domain. The localized density matrix (LDM) method is the first and most mature linear-scaling quantum mechanical method for excited states. It has been implemented in time- and frequency-domains. The O(N) time-domain methods also include the approach that solves the time-dependent Kohn-Sham (TDKS) equation using the non-orthogonal localized molecular orbitals (NOLMOs). Besides the frequency-domain LDM method, other O(N) frequency-domain methods have been proposed and implemented at the first-principles level. Except one-dimensional or quasi-one-dimensional systems, the O(N) frequency-domain methods are often not applicable to resonant responses because of the convergence problem. For linear response, the most efficient O(N) first-principles method is found to be the LDM method with Chebyshev expansion for time integration. For off-resonant response (including nonlinear properties) at a specific frequency, the frequency-domain methods with iterative solvers are quite efficient and thus practical. For nonlinear response, both on-resonance and off-resonance, the time-domain methods can be used, however, as the time-domain first-principles methods are quite expensive, time-domain O(N) semi-empirical methods are often the practical choice. Compared to the O(N) frequency-domain methods, the O(N) time-domain methods for excited states are much more mature and numerically stable, and

  3. Coulomb correction calculations of pp Bremsstrahlung

    International Nuclear Information System (INIS)

    Katsogiannis, A.; Amos, K.; Jetter, M.; von Geramb, H.V.

    1994-01-01

    The effects of the Coulomb interaction upon the photon cross section and analyzing power from pp Bremsstrahlung have been studied in detail. Off-shell properties of the Coulomb T matrices have been considered but the associated, Coulomb modified, hadronic T matrices are important elements in any analyses of low energy, forward proton scattering data. At the lowest energy considered (5 MeV), the full calculations gave cross sections that were half the size of those found without Coulomb effects or with a simple model approximation to them. With increasing energy, the cross sections varied to those characteristic of magnetic interaction dominance and the specific differences due to Coulomb effects diminished. 47 refs., 7 figs

  4. Two-electron excitation in slow ion-atom collisions: Excitation mechanisms and interferences among autoionizing states

    International Nuclear Information System (INIS)

    Kimura, M.; Rice Univ., Houston, TX

    1990-01-01

    The two-electron capture or excitation process resulting from collisions of H + and O 6+ ions with He atoms in the energy range from 0.5 keV/amu to 5 keV/amu is studied within a molecular representation. The collision dynamics for formation of doubly excited O 4+ ions and He** atoms and their (n ell, n'ell ') populations are analyzed in conjunction with electron correlations. Autoionizing states thus formed decay through the Auger process. An experimental study of an ejected electron energy spectrum shows ample structures in addition to two characteristic peaks that are identified by atomic and molecular autoionizations. These structures are attributable to various interferences among electronic states and trajectories. We examine the dominant sources of the interferences. 12 refs., 5 figs

  5. Using narrowband excitation to confirm that the S∗ state in carotenoids is not a vibrationally-excited ground state species

    Science.gov (United States)

    Jailaubekov, Askat E.; Song, Sang-Hun; Vengris, Mikas; Cogdell, Richard J.; Larsen, Delmar S.

    2010-02-01

    The hypothesis that S∗ is a vibrationally-excited ground-state population is tested and discarded for two carotenoid samples: β-carotene in solution and rhodopin glucoside embedded in the light harvesting 2 protein from Rhodopseudomonas acidophila. By demonstrating that the transient absorption signals measured in both systems that are induced by broadband (1000 cm -1) and narrowband (50 cm -1) excitation pulses are near identical and hence bandwidth independent, the impulsive stimulated Raman scattering mechanism proposed as the primary source for S∗ generation is discarded. To support this conclusion, previously published multi-pulse pump-dump-probe signals [17] are revisited to discard secondary mechanisms for S∗ formation.

  6. Unified approach to probing Coulomb effects in tunnel ionization for any ellipticity of laser light.

    Science.gov (United States)

    Landsman, A S; Hofmann, C; Pfeiffer, A N; Cirelli, C; Keller, U

    2013-12-27

    We present experimental data that show significant deviations from theoretical predictions for the location of the center of the electron momenta distribution at low values of ellipticity ε of laser light. We show that these deviations are caused by significant Coulomb focusing along the minor axis of polarization, something that is normally neglected in the analysis of electron dynamics, even in cases where the Coulomb correction is otherwise taken into account. By investigating ellipticity-resolved electron momenta distributions in the plane of polarization, we show that Coulomb focusing predominates at lower values of ellipticity of laser light, while Coulomb asymmetry becomes important at higher values, showing that these two complementary phenomena can be used to probe long-range Coulomb interaction at all polarizations of laser light. Our results suggest that both the breakdown of Coulomb focusing and the onset of Coulomb asymmetry are linked to the disappearance of Rydberg states with increasing ellipticity.

  7. Self-energy correction to the hyperfine splitting for excited states

    International Nuclear Information System (INIS)

    Wundt, B. J.; Jentschura, U. D.

    2011-01-01

    The self-energy corrections to the hyperfine splitting is evaluated for higher excited states in hydrogenlike ions using an expansion in the binding parameter Zα, where Z is the nuclear-charge number and α is the fine-structure constant. We present analytic results for D, F, and G states, and for a number of highly excited Rydberg states, with principal quantum numbers in the range 13≤n≤16, and orbital angular momenta l=n-2 and l=n-1. A closed-form analytic expression is derived for the contribution of high-energy photons, valid for any state with l≥2 and arbitrary n, l, and total angular momentum j. The low-energy contributions are written in the form of generalized Bethe logarithms and evaluated for selected states.

  8. Mechanism for the Excited-State Multiple Proton Transfer Process of Dihydroxyanthraquinone Chromophores.

    Science.gov (United States)

    Zhou, Qiao; Du, Can; Yang, Li; Zhao, Meiyu; Dai, Yumei; Song, Peng

    2017-06-22

    The single and dual cooperated proton transfer dynamic process in the excited state of 1,5-dihydroxyanthraquinone (1,5-DHAQ) was theoretically investigated, taking solvent effects (ethanol) into account. The absorption and fluorescence spectra were simulated, and dual fluorescence exhibited, which is consistent with previous experiments. Analysis of the calculated IR and Raman vibration spectra reveals that the intramolecular hydrogen bonding interactions (O 20 -H 21 ···O 24 and O 22 -H 23 ···O 25 ) are strengthened following the excited proton transfer process. Finally, by constructing the potential energy surfaces of the ground state, first excited singlet state, and triplet state, the mechanism of the intramolecular proton transfer of 1,5-DHAQ can be revealed.

  9. Equations of state for self-excited MHD generator studies

    Energy Technology Data Exchange (ETDEWEB)

    Rogers, F.J.; Ross, M.; Haggin, G.L.; Wong, L.K.

    1980-02-26

    We have constructed a state-of-the-art equation of state (EOS) for argon covering the temperature density range attainable by currently proposed self-excited MHD generators. The EOS for conditions in the flow channel was obtained primarily by a non-ideal plasma code (ACTEX) that is based on a many body activity expansion. For conditions in the driver chamber the EOS was primarily obtained from a fluid code (HDFP) that calculates the fluid properties from perturbation theory based on the insulator interatomic pair potential but including electronic excitations. The results are in agreement with several sets of experimental data in the 0.6 - 91 GPa pressure range.

  10. Bottom-up excited state dynamics of two cinnamate-based sunscreen filter molecules.

    Science.gov (United States)

    Peperstraete, Yoann; Staniforth, Michael; Baker, Lewis A; Rodrigues, Natércia D N; Cole-Filipiak, Neil C; Quan, Wen-Dong; Stavros, Vasilios G

    2016-10-12

    Methyl-E-4-methoxycinnamate (E-MMC) is a model chromophore of the commonly used commercial sunscreen agent, 2-ethylhexyl-E-4-methoxycinnamate (E-EHMC). In an effort to garner a molecular-level understanding of the photoprotection mechanisms in operation with E-EHMC, we have used time-resolved pump-probe spectroscopy to explore E-MMC's and E-EHMC's excited state dynamics upon UV-B photoexcitation to the S 1 (1 1 ππ*) state in both the gas- and solution-phase. In the gas-phase, our studies suggest that the excited state dynamics are driven by non-radiative decay from the 1 1 ππ* to the S 3 (1 1 nπ*) state, followed by de-excitation from the 1 1 nπ* to the ground electronic state (S 0 ). Using both a non-polar-aprotic solvent, cyclohexane, and a polar-protic solvent, methanol, we investigated E-MMC and E-EHMC's photochemistry in a more realistic, 'closer-to-shelf' environment. A stark change to the excited state dynamics in the gas-phase is observed in the solution-phase suggesting that the dynamics are now driven by efficient E/Z isomerisation from the initially photoexcited 1 1 ππ* state to S 0 .

  11. The structure of nuclear states at low, intermediate and high excitation energies

    International Nuclear Information System (INIS)

    Soloviev, V.G.

    1976-01-01

    It is shown that within the model based on the quasiparticle-phonon interaction one can obtain the description of few-quasiparticle components of nuclear states at low, intermediate and high excitation energies. For the low-lying states the energy of each level is calculated. The few-quasiparticle components at intermediate and high excitation energies are represented to be averaged in certain energy intervals and their characteri stics are given as the corresponding strength functions. The fragmentation of single-particle states in deformed nuclei is studied. It is shown that in the distribution of the single-particle strength alongside with a large maximum there appear local maxima and the distribution itself has a long tail. The dependence of neutron strength functions on the excitation energy is investigated for the transfer reaction of the type (d,p) and (d,t). The s,- p,- and d-wave neutron strength functions are calculated at the neutron binding energy Bn. A satisfactory agreement with experiment is obtained. The energies and Elambda-strength functions for giant multipole resonances in deformed nuclei are calculated. The energies of giant quadrupole and octupole resonances are calculated. Their widths and fine structure are being studied. It is stated that to study the structure of highly excited states it is necessary to find the values of many-quasiparticle components of the wave functions. The ways of experimental determination of these components based on the study of γ-transitions between highly excited states are discussed

  12. Coulomb ionization of inner shells by heavy charged particles

    International Nuclear Information System (INIS)

    Lapicki, G.

    1975-01-01

    The theory of inner-shell Coulomb ionization by heavy charged particles, of atomic number small compared to the target atomic number, is developed through the extension of work by Brandt and his coworkers for K shells to L shells. In slow collisions relative to the characteristic times of the inner shell electrons, the quantum-mechanical predictions in the plane-wave Born approximation (PWBA) can exceed experimental cross sections by orders of magnitude. The effects of the perturbation of the atom by and the Coulomb deflection of the particle during collisions are included in the theory. The perturbed atomic states amount to a binding of the inner-shell electrons to the moving particle in slow collisions, and to a polarization of the inner shells by the particle passing at large impact parameters during nonadiabatic collisions. These effects, not contained in the PWBA, are treated in the framework of the perturbed stationary state (PSS) theory for slow collisions and in terms of the harmonic oscillator model of Ashley, Brandt, and Ritchie for stopping powers in fast collisions. The effect of the Coulomb deflection of the particle in the field of the target nucleus on the cross sections is incorporated in the semiclassical approximation of Bang and Hansteen. Except for the lightest target atoms, the contribution of electron capture by the particles to inner-shell ionizations is shown to be negligible. The theory as developed earlier for the K shell, and here for L shells, agrees well with the vast body of experimental data on inner-shell Coulomb ionization by heavy charged particles

  13. Ultra-high resolution spectroscopy of the He doubly excited states

    International Nuclear Information System (INIS)

    Bozek, J.D.; Schlachter, A.S.; Kaindl, G.; Schulz, K.

    1995-11-01

    Photoionization spectra of the doubly-excited states of He were measured using beamline 9.0.1 at the Advanced Light Source. The beamline utilizes a 4.5 m long 8 cm period undulator as its source together with a spherical grating monochromator to provide an extremely bright source of photons in the range of 20 - 300 eV. A resolving power (E/ΔE) of 64,000 was obtained from the 1 MeV FWEM (2p,3d) doubly excited state resonance of He at 64.12 eV. The high brightness of the source and the very high quality optical elements of the beamline were all essential for achieving such a high resolution. The beamline components and operation are described and spectra of the double excitation resonances of He presented

  14. Neutral excitations in the Gaffnian state

    Science.gov (United States)

    Kang, Byungmin; Moore, Joel E.

    2017-06-01

    We study a model fractional quantum Hall (FQH) wave function called the Gaffnian state, which is believed to represent a gapless, strongly correlated state that is very different from conventional metals. To understand this exotic gapless state better, we provide a representation based on work of Halperin in which the pairing structure of the Gaffnian state becomes more explicit. We employ the single-mode approximation introduced by Girvin, MacDonald, and Platzman, here extended to three-body interactions, in order to treat a neutral collective excitation mode in order to clarify the physical origin of the gaplessness of the Gaffnian state. We discuss approaches to extract systematically the relevant physics in the long-distance, large-electron-number limit of FQH states using numerical calculations with relatively few electrons. In Appendices, we provide second-quantized expressions for many-body Haldane pseudopotentials in various geometries including the plane, sphere, cylinder, and torus based on the proper definition of the relative angular momentum.

  15. Total photoionization cross-sections of excited electronic states by the algebraic diagrammatic construction-Stieltjes-Lanczos method.

    Science.gov (United States)

    Ruberti, M; Yun, R; Gokhberg, K; Kopelke, S; Cederbaum, L S; Tarantelli, F; Averbukh, V

    2014-05-14

    Here, we extend the L2 ab initio method for molecular photoionization cross-sections introduced in Gokhberg et al. [J. Chem. Phys. 130, 064104 (2009)] and benchmarked in Ruberti et al. [J. Chem. Phys. 139, 144107 (2013)] to the calculation of total photoionization cross-sections of molecules in electronically excited states. The method is based on the ab initio description of molecular electronic states within the many-electron Green's function approach, known as algebraic diagrammatic construction (ADC), and on the application of Stieltjes-Chebyshev moment theory to Lanczos pseudospectra of the ADC electronic Hamiltonian. The intermediate state representation of the dipole operator in the ADC basis is used to compute the transition moments between the excited states of the molecule. We compare the results obtained using different levels of the many-body theory, i.e., ADC(1), ADC(2), and ADC(2)x for the first two excited states of CO, N2, and H2O both at the ground state and the excited state equilibrium or saddle point geometries. We find that the single excitation ADC(1) method is not adequate even at the qualitative level and that the inclusion of double electronic excitations for description of excited state photoionization is essential. Moreover, we show that the use of the extended ADC(2)x method leads to a substantial systematic difference from the strictly second-order ADC(2). Our calculations demonstrate that a theoretical modelling of photoionization of excited states requires an intrinsically double excitation theory with respect to the ground state and cannot be achieved by the standard single excitation methods with the ground state as a reference.

  16. Triplet Excited States as a Source of Relevant (Bio)Chemical Information

    OpenAIRE

    Jiménez Molero, María Consuelo; Miranda Alonso, Miguel Ángel

    2014-01-01

    The properties of triplet excited states are markedly medium-dependent, which turns this species into valuable tools for investigating the microenvironments existing in protein binding pockets. Monitoring of the triplet excited state behavior of drugs within transport proteins (serum albumins and alpha(1)-acid glycoproteins) by laser flash photolysis constitutes a valuable source of information on the strength of interaction, conformational freedom and protection from oxygen or other external...

  17. The role of the excited electronic states in the C++H2O reaction

    International Nuclear Information System (INIS)

    Flores, Jesus R.; Gonzalez, Adan B.

    2008-01-01

    The electronic excited states of the [COH 2 ] + system have been studied in order to establish their role in the dynamics of the C + +H 2 O→[COH] + +H reaction, which is a prototypical ion-molecule reaction. The most relevant minima and saddle points of the lowest excited state have been determined and energy profiles for the lowest excited doublet and quartet electronic states have been computed along the fragmentation and isomerization coordinates. Also, nonadiabatic coupling strengths between the ground and the first excited state have been computed where they can be large. Our analysis suggests that the first excited state could play an important role in the generation of the formyl isomer, which has been detected in crossed beam experiments [D. M. Sonnenfroh et al., J. Chem. Phys. 83, 3985 (1985)], but could not be explained in quasiclassical trajectory computations [Y. Ishikawa et al., Chem. Phys. Lett. 370, 490 (2003); J. R. Flores, J. Chem. Phys. 125, 164309 (2006)

  18. A simplified approach for the coupling of excitation energy transfer

    Energy Technology Data Exchange (ETDEWEB)

    Shi Bo [Hefei National Laboratory for Physical Science at Microscale, University of Science and Technology of China, Hefei 230026 (China); Department of Chemical Physics, University of Science and Technology of China, Hefei 230026 (China); Gao Fang, E-mail: gaofang@iim.ac.cn [Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei 230031 (China); State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences, Shenyang 110016 (China); Liang Wanzhen [Hefei National Laboratory for Physical Science at Microscale, University of Science and Technology of China, Hefei 230026 (China); Department of Chemical Physics, University of Science and Technology of China, Hefei 230026 (China)

    2012-02-06

    Highlights: Black-Right-Pointing-Pointer We propose a simple method to calculate the coupling of singlet-to-singlet and triplet-to-triplet energy transfer. Black-Right-Pointing-Pointer Coulomb term are the major contribution to the coupling of singlet-to-singlet energy transfer. Black-Right-Pointing-Pointer Effect from the intermolecular charge-transfer states dorminates in triplet-to-triplet energy transfer. Black-Right-Pointing-Pointer This method can be expanded by including correlated wavefunctions. - Abstract: A simplified approach for computing the electronic coupling of nonradiative excitation-energy transfer is proposed by following Scholes et al.'s construction on the initial and final states [G.D. Scholes, R.D. Harcourt, K.P. Ghiggino, J. Chem. Phys. 102 (1995) 9574]. The simplification is realized through defining a set of orthogonalized localized MOs, which include the polarization effect of the charge densities. The method allows calculating the coupling of both the singlet-to-singlet and triplet-to-triplet energy transfer. Numerical tests are performed for a few of dimers with different intermolecular orientations, and the results demonstrate that Coulomb term are the major contribution to the coupling of singlet-to-singlet energy transfer whereas in the case of triplet-to-triplet energy transfer, the dominant effect is arisen from the intermolecular charge-transfer states. The present application is on the Hartree-Fock level. However, the correlated wavefunctions which are normally expanded in terms of the determinant wavefunctions can be employed in the similar way.

  19. Excited states in stochastic electrodynamics

    International Nuclear Information System (INIS)

    Franca, H.M.; Marshall, T.W.

    1987-12-01

    It is shown that the set of Wigner functions associated with the excited states of the harmonic oscillator constitute a complete set of functions over the phase space. An arbitraty distribution can be expanded in terms of these Wigner functions. By studying the time evolution, according to Stochastic Electrodynamics, of the expansion coefficients, becomes feasible to separate explicity the contributionsof the radiative reaction and the vaccuum field to the Einsten. A coefficients for this system. A simple semiclassical explanation of the Weisskopf-Heitler phenomenon in resonance fluorescence is also supplied. (author) [pt

  20. The MSINDO-sCIS and MSINDO-UCIS methods. Procedures for the calculation of properties of excited states in molecules and periodic systems by a semiempirical approach

    International Nuclear Information System (INIS)

    Gadaczek, Immanuel Patrick

    2013-01-01

    Theoretical background, parameterization and performance of the newly developed semiempirical configuration interaction singles (CIS) method MSINDO-sCIS (scaled configuration interaction singles) are presented. The CIS Hamiltonian is modified by scaling of the Coulomb and exchange integrals and a semiempirical correction of the diagonal elements. For a recently proposed benchmark set of 28 medium-sized organic molecules, vertical excitation energies for singlet and triplet states have been calculated and statistically evaluated. A full reparameterization of the MSINDO method for both ground and excited state properties was performed. The results of the reparameterized MSINDO-sCIS method are compared to the currently best semiempirical method for excited states, OM3-CISDTQ by Thiel et al., and to other standard methods, such as time-dependent density- functional theory. The mean absolute deviation with respect to the theoretical best estimates (TBEs) for MSINDO-sCIS is 0.44 eV, comparable to the OM3 method but significantly smaller than for Zerner's INDO/S. The computational effort is strongly reduced compared to OM3-CISDTQ and OM3-MRCISD, since only single excitations are taken into account. Higher excitations are implicitly included by parameterization and the empirical correction term. By application of the Davidson-Liu block diagonalization method high computational efficiency is achieved. Furthermore it is demonstrated, that the MSINDO-sCIS method correctly describes charge-transfer (CT) states, that represent a crucial problem for time-dependent density functional theory (TD-DFT) methods. Additionally this method is extended to open-shell systems by the UCIS (unrestricted CIS) approach. MSINDO allows the calculation of periodic systems via the cyclic cluster model (CCM) which is a direct-space approach and therefore can be in principle combined with all molecular quantum-chemical techniques. The sCIS/UCIS equations are solved for a cluster with periodic

  1. Coulomb drag in multiwall armchair carbon nanotubes

    DEFF Research Database (Denmark)

    Lunde, A.M.; Jauho, Antti-Pekka

    2004-01-01

    surface. The cylindrical geometry of the nanotubes and the different parities of the Bloch states are accounted for in the evaluation of the effective Coulomb interaction between charges in the concentric nanotubes. We find a broad peak in rho(21) as a function of temperature at roughly T similar to 0.4T...

  2. Partial radiative-recombination cross sections for excited states of hydrogen

    International Nuclear Information System (INIS)

    Fazio, P.M.; Copeland, G.E.

    1985-01-01

    The squares of the dipole and quadrupole matrix elements for the free-to-bound transitions of hydrogen up to bound states Vertical Barn = 20,l = 19> are derived in closed analytic form as a function of the kinetic energy of the free electron. Coulomb wave functions are used for the free as well as the bound states and, thus, the results are good for any electron energy. Several interesting effects are found. First, the transition probabilities are maximum for recombination into specific intermediate-angular-momentum states at low energies (w<1 eV) and where the free-state angular momentum is greater than that of the bound state. Further, that specific intermediate-angular-momentum state depends on the kinetic energy of the free electron. This behavior is in contrast to the ''normal'' behavior of the transition strengths where recombination into s states is greatest and decreases with increasing angular momentum. Second, the quadrupole matrix elements vanish for certain velocities of the free electron. These ''zeros'' produce minima in the corresponding quadrupole cross sections. Finally, the calculated partial cross sections for recombination into high-angular-momentum states are greater when quadrupole transitions are included

  3. Many-body effects in the gain spectra of highly excited quantum-dot lasers

    International Nuclear Information System (INIS)

    Schneider, H. C.; Chow, W. W.; Koch, S. W.

    2001-01-01

    Optical gain spectra are computed for quantum dots under high excitation conditions, where there is a non-negligible two-dimensional carrier density surrounding the dots. Using a screened Hartree-Fock theory to describe the influence of the Coulomb interaction, we find different self-energy shifts for the dot and quantum-well transitions. Furthermore, in contrast to the result for quantum-well and bulk systems, the peak gain at the quantum-dot transition computed including Coulomb effects is reduced from its free carrier value

  4. Effects of crossed states on photoluminescence excitation spectroscopy of InAs quantum dots

    Directory of Open Access Journals (Sweden)

    Lin Chien-Hung

    2011-01-01

    Full Text Available Abstract In this report, the influence of the intrinsic transitions between bound-to-delocalized states (crossed states or quasicontinuous density of electron-hole states on photoluminescence excitation (PLE spectra of InAs quantum dots (QDs was investigated. The InAs QDs were different in size, shape, and number of bound states. Results from the PLE spectroscopy at low temperature and under a high magnetic field (up to 14 T were compared. Our findings show that the profile of the PLE resonances associated with the bound transitions disintegrated and broadened. This was attributed to the coupling of the localized QD excited states to the crossed states and scattering of longitudinal acoustical (LA phonons. The degree of spectral linewidth broadening was larger for the excited state in smaller QDs because of the higher crossed joint density of states and scattering rate.

  5. Nuclear moments from heavy-ion inelastic scattering above the Coulomb barrier

    International Nuclear Information System (INIS)

    Gross, E.E.

    1981-01-01

    Use of appropriate theoretical techniques allows the study of the moments of the nuclear charge distribution to be extended above the Coulomb barrier. The investigation of nuclear moments through analysis of differential cross sections is discussed with the aid of several examples: 12 C(70.4 MeV) + 144 146 Nd, importance of multistep effects; 20 Ne(131 MeV) + 208 Pb, large hexadecapole deformation; 12 C(78 MeV) + 194 Pt, asymmetric rotor model; and 22 Ne(93.5 MeV) + 126 Te, mutual excitation. 13 figures, 1 table

  6. Coulomb Impurity Problem of Graphene in Strong Coupling Regime in Magnetic Fields.

    Science.gov (United States)

    Kim, S C; Yang, S-R Eric

    2015-10-01

    We investigate the Coulomb impurity problem of graphene in strong coupling limit in the presence of magnetic fields. When the strength of the Coulomb potential is sufficiently strong the electron of the lowest energy boundstate of the n = 0 Landau level may fall to the center of the potential. To prevent this spurious effect the Coulomb potential must be regularized. The scaling function for the inverse probability density of this state at the center of the impurity potential is computed in the strong coupling regime. The dependence of the computed scaling function on the regularization parameter changes significantly as the strong coupling regime is approached.

  7. Excited states of 12C above the alpha-decay threshold

    International Nuclear Information System (INIS)

    Freer, M; Ashwood, N I; Barr, M; Curtis, N; Malcolm, J D; Wheldon, C; Ziman, V A; Almaraz-Calderon, S; Aprahamian, A; Bucher, B; Couder, M; Fang, X; Jung, F; Lu, W; Roberts, A; Tan, W P; Copp, P; Lesher, S

    2011-01-01

    The excitation energy spectrum of 12 C is important for both structural and astrophysical reasons; here we present evidence for a new state in 12 C. The two reactions 12 C( 4 He, 4 He+ 4 He+ 4 He) 4 He and 9 Be( 4 He, 4 He+ 4 He+ 4 He)n were measured using an array of four double sided strip detectors. Excited states in 12 C were reconstructed filtered by the condition that the alpha-decay proceeded via the 8 Be ground-state. In both measurements evidence was found for a new state at 13.3(0.2) MeV with a width 1.7(0.2) MeV. Angular correlation measurements from the 12 C( 4 He, 4 He+ 4 He+ 4 He) 4 He reaction indicates that the state may have J π = 4 + .

  8. Calculation of neutral beam deposition accounting for excited states

    International Nuclear Information System (INIS)

    Gianakon, T.A.

    1992-09-01

    Large-scale neutral-beam auxillary heating of plasmas has led to new plasma operational regimes which are often dominated by fast ions injected via the absorption of an energetic beam of hydrogen neutrals. An accurate simulation of the slowing down and transport of these fast ions requires an intimate knowledge of the hydrogenic neutral deposition on each flux surface of the plasma. As a refinement to the present generation of transport codes, which base their beam deposition on ground-state reaction rates, a new set of routines, based on the excited states of hydrogen, is presented as mechanism for computing the attenuation and deposition of a beam of energetic neutrals. Additionally, the numerical formulations for the underlying atomic physics for hydrogen impacting on the constiuent plasma species is developed and compiled as a numerical database. Sample results based on this excited state model are compared with the ground-state model for simple plasma configurations

  9. Dark excited states of carotenoids: Consensus and controversy

    Czech Academy of Sciences Publication Activity Database

    Polívka, Tomáš; Sundström, V.

    2009-01-01

    Roč. 477, 1-3 (2009), s. 1-11 ISSN 0009-2614 Institutional research plan: CEZ:AV0Z50510513 Keywords : carotenoids * excited states * relaxation pathways * femtosecond spectroscopy Subject RIV: BO - Biophysics Impact factor: 2.291, year: 2009

  10. Effective Kratzer and Coulomb potentials as limit cases of a multiparameter exponential-type potential

    Energy Technology Data Exchange (ETDEWEB)

    García-Ravelo, J., E-mail: g.ravelo@hotmail.com [Departamento de Física, Escuela Superior de Física y Matemáticas, Instituto Politécnico Nacional, Edificio 9, Unidad Profesional Adolfo López Mateos, México D.F., 07738 (Mexico); Menéndez, A.; García-Martínez, J. [Departamento de Física, Escuela Superior de Física y Matemáticas, Instituto Politécnico Nacional, Edificio 9, Unidad Profesional Adolfo López Mateos, México D.F., 07738 (Mexico); Schulze-Halberg, A. [Department of Mathematics and Actuarial Science and Department of Physics, Indiana University Northwest, 3400 Broadway, Gary, IN 46408 (United States)

    2014-06-13

    We show that the effective Kratzer and Coulomb potentials can be obtained by taking particular limits of a multiparameter exponential potential that was studied recently. Moreover, we demonstrate that the bound state solutions of the exponential potential reduce correctly to their well-known counterparts associated with the Kratzer and Coulomb potentials. As a byproduct, we obtain a new limit relation for the hypergeometric function. - Highlights: • Kratzer and Coulomb potentials are limit cases of an exponential-type potential. • From exact s-waves, approximate solutions for l-waves are obtained. • l-waves of the potential tend to the solutions of the Kratzer and Coulomb potentials. • A non-evident identity between hypergeometric functions is demonstrated.

  11. Effective Kratzer and Coulomb potentials as limit cases of a multiparameter exponential-type potential

    International Nuclear Information System (INIS)

    García-Ravelo, J.; Menéndez, A.; García-Martínez, J.; Schulze-Halberg, A.

    2014-01-01

    We show that the effective Kratzer and Coulomb potentials can be obtained by taking particular limits of a multiparameter exponential potential that was studied recently. Moreover, we demonstrate that the bound state solutions of the exponential potential reduce correctly to their well-known counterparts associated with the Kratzer and Coulomb potentials. As a byproduct, we obtain a new limit relation for the hypergeometric function. - Highlights: • Kratzer and Coulomb potentials are limit cases of an exponential-type potential. • From exact s-waves, approximate solutions for l-waves are obtained. • l-waves of the potential tend to the solutions of the Kratzer and Coulomb potentials. • A non-evident identity between hypergeometric functions is demonstrated

  12. Collective excitations in circular atomic configurations and single-photon traps

    International Nuclear Information System (INIS)

    Hammer, Hanno

    2004-01-01

    Correlated excitations in a plane circular configuration of identical atoms with parallel dipole moments are investigated. The collective energy eigenstates, which are formally identical to Frenkel excitons, can be computed together with their level shifts and decay rates by decomposing the atomic state space into carrier spaces for the irreducible representations of the symmetry group Z N of the circle. It is shown that the index p of these representations can be used as a quantum number analogously to the orbital angular momentum quantum number l in hydrogenlike systems. Just as the hydrogen s states are the only electronic wave functions which can occupy the central region of the Coulomb potential, the quasiparticle corresponding to a collective excitation of the atoms in the circle can occupy the central atom only for vanishing Z N quantum number p. If a central atom is present, the p=0 state splits into two and shows level crossing at certain radii; in the regions between these radii, damped quantum beats between two 'extreme' p=0 configurations occur. The physical mechanisms behind super- and subradiance at a given radius are discussed. It is shown that, beyond a certain critical number of atoms in the circle, the lifetime of the maximally subradiant state increases exponentially with the number of atoms in the configuration, making the system a natural candidate for a single-photon trap

  13. Evidence for excited state intramolecular charge transfer in benzazole-based pseudo-stilbenes.

    Science.gov (United States)

    Santos, Fabiano da Silveira; Descalzo, Rodrigo Roceti; Gonçalves, Paulo Fernando Bruno; Benvenutti, Edilson Valmir; Rodembusch, Fabiano Severo

    2012-08-21

    Two azo compounds were obtained through the diazotization reaction of aminobenzazole derivatives and N,N-dimethylaniline using clay montmorillonite KSF as catalyst. The synthesized dyes were characterized using elemental analysis, Fourier transform infrared spectroscopy, and (13)C and (1)H NMR spectroscopy in solution. Their photophysical behavior was studied using UV-vis and steady-state fluorescence in solution. These dyes present intense absorption in the blue region. The spectral features of the azo compounds can be related to the pseudo-stilbene type as well as the E isomer of the dyes. Excitation at the absorption maxima does not produce emissive species in the excited state. However, excitation around 350 nm allowed dual emission of fluorescence, from both a locally excited (LE, short wavelength) and an intramolecular charge transfer (ICT, long wavelength) state, which was corroborated by a linear relation of the fluorescence maximum (ν(max)) versus the solvent polarity function (Δf) from the Lippert-Mataga correlation. Evidence of TICT in these dyes was discussed from the viscosity dependence of the fluorescence intensity in the ICT emission band. Theoretical calculations were also performed in order to study the geometry and charge distribution of the dyes in their ground and excited electronic states. Using DFT methods at the theoretical levels BLYP/Aug-cc-pVDZ, for geometry optimizations and frequency calculations, and B3LYP/6-311+G(2d), for single-point energy evaluations, the calculations revealed that the least energetic and most intense photon absorption leads to a very polar excited state that relaxes non-radioactively, which can be associated with photochemical isomerization.

  14. Radiative and Excited State Charmonium Physics

    Energy Technology Data Exchange (ETDEWEB)

    Jozef Dudek

    2007-07-30

    Renewed interest in the spectroscopy of charmonium has arisen from recent unexpected observations at $e^+e^-$ colliders. Here we report on a series of works from the previous two years examining the radiative physics of charmonium states as well as the mass spectrum of states of higher spin and internal excitation. Using new techniques applied to Domain-Wall and Clover quark actions on quenched isotropic and anisotropic lattices, radiative transitions and two-photon decays are considered for the first time. Comparisons are made with experimental results and with model approaches. Forthcoming application to the light-quark sector of relevance to experiments like Jefferson Lab's GlueX is discussed.

  15. Self-Consistent Monte Carlo Study of the Coulomb Interaction under Nano-Scale Device Structures

    Science.gov (United States)

    Sano, Nobuyuki

    2011-03-01

    It has been pointed that the Coulomb interaction between the electrons is expected to be of crucial importance to predict reliable device characteristics. In particular, the device performance is greatly degraded due to the plasmon excitation represented by dynamical potential fluctuations in high-doped source and drain regions by the channel electrons. We employ the self-consistent 3D Monte Carlo (MC) simulations, which could reproduce both the correct mobility under various electron concentrations and the collective plasma waves, to study the physical impact of dynamical potential fluctuations on device performance under the Double-gate MOSFETs. The average force experienced by an electron due to the Coulomb interaction inside the device is evaluated by performing the self-consistent MC simulations and the fixed-potential MC simulations without the Coulomb interaction. Also, the band-tailing associated with the local potential fluctuations in high-doped source region is quantitatively evaluated and it is found that the band-tailing becomes strongly dependent of position in real space even inside the uniform source region. This work was partially supported by Grants-in-Aid for Scientific Research B (No. 2160160) from the Ministry of Education, Culture, Sports, Science and Technology in Japan.

  16. Selective two-photon excitation of a vibronic state by correlated photons.

    Science.gov (United States)

    Oka, Hisaki

    2011-03-28

    We theoretically investigate the two-photon excitation of a molecular vibronic state by correlated photons with energy anticorrelation. A Morse oscillator having three sets of vibronic states is used, as an example, to evaluate the selectivity and efficiency of two-photon excitation. We show that a vibrational mode can be selectively excited with high efficiency by the correlated photons, without phase manipulation or pulse-shaping techniques. This can be achieved by controlling the quantum correlation so that the photon pair concurrently has two pulse widths, namely, a temporally narrow width and a spectrally narrow width. Though this concurrence is seemingly contradictory, we can create such a photon pair by tailoring the quantum correlation between two photons.

  17. Amplitudes and state parameters from ion- and atom-atom excitation processes

    International Nuclear Information System (INIS)

    Andersen, T.; Horsdal-Pedersen, E.

    1984-01-01

    This chapter examines single collisions between two atomic species, one of which is initially in a 1 S state (there is only one initial spin channel). The collisions are characterized by a definite scattering plane and a definite orientation. Topics considered include an angular correlation between scattered particles and autoionization electrons or polarized photons emitted from states excited in atomic collisions (photon emission, electron emission, selectivity excited target atoms), experimental methods for obtaining information on the alignment and orientation parameters of atoms or ions excited in specific collisions, results of experiments and numerical calculations (quasi-oneelectron systems, He + -He collisions, other collision systems), and future aspects and possible applications of the polarizedphoton, scattered-particle coincidence techniques to atomic spectroscopy

  18. Correction of the near threshold behavior of electron collisional excitation cross-sections in the plane-wave Born approximation

    Science.gov (United States)

    Kilcrease, D. P.; Brookes, S.

    2013-12-01

    The modeling of NLTE plasmas requires the solution of population rate equations to determine the populations of the various atomic levels relevant to a particular problem. The equations require many cross sections for excitation, de-excitation, ionization and recombination. A simple and computational fast way to calculate electron collisional excitation cross-sections for ions is by using the plane-wave Born approximation. This is essentially a high-energy approximation and the cross section suffers from the unphysical problem of going to zero near threshold. Various remedies for this problem have been employed with varying degrees of success. We present a correction procedure for the Born cross-sections that employs the Elwert-Sommerfeld factor to correct for the use of plane waves instead of Coulomb waves in an attempt to produce a cross-section similar to that from using the more time consuming Coulomb Born approximation. We compare this new approximation with other, often employed correction procedures. We also look at some further modifications to our Born Elwert procedure and its combination with Y.K. Kim's correction of the Coulomb Born approximation for singly charged ions that more accurately approximate convergent close coupling calculations.

  19. Dual structure in the charge excitation spectrum of electron-doped cuprates

    Science.gov (United States)

    Bejas, Matías; Yamase, Hiroyuki; Greco, Andrés

    2017-12-01

    Motivated by the recent resonant x-ray scattering (RXS) and resonant inelastic x-ray scattering (RIXS) experiments for electron-doped cuprates, we study the charge excitation spectrum in a layered t -J model with the long-range Coulomb interaction. We show that the spectrum is not dominated by a specific type of charge excitations, but by different kinds of charge fluctuations, and is characterized by a dual structure in the energy space. Low-energy charge excitations correspond to various types of bond-charge fluctuations driven by the exchange term (J term), whereas high-energy charge excitations are due to usual on-site charge fluctuations and correspond to plasmon excitations above the particle-hole continuum. The interlayer coupling, which is frequently neglected in many theoretical studies, is particularly important to the high-energy charge excitations.

  20. Testing the Predictive Power of Coulomb Stress on Aftershock Sequences

    Science.gov (United States)

    Woessner, J.; Lombardi, A.; Werner, M. J.; Marzocchi, W.

    2009-12-01

    Empirical and statistical models of clustered seismicity are usually strongly stochastic and perceived to be uninformative in their forecasts, since only marginal distributions are used, such as the Omori-Utsu and Gutenberg-Richter laws. In contrast, so-called physics-based aftershock models, based on seismic rate changes calculated from Coulomb stress changes and rate-and-state friction, make more specific predictions: anisotropic stress shadows and multiplicative rate changes. We test the predictive power of models based on Coulomb stress changes against statistical models, including the popular Short Term Earthquake Probabilities and Epidemic-Type Aftershock Sequences models: We score and compare retrospective forecasts on the aftershock sequences of the 1992 Landers, USA, the 1997 Colfiorito, Italy, and the 2008 Selfoss, Iceland, earthquakes. To quantify predictability, we use likelihood-based metrics that test the consistency of the forecasts with the data, including modified and existing tests used in prospective forecast experiments within the Collaboratory for the Study of Earthquake Predictability (CSEP). Our results indicate that a statistical model performs best. Moreover, two Coulomb model classes seem unable to compete: Models based on deterministic Coulomb stress changes calculated from a given fault-slip model, and those based on fixed receiver faults. One model of Coulomb stress changes does perform well and sometimes outperforms the statistical models, but its predictive information is diluted, because of uncertainties included in the fault-slip model. Our results suggest that models based on Coulomb stress changes need to incorporate stochastic features that represent model and data uncertainty.

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