Resonance-enhanced electron-impact excitation of Cu-like gold

Science.gov (United States)

Xia, L.; Zhang, C. Y.; Si, R.; Guo, X. L.; Chen, Z. B.; Yan, J.; Li, S.; Chen, C. Y.; Wang, K.

2017-09-01

Employing the independent-process and isolated-resonance approximations using distorted-waves (IPIRDW), we have performed a series of calculations of the resonance-enhanced electron-impact excitations (EIE) among 27 singly excited levels from the n ≤ 6 configurations of Cu-like gold (Au, Z = 79). Resonance excitation (RE) contributions from both the n = 4 → 4 - 7 and n = 3 → 4 core excitations have been considered. Our results demonstrate that RE contributions are significant and enhance the effective collision strengths (ϒ) of certain excitations by up to an order of magnitude at low temperature (106.1 K), and are still important at relatively high temperature (107.5 K). Results from test calculations of the resonance-enhanced EIE processes among 16 levels from the n ≤ 5 configurations using both the Dirac R-matrix (DRM) and IPIRDW approaches agree very well with each other. This means that the close-coupling effects are not important for this ion, and thus warrants the reliability of present resonance-enhanced EIE data among the 27 levels. The results from the collisional-radiative model (CRM) show that, at 3000 eV, near where Cu-like Au is most abundant, RE contributions have important effects (up to 25%) on the density diagnostic line intensity ratios, which are sensitive near 1020 cm-3. The present work is the first EIE research including RE contributions for Cu-like Au. Our EIE data are more accurate than previous results due to our consideration of RE contributions, and the data should be helpful for modeling and diagnosing a variety of plasmas.

Nuclear isovector giant resonances excited by pion single charge exchange

International Nuclear Information System (INIS)

King, B.H.

1993-07-01

This thesis is an experimental study of isovector giant resonances in light nuclei excited by pion single charge exchange reactions. Giant dipole resonances in light nuclei are known to be highly structured. For the mass 9 and 13 giant dipole resonances, isospin considerations were found to be very important to understanding this structure. by comparing the excitation functions from cross section measurements of the (π + , π 0 ) and (π, π 0 ) inclusive reactions, the authors determined the dominant isospin structure of the analog IVGR's. The comparison was made after decomposing the cross section into resonant and non-resonant components. This decomposition is made in the framework of strong absorption and quasi-free scattering. Measurements in the region of the isovector giant dipole resonances (IVGDR) were made to cover the inclusive angular distributions out to the second minimum. Study of the giant resonance decay process provides further understanding of the resonances. This study was carried out by observing the (π + , π 0 p) coincident reactions involving the resonances of 9 B and 13 N excited from 9 Be and 13 C nuclei. These measurements determined the spectra of the decay protons. This method also permitted a decomposition of the giant resonances into their isospin components. The multipolarities of the resonances were revealed by the decay proton angular correlations which, for dipoles, are of the form 1 + A 2 P 2 (cos θ)

Mixed frequency excitation of an electrostatically actuated resonator

KAUST Repository

Ramini, Abdallah

2015-04-24

We investigate experimentally and theoretically the dynamics of a capacitive resonator under mixed frequency excitation of two AC harmonic signals. The resonator is composed of a proof mass suspended by two cantilever beams. Experimental measurements are conducted using a laser Doppler vibrometer to reveal the interesting dynamics of the system when subjected to two-source excitation. A nonlinear single-degree-of-freedom model is used for the theoretical investigation. The results reveal combination resonances of additive and subtractive type, which are shown to be promising to increase the bandwidth of the resonator near primary resonance frequency. Our results also demonstrate the ability to shift the combination resonances to much lower or much higher frequency ranges. We also demonstrate the dynamic pull-in instability under mixed frequency excitation. © 2015 Springer-Verlag Berlin Heidelberg

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.

On the resonant coherent excitation of relativistic heavy ions

International Nuclear Information System (INIS)

Pivovarov, Y.L.; Geissel, H.; Filimonov, Yu.M.; Krivosheev, O.E.; Scheidenberger, C.

1995-07-01

New accelerator facilities open up an interesting new field of experiments on basic channeling as well as on atomic and nuclear resonant coherent exitation (RCE) of heavy ions penetrating through aligned crystals at relativistic energies. Results of computer simulations are presented to characterize the resonant coherent excitation of atomic levels of relativistic hydrogen-like heavy ions. Nuclear resonant coherent excitation reveals interesting different characteristics compared to the corresponding atomic excitation inside crystals. An important result of our model calculations is that poorly-channeled ions have a higher nuclear excitation probability than well-channeled ions. (orig.)

Creation of skyrmion through resonance excitation

Energy Technology Data Exchange (ETDEWEB)

Li, Zhi-xiong; Chen, Yi-fu; Zhou, Zhen-wei; Nie, Yao-zhuang; Xia, Qing-lin; Wang, Dao-wei; Guo, Guang-hua, E-mail: guogh@mail.csu.edu.cn

2017-07-01

Highlights: • Intrinsic oscillation modes of skyrmion are studied by using micromagnetic simulation. • Creation of skyrmion through resonant excitation is proposed. • The number of generated skyrmions can be effectively controlled by manipulating the driving field. • Skyrmion lattice in extended film is generated via resonant excitation. - Abstract: Controllable creation of magnetic skyrmions in nanostructures is a prerequisite for the application of skyrmions in spintronics. Here, we propose a new method for the creation of skyrmions. We show by using micromagnetic simulations that the skyrmions can be nucleated by resonantly exciting one of the skyrmion intrinsic oscillation modes. We first studied the dynamics of skyrmion in a ferromagnetic nanodisk with perpendicular anisotropy. One breathing mode and two non-degenerate gyrotropic modes are identified. Then we applied a circular-polarized microwave field to excite the uniformly magnetized nanodisk. When the frequency of the driving field is equal to the eigenfrequency of the skyrmion gyrotropic mode, stable skyrmions can be created from the initial uniform state. The number of skyrmions can be effectively controlled by appropriately choosing the duration of the driving field or tuning the field amplitude.

Theoretical resonant electron-impact vibrational excitation, dissociative recombination and dissociative excitation cross sections of ro-vibrationally excited BeH"+ ion

International Nuclear Information System (INIS)

Laporta, V.; Chakrabarti, K.; Celiberto, R.; Janev, R. K.; Mezei, J. Zs.; Niyonzima, S.; Tennyson, J.; Schneider, I.F.

2017-01-01

A theoretical study of resonant vibrational excitation, dissociative recombination and dissociative excitation processes of the beryllium monohydride cation, BeH"+ , induced by electron impact, is reported. Full sets of ro-vibrationally-resolved cross sections and of the corresponding Maxwellian rate coefficients are presented for the three processes. Particular emphasis is given to the high-energy behaviour. Potential curves of "2σ"+, "2σ and "2δ symmetries and the corresponding resonance widths, obtained from R-matrix calculations, provide the input for calculations which use a local complex-potential model for resonant collisions in each of the three symmetries. Rotational motion of nuclei and isotopic effects are also discussed. The relevant results are compared with those obtained using a multichannel quantum defect theory method. Full results are available from the Phys4Entry database.

Resonant-cantilever bio/chemical sensors with an integrated heater for both resonance exciting optimization and sensing repeatability enhancement

International Nuclear Information System (INIS)

Yu Haitao; Li Xinxin; Gan Xiaohua; Liu Yongjing; Liu Xiang; Xu Pengcheng; Li Jungang; Liu Min

2009-01-01

With an integrated resonance exciting heater and a self-sensing piezoresistor, resonant micro-cantilever bio/chemical sensors are optimally designed and fabricated by micromachining techniques. This study is emphasized on the optimization of the integrated heating resistor. Previous research has put the heater at either the cantilever clamp end, the midpoint or the free end. Aiming at sufficiently high and stable resonant amplitude, our research indicates that the optimized location of the thermal-electric exciting resistor is the clamp end instead of other positions. By both theoretical analysis and resonance experiments where three heating resistors are placed at the three locations of the fabricated cantilever, it is clarified that the clamp end heating provides the most efficient resonance excitation in terms of resonant amplitude, Q-factor and resonance stability. Besides, the optimized combination of dc bias and ac voltage is determined by both analysis and experimental verification. With the optimized heating excitation, the resonant cantilever is used for biotin–avidin-specific detection, resulting in a ±0.1 Hz ultra-low noise floor of the frequency signal and a 130 fg mass resolution. In addition to resonance excitation, the heater is used to heat up the cantilever for speed-up desorption after detection that helps rapid and repeated sensing to chemical vapor. The clamp end is determined (by simulation) as the optimal heating location for uniform temperature distribution on the cantilever. Using the resonant cantilever, a rapid and repeated sensing experiment on dimethyl methylphosphonate (DMMP) vapor shows that a short-period heating at the detection interval significantly quickens the signal recovery and enhances the sensing repeatability

Design and implementation of improved LsCpLp resonant circuit for power supply for high-power electromagnetic acoustic transducer excitation

Science.gov (United States)

Zao, Yongming; Ouyang, Qi; Chen, Jiawei; Zhang, Xinglan; Hou, Shuaicheng

2017-08-01

This paper investigates the design and implementation of an improved series-parallel inductor-capacitor-inductor (LsCpLp) resonant circuit power supply for excitation of electromagnetic acoustic transducers (EMATs). The main advantage of the proposed resonant circuit is the absence of a high-permeability dynamic transformer. A high-frequency pulsating voltage gain can be achieved through a double resonance phenomenon. Both resonant tailing behavior and higher harmonics are suppressed by the improved resonant circuit, which also contributes to the generation of ultrasonic waves. Additionally, the proposed circuit can realize impedance matching and can also optimize the transduction efficiency. The complete design and implementation procedure for the power supply is described and has been validated by implementation of the proposed power supply to drive a portable EMAT. The circuit simulation results show close agreement with the experimental results and thus confirm the validity of the proposed topology. The proposed circuit is suitable for use as a portable EMAT excitation power supply that is fed by a low-voltage source.

Design and implementation of improved LsCpLp resonant circuit for power supply for high-power electromagnetic acoustic transducer excitation.

Science.gov (United States)

Zao, Yongming; Ouyang, Qi; Chen, Jiawei; Zhang, Xinglan; Hou, Shuaicheng

2017-08-01

This paper investigates the design and implementation of an improved series-parallel inductor-capacitor-inductor (L s C p L p ) resonant circuit power supply for excitation of electromagnetic acoustic transducers (EMATs). The main advantage of the proposed resonant circuit is the absence of a high-permeability dynamic transformer. A high-frequency pulsating voltage gain can be achieved through a double resonance phenomenon. Both resonant tailing behavior and higher harmonics are suppressed by the improved resonant circuit, which also contributes to the generation of ultrasonic waves. Additionally, the proposed circuit can realize impedance matching and can also optimize the transduction efficiency. The complete design and implementation procedure for the power supply is described and has been validated by implementation of the proposed power supply to drive a portable EMAT. The circuit simulation results show close agreement with the experimental results and thus confirm the validity of the proposed topology. The proposed circuit is suitable for use as a portable EMAT excitation power supply that is fed by a low-voltage source.

Flow-excited acoustic resonance excitation mechanism, design guidelines, and counter measures

International Nuclear Information System (INIS)

Ziada, Samir; Lafon, Philippe

2014-01-01

The excitation mechanism of acoustic resonances has long been recognized, but the industry continues to be plagued by its undesirable consequences, manifested in severe vibration and noise problems in a wide range of industrial applications. This paper focuses on the nature of the excitation mechanism of acoustic resonances in piping systems containing impinging shear flows, such as flow over shallow and deep cavities. Since this feedback mechanism is caused by the coupling between acoustic resonators and shear flow instabilities, attention is focused first on the nature of various types of acoustic resonance modes and then on the aero-acoustic sound sources, which result from the interaction of the inherently unstable shear flow with the sound field generated by the resonant acoustic modes. Various flow-sound interaction patterns are discussed, in which the resonant sound field can be predominantly parallel or normal to the mean flow direction and the acoustic wavelength can be an order of magnitude longer than the length scale of the separated shear flow or as short as the cavity length scale. Since the state of knowledge in this field has been recently reviewed by Tonon et al. (2011, 'Aero-acoustics of Pipe Systems With Closed Branches', Int. J. Aeroacoust., 10(2), pp. 201-276), this article focuses on the more practical aspects of the phenomenon, including various flow sound interaction patterns and the resulting aero-acoustic sources, which are relevant to industrial applications. A general design guide proposal and practical means to alleviate the excitation mechanism are also presented. These are demonstrated by two examples of recent industrial case histories dealing with acoustic fatigue failure of the steam dryer in a boiling water reactor (BWR) due to acoustic resonance in the main steam piping and acoustic resonances in the roll posts of the Short Take-Off and Vertical Lift Joint Strike Fighter (JSF). (authors)

Experimental results of high power dual frequency resonant magnet excitation at TRIUMF

International Nuclear Information System (INIS)

Reiniger, K.W.; Heritier, G.

1988-06-01

We present some results of duel frequency resonant magnet excitation at full power using the old NINA synchrotron dipoles. These tests will simulate a typical resonant cell as proposed for the accelerating rings of the TRIUMF KAON Factory. These test have two main purposes: to verify circuit parameters and component ratings for the dual frequency resonant power supply system; and to measure directly electrical losses in a transverse magnet field, such as eddy current losses in magnet conductors, vacuum tubes and core losses in laminations. These data will be required for the detailed design of the accelerator system components. (Author) (Ref., 9 figs., tab.)

Off-resonant vibrational excitation: Orientational dependence and spatial control of photofragments

DEFF Research Database (Denmark)

Machholm, Mette; Henriksen, Niels Engholm

2000-01-01

Off-resonant and resonant vibrational excitation with short intense infrared (IR) laser pulses creates localized oscillating wave packets, but differs by the efficiency of the excitation and surprisingly by the orientational dependence. Orientational selectivity of the vibrational excitation...... of randomly oriented heteronuclear diatomic molecules can be obtained under simultaneous irradiation by a resonant and an off-resonant intense IR laser pulse: Molecules with one initial orientation will be vibrationally excited, while those with the opposite orientation will be at rest. The orientation-dependent...... distribution. (C) 2000 American Institute of Physics....

Hadron excitation of giant resonances

International Nuclear Information System (INIS)

Morsch, H.-P.

1985-01-01

A review is given on giant resonance studies in heavy nuclei using scattering of different hadronic probes. Concerning isoscalar giant resonances compression modes are discussed with the possibility to obtain more detailed structure information. From detailed studies of α scattering the distribution of isoscalar strengths of multipolarity up to L=6 was obtained. Some recent aspects of heavy ion excitation of collective modes are mentioned. The possibility to study isovector giant resonances in hadron charge exchange reactions is discussed. Finally, a comparison is made between α and 200 MeV proton scattering from which isoscalar and spin-isospin continuum response are extracted. (orig.)

Quantification of entanglement entropies for doubly excited resonance states in two-electron atomic systems

International Nuclear Information System (INIS)

Ho, Yew Kam; Lin, Chien-Hao

2015-01-01

In this work, we study the quantum entanglement for doubly excited resonance states in two-electron atomic systems such as the H - and Ps - ions and the He atom by using highly correlated Hylleraas type functions The resonance states are determined by calculation of density of resonance states with the stabilization method. The spatial (electron-electron orbital) entanglement entropies (linear and von Neumann) for the low-lying doubly excited states are quantified using the Schmidt-Slater decomposition method. (paper)

The character of resonant charge exchange involving highly excited atoms

International Nuclear Information System (INIS)

Kosarim, A. V.; Smirnov, B. M.; Capitelli, M.; Laricchiuta, A.

2012-01-01

We study the process of resonant charge exchange involving excited helium atoms with the principal quantum number n = 5 colliding with the helium ion in the ground state in the collision energy range from thermal up to 10 eV. This information may be important for the analysis of planet atmospheres containing helium, in particular, for Jupiter’s atmosphere, but our basic interest is the transition from the quantum to classical description of this process, where, due to large cross sections, evaluations of the cross sections are possible. For the chosen process, quantum theory allows determining the cross section as a result of a tunnel electron transition, while classical theory accounts for over-barrier electron transitions. The classical theory additionally requires effective transitions between states with close energies. The analysis of these transitions for helium with n = 5 shows that electron momenta and their projections are mixed for a part of the states, while for other states, the mixing is absent. A simple criterion to separate such states is given. In addition, the main contribution to the cross section of resonant charge exchange follows from tunnel electron transitions. As a result, the quantum theory is better for calculating the cross sections of resonant charge exchange than the classical one and also allows finding the partial cross sections of resonant charge exchange, while the classical approach gives the cross section of resonant charge exchange in a simple manner with the accuracy of 20%.

Nuclear-excited Feshbach resonances in the electron scattering from hydrogen halides

International Nuclear Information System (INIS)

Knoth, G.; Gote, M.; Radle, M.; Jung, K.; Ehrhardt, H.

1989-01-01

The energy dependences of the differential cross sections for the electron impact excitation of the higher vibrational levels (v=2 and v=3) of HF and HCl have been measured. Besides the threshold peak a resonance structure has been observed in the v=3 excitation functions of HF below the cusp structure at the opening of the v=4 channel. This resonance structure is the first experimental proof for the existence of the nuclear-excited Feshbach resonances which are interpreted to be the origin of the threshold peaks in the vibrational excitation channels

Excitation of resonances of microspheres on an optical fiber

Science.gov (United States)

Serpengüzel, A.; Arnold, S.; Griffel, G.

1995-04-01

Morphology-dependent resonances (MDR's) of solid microspheres are excited by using an optical fiber coupler. The narrowest measured MDR linewidths are limited by the excitation laser linewidth ( < 0.025 nm). Only MDR's, with an on-resonance to off-resonance intensity ratio of 104, contribute to scattering. The intensity of various resonance orders is understood by the localization principle and the recently developed generalized Lorentz-Mie theory. The microsphere fiber system has potential for becoming a building block in dispersive microphotonics. The basic physics underlying our approach may be considered a harbinger for the coupling of active photonic microstructures such as microdisk lasers.

Effect of high-frequency excitation on natural frequencies of spinning discs

DEFF Research Database (Denmark)

Hansen, Morten Hartvig

2000-01-01

The effect of high-frequency, non-resonant parametric excitation on the low-frequency response of spinning discs is considered. The parametric excitation is obtained through a non-constant rotation speed, where the frequency of the pulsating overlay is much higher than the lowest natural frequenc......The effect of high-frequency, non-resonant parametric excitation on the low-frequency response of spinning discs is considered. The parametric excitation is obtained through a non-constant rotation speed, where the frequency of the pulsating overlay is much higher than the lowest natural...

Self-resonant wakefield excitation by intense laser pulse in plasmas

International Nuclear Information System (INIS)

Andreev, N.E.; Pogosova, A.A.; Gorbunov, L.M.; Ramazashvili, R.R.; Kirsanov, V.I.

1993-01-01

It is demonstrated by theoretical analysis and numerical calculations that in an underdense plasma the process of three-dimensional evolution of the short and strong laser pulse (with duration equal to several plasma periods) leads to compression and self-modulation of the pulse, so that during a fairly long period of time beats of pulse amplitude generates resonantly a strong and stable plasma wakefield. The intensity of the wake-field is so high that it can provide a new promising outlook for the plasma based accelerator concept. Linear analysis of dispersion relation predicts that taking into account transverse component of wavenumber considerably increases the growth rate of resonance instability of the pulse. The numerical simulations demonstrate that considered self-focusing and resonant-modulation instability are essentially three dimensional processes. Laser field evolution in each transverse cross section of the pulse is synchronized by the regular structure of plasma wave that is excited by the pulse. The considered effect of resonant modulation has a threshold. For the pulses with the intensity below the threshold the refraction dominates and no modulation appears. The studied phenomenon can be referred to as the Self-Resonant Wakefield (SRWF) excitation that is driven by self-focusing and self-modulation of laser pulse with quite a moderate initial duration. In fact, this method of excitation differs from both suggested in Ref.1 (PBWA) and in Refs.2,3 (LWFA), being even more than the combination of these concepts. Unlike the first scheme it does not require initially the two-frequency laser pulse, since the modulation here appears in the most natural way due to evolution of the pulse. In contrast with the LWFA, the considered SRWF generation scheme gives the possibility to raise the intensity of wake-excitation due to pulse self-focusing ( initial stage) and self modulation (second stage)

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

Antiferromagnetic resonance excited by oscillating electric currents

Science.gov (United States)

Sluka, Volker

2017-12-01

In antiferromagnetic materials the order parameter exhibits resonant modes at frequencies that can be in the terahertz range, making them interesting components for spintronic devices. Here, it is shown that antiferromagnetic resonance can be excited using the inverse spin-Hall effect in a system consisting of an antiferromagnetic insulator coupled to a normal-metal waveguide. The time-dependent interplay between spin torque, ac spin accumulation, and magnetic degrees of freedom is studied. It is found that the dynamics of the antiferromagnet affects the frequency-dependent conductivity of the normal metal. Further, a comparison is made between spin-current-induced and Oersted-field-induced excitation under the condition of constant power injection.

Ion cyclotron wave excitation by double resonance coupling

International Nuclear Information System (INIS)

Fasoli, A.; Good, T.N.; Paris, P.J.; Skiff, F.; Tran, M.Q.

1990-07-01

A modulated high frequency wave is used to remotely excite low frequency oscillations in a linear, strongly magnetized plasma column. An electromagnetic wave is launched as an extraordinary mode across the plasma by an external waveguide in the Upper Hybrid frequency regime f=f UH =f ce =8 GHz, with P≤2 W. By frequency modulating (at f FM =1-60 kHz, with f ci ≅30 kHz) the pump wave, the resonant layer is swept radially across the profile and perpendicularly to the field lines at f=f FM . The resulting radial oscillation of the electron linear and non linear pressure can be considered to act as a source term for the ion wave. A localized virtual antenna is thereby created inside the plasma. Measurements of the ion dielectric response (interferograms and perturbed distribution functions) via laser induced fluorescence identify the two branches (forward, or ion-acoustic-like, and backward, or Bernstein, modes) of the electrostatic dispersion relation in the ion cyclotron frequency range. By changing the modulation bandwidth, and thus the spatial excursion of the oscillating resonant layer, a control on the perpendicular wavelength of the excited mode can be exerted. In particular, the possibility of selective excitation of the ion Bernstein wave is demonstrated experimentally. (author) 38 refs., 13 figs

Doubly-resonant coherent excitation of HCI planar channeled in a Si crystal

International Nuclear Information System (INIS)

Nakano, Y; Masugi, S; Muranaka, T; Azuma, T; Kondo, C; Hatakeyama, A; Komaki, K; Yamazaki, Y; Takada, E; Murakami, T

2007-01-01

We investigated resonant coherent excitation of H-like Ar 17+ and He-like Ar 16+ ions planar channeled in a Si crystal under the V-type and ladder-type double resonance conditions. In both cases, we observed distinct enhancement in the ionized fraction of the transmitted ions when the double resonance conditions were satisfied. In the ladder-type configuration, the enhancement indicates that the doubly-excited 2p 2 state of He-like Ar 16+ was produced through doubly-resonant coherent excitation

Triple Giant Resonance Excitations: A Microscopic Approach

International Nuclear Information System (INIS)

Lanza, E.G.; Andres, M.V.; Catara, F.; Chomaz, Ph.; Fallot, M.; Scarpaci, J.A.

2007-01-01

We present, for the first time, microscopic calculations of inelastic cross sections of the triple excitation of giant resonances induced by heavy ion probes. We start from a microscopic approach based on RPA. The mixing of three-phonon states among themselves and with two- and one-phonon states is considered within a boson expansion with Pauli corrections. In this way we go beyond the standard harmonic approximations and get anharmonic excitation spectra. At the same time we also introduce non-linearities in the external field. The calculations are done by solving semiclassical coupled channel equations, the channels being superpositions of one-, two- and three-phonon states. Previous calculations for the Double Giant Resonance excitation show good agreement with experimental cross sections. The inclusion of the three phonon components confirms the previous results for the DGR and produces a strong increase in the Triple GR energy region

Photoionization study of doubly-excited helium at ultra-high resolution

Energy Technology Data Exchange (ETDEWEB)

Kaindl, G.; Schulz, K.; Domke, M. [Freie Universitaet Berlin (Germany)] [and others

1997-04-01

Ever since the pioneering work of Madden & Codling and Cooper, Fano & Prats on doubly-excited helium in the early sixties, this system may be considered as prototypical for the study of electron-electron correlations. More detailed insight into these states could be reached only much later, when improved theoretical calculations of the optically-excited {sup 1}P{sup 0} double-excitation states became available and sufficiently high energy resolution ({delta}E=4.0 meV) was achieved. This allowed a systematic investigation of the double-excitation resonances of He up to excitation energies close to the double-ionization threshold, I{sub infinity}=79.003 eV, which stimulated renewed theoretical interest into these correlated electron states. The authors report here on striking progress in energy resolution in this grazing-incidence photon-energy range of grating monochromators and its application to hitherto unobservable states of doubly-excited He. By monitoring an extremely narrow double-excitation resonance of He, with a theoretical lifetime width of less than or equal to 5 {mu}eV, a resolution of {delta}E=1.0 meV (FWHM) at 64.1 eV could be achieved. This ultra-high spectral resolution, combined with high photon flux, allowed the investigation of new Rydberg resonances below the N=3 ionization threshold, I{sub 3}, as well as a detailed comparison with ab-initio calculations.

Resonance of magnetization excited by voltage in magnetoelectric heterostructures

Science.gov (United States)

Yu, Guoliang; Zhang, Huaiwu; Li, Yuanxun; Li, Jie; Zhang, Dainan; Sun, Nian

2018-04-01

Manipulation of magnetization dynamics is critical for spin-based devices. Voltage driven magnetization resonance is promising for realizing low-power information processing systems. Here, we show through Finite Element Method (FEM) simulations that magnetization resonance in nanoscale magnetic elements can be generated by a radio frequency (rf) voltage via the converse magnetoelectric (ME) effect. The magnetization dynamics induced by voltage in a ME heterostructures is simulated by taking into account the magnetoelastic and piezoelectric coupling mechanisms among magnetization, strain and voltage. The frequency of the excited magnetization resonance is equal to the driving rf voltage frequency. The proposed voltage driven magnetization resonance excitation mechanism opens a way toward energy-efficient spin based device applications.

Microstructure ion Nuclear Spectra at High Excitation

International Nuclear Information System (INIS)

Ericson, T.E.O.

1969-01-01

The statistical microstructure of highly excited systems is illustrated by the distribution and fluctuations of levels, widths and cross-sections of nuclei both for the case of sharp resonances and the continuum case. The coexistence of simple modes of excitation with statistical effects in terms of strength functions is illustrated by isobaric analogue states. The analogy is made with similar phenomena for coherent light, is solid-state physics and high-energy physics. (author)

Resonantly enhanced production of excited fragments of gaseous molecules following core-level excitation

International Nuclear Information System (INIS)

Chen, J.M.; Lu, K.T.; Lee, J.M.; Ho, S.C.; Chang, H.W.; Lee, Y.Y.

2005-01-01

State-selective dissociation dynamics for the excited fragments of gaseous Si(CH 3 ) 2 Cl 2 following Cl 2p and Si 2p core-level excitations have been investigated by resonant photoemission spectroscopy and dispersed UV/optical fluorescence spectroscopy. The main features in the gaseous Si(CH 3 ) 2 Cl 2 fluorescence spectrum are identified as the emission from excited Si*, Si + *, CH* and H*. The core-to-Rydberg excitations at both Si 2p and Cl 2p edges lead to a noteworthy production of not only the excited atomic fragments, neutral and ionic (Si*, Si + *) but also the excited diatomic fragments (CH*). In particular, the excited neutral atomic fragments Si* are significantly reinforced. The experimental results provide deeper insight into the state-selective dissociation dynamics for the excited fragments of molecules via core-level excitation

Crossed-coil detection of two-photon excited nuclear quadrupole resonance

Science.gov (United States)

Eles, Philip T.; Michal, Carl A.

2005-08-01

Applying a recently developed theoretical framework for determining two-photon excitation Hamiltonians using average Hamiltonian theory, we calculate the excitation produced by half-resonant irradiation of the pure quadrupole resonance of a spin-3/2 system. This formalism provides expressions for the single-quantum and double-quantum nutation frequencies as well as the Bloch-Siegert shift. The dependence of the excitation strength on RF field orientation and the appearance of the free-induction signal along an axis perpendicular to the excitation field provide an unmistakable signature of two-photon excitation. We demonstrate single- and double-quantum excitation in an axially symmetric system using 35Cl in a single crystal of potassium chlorate ( ωQ = 28 MHz) with crossed-coil detection. A rotation plot verifies the orientation dependence of the two-photon excitation, and double-quantum coherences are observed directly with the application of a static external magnetic field.

Grid impedance detection via excitation of LCL-filter resonance

DEFF Research Database (Denmark)

Liserre, Marco; Blaabjerg, Frede; Teodorescu, Remus

2005-01-01

Inverters adopted in distributed power generation, active filter and UPS are often connected to the grid through an LCL-fiIter. The impedance of the LCL-fiIter has a typical frequency spectrum with a resonance peak. Hence the LCL-fiIter has to be damped in order to avoid instability. However...... the resonance of the LCL-fiIter can be also excited in a controlled way in order to individuate the resonance frequency in the spectrum (using for example the FFn. This paper proposes to use a controlled excitation to measure the grid impedance, since this one influences also the resonance frequency. This paper...... will address some possible limits, some solutions and some implementation issues (e.g. how to obtain a controlled resonance in the filter without damaging the system) in order to use the resonant peak for grid impedance detection. The analysis is validated both by simulations and experimental results....

Energy harvesting from coherent resonance of horizontal vibration of beam excited by vertical base motion

Energy Technology Data Exchange (ETDEWEB)

Lan, C. B.; Qin, W. Y. [Department of Engineering Mechanics, Northwestern Polytechnical University, Xi' an 710072 (China)

2014-09-15

This letter investigates the energy harvesting from the horizontal coherent resonance of a vertical cantilever beam subjected to the vertical base excitation. The potential energy of the system has two symmetric potential wells. So, under vertical excitation, the system can jump between two potential wells, which will lead to the large vibration in horizontal direction. Two piezoelectric patches are pasted to harvest the energy. From experiment, it is found that the vertical excitation can make the beam turn to be bistable. The system can transform vertical vibration into horizontal vibration of low frequency when excited by harmonic motion. The horizontal coherence resonance can be observed when excited by a vertical white noise. The corresponding output voltages of piezoelectric films reach high values.

Self-excited nonlinear plasma series resonance oscillations in geometrically symmetric capacitively coupled radio frequency discharges

International Nuclear Information System (INIS)

Donko, Z.; Schulze, J.; Czarnetzki, U.; Luggenhoelscher, D.

2009-01-01

At low pressures, nonlinear self-excited plasma series resonance (PSR) oscillations are known to drastically enhance electron heating in geometrically asymmetric capacitively coupled radio frequency discharges by nonlinear electron resonance heating (NERH). Here we demonstrate via particle-in-cell simulations that high-frequency PSR oscillations can also be excited in geometrically symmetric discharges if the driving voltage waveform makes the discharge electrically asymmetric. This can be achieved by a dual-frequency (f+2f) excitation, when PSR oscillations and NERH are turned on and off depending on the electrical discharge asymmetry, controlled by the phase difference of the driving frequencies

Excitation of giant monopole and quadrupole resonances

Energy Technology Data Exchange (ETDEWEB)

Ogata, H. [Osaka Univ., Suita (Japan). Research Center for Nuclear Physics; Yamagata, T.; Tanaka, M. [and others; Ikegami, H.; Muraoka, M. [eds.; Osaka Univ., Suita (Japan). Research Center for Nuclear Physics

1980-01-01

Recent studies on the giant monopole resonance (GMR) and the giant quadrupole resonance (GQR) in /sup 144/Sm and /sup 208/Pb using the ..cap alpha..-scattering performed at RCNP are summarized. The observed angular range covered 1.6/sup 0/ -- 7/sup 0/ with a coupled system of a dipole and a triplet quadrupole magnet. The incident energy was changed from 84 to 119 MeV. The resonance shapes and energy-weighted sum-rule strengths of the GMR and the GQR were reliably deduced as a function of incident energy. The quadrupole strength of --20% was found in the GMR region. The observed excitation function of the GMR was compared with the DWBA calculation, in which the Satchler's Version I was used as a form factor representing the compressional motion of the nucleus. It was found that the experimental excitation function of the GMR shows steeper decrease as lowering the incident energy than the DWBA prediction whereas that of the GQR is successfully described by the DWBA. This suggests that examination of the model describing the GMR is necessary.

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

Effect resonance radiation transfer of excitation porous silicon to I sub 2 molecules sorbed in pores

CERN Document Server

Zakharchenko, K V; Kuznetsov, M B; Chistyakov, A A; Karavanskij, V A

2001-01-01

One studies the effect of resonance radiation-free transfer of electronic excitation between silicon nanocrystals and iodine molecules sorbed in pores. The experiment procedure includes laser-induced luminescence and laser desorption mass spectrometry. One analyzes photoluminescence spectra prior to and upon iodine sorption. Excitation of iodine through the mechanism of resonance transfer is determined to result in desorption of the iodine sorbed molecules with relatively high kinetic energies (3-1 eV). One evaluated the peculiar distance of resonance transfer the approximate value of which was equal to 2 nm

Effects of classical resonances on the chaotic microwave ionization of highly excited hydrogen atoms

Energy Technology Data Exchange (ETDEWEB)

Jensen, R V

1987-05-01

Experimental measurements of the microwave ionization of highly excited hydrogen atoms with principal quantum numbers ranging from n = 32 to 90 are well described by a classical treatment of the nonlinear electron dynamics. In particular, the measurements of the threshold field for the onset of significant ionization exhibits a curious dependence on the microwave frequency with distinct peaks at rational values of the scaled frequency, n/sup 3/..cap omega.. = 1, 2/3, 1/2, 2/5, 1/3, 1/4, 1/5, which is in excellent agreement with the predictions for the onset of classical chaos in a one-dimensional model of the experiment. In the classical theory this frequency dependence of the threshold fields is due to the stabilizing effect of nonlinear resonances (''islands'') in the classical phase space which is greatly enhanced when the microwave perturbation is turned on slowly (adiabatically) as in the experiments. Quantum calculations for this one-dimensional model also exhibit this stabilizing effect due to the preferential excitation of localized quasi-energy states.

Resonant inelastic x-ray scattering studies of elementary excitations

NARCIS (Netherlands)

Ament, Lucas Johannes Peter (Luuk)

2010-01-01

Resonant Inelastic X-ray Scattering (RIXS) is an X-ray in, X-ray out technique that enables one to study the dispersion of excitations in solids. In this thesis, we investigated how various elementary excitations of transition metal oxides show up in RIXS spectra.

Resonant states in 13C and 16,17O at high excitation energy

Science.gov (United States)

Rodrigues, M. R. D.; Borello-Lewin, T.; Miyake, H.; Duarte, J. L. M.; Rodrigues, C. L.; Horodynski-Matsushigue, L. B.; Ukita, G. M.; Cappuzzello, F.; Cavallaro, M.; Foti, A.; Agodi, C.; Cunsolo, A.; Carbone, D.; Bondi, M.; De Napoli, M.; Roeder, B. T.; Linares, R.; Lombardo, I.

2014-12-01

The 9Be(6Li,d)13C and 12,13C(6Li,d)16,17O reactions were measured at the São Paulo Pelletron-Enge-Spectrograph facility at 25.5 MeV incident energy. The nuclear emulsion detection technique was applied. Several narrow resonances were populated up to approximately 17 MeV of excitation energy. An excellent energy resolution was obtained: 40 keV for 13C and 15-30 keV for 16O. The upper limit for the resonance widths were determined. Recently, d-a angular correlations were measured at θd = 0° with incident energy of 25 MeV using the LNS Tandem-MAGNEX Spectrometer facility.

Resonant states in 13C and 16,17O at high excitation energy

International Nuclear Information System (INIS)

Rodrigues, M R D; Borello-Lewin, T; Miyake, H; Duarte, J L M; Rodrigues, C L; Horodynski-Matsushigue, L B; Ukita, G M; Cappuzzello, F; Foti, A; Cavallaro, M; Agodi, C; Cunsolo, A; Carbone, D; Bondi, M; Napoli, M De; Roeder, B T; Linares, R; Lombardo, I

2014-01-01

The 9 Be( 6 Li,d) 13 C and 12,13 C( 6 Li,d) 16,17 O reactions were measured at the São Paulo Pelletron-Enge-Spectrograph facility at 25.5 MeV incident energy. The nuclear emulsion detection technique was applied. Several narrow resonances were populated up to approximately 17 MeV of excitation energy. An excellent energy resolution was obtained: 40 keV for 13 C and 15-30 keV for 16 O. The upper limit for the resonance widths were determined. Recently, d-a angular correlations were measured at θ d = 0° with incident energy of 25 MeV using the LNS Tandem-MAGNEX Spectrometer facility

Fano resonance of the ultrasensitve optical force excited by Gaussian evanescent field

International Nuclear Information System (INIS)

Yang, Yang; Li, Jiafang; Li, Zhi-Yuan

2015-01-01

In this paper, we study the angle-dependent Fano-like optical force spectra of plasmonic Ag nanoparticles, which exhibit extraordinary transformation from Lorentzian resonance to Fano resonance when excited by a Gaussian evanescent wave. We systematically analyze the behavior of this asymmetric scattering induced optical force under different conditions and find that this Fano interference-induced force is ultrasensitive to the excitation wavelength, incident angle and particle size, as well as the core–shell configuration, which could be useful for wavelength- and angle-dependent size-selective optical manipulation. The origin of this Fano resonance is further identified as the interference between the two adjacent-order multipolar plasmonic modes excited in the Ag particle under the excitation of an inhomogeneously distributed evanescent field. (paper)

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

Wakefield excitation in plasma resonator by a sequence of relativistic electron bunches

International Nuclear Information System (INIS)

Kiselev, V.A.; Linnik, A.F.; Mirny, V.I.; Onishchenko, I.N.; Uskov, V.V.

2008-01-01

Wakefield excitation in a plasma resonator by a sequence of relativistic electron bunches with the purpose to increase excited field amplitude in comparison to waveguide case is experimentally investigated. A sequence of short electron bunches is produced by the linear resonant accelerator. Plasma resonator is formed at the beam-plasma discharge in rectangular metal waveguide filled with gas and closed by metal foil at entrance and movable short-circuited plunger at exit. Measurements of wakefield amplitude are performed showing considerably higher wakefield amplitude for resonator case

Quantum Entanglement and Shannon Information Entropy for the Doubly Excited Resonance State in Positronium Negative Ion

Directory of Open Access Journals (Sweden)

Chien-Hao Lin

2015-09-01

Full Text Available In the present work, we report an investigation on quantum entanglement in the doubly excited 2s2 1Se resonance state of the positronium negative ion by using highly correlated Hylleraas type wave functions, determined by calculation of the density of resonance states with the stabilization method. Once the resonance wave function is obtained, the spatial (electron-electron orbital entanglement entropies (von Neumann and linear can be quantified using the Schmidt decomposition method. Furthermore, Shannon entropy in position space, a measure for localization (or delocalization for such a doubly excited state, is also calculated.

Compound grating structures in photonic crystals for resonant excitation of azobenzene

DEFF Research Database (Denmark)

Jahns, Sabrina; Kallweit, Christine; Adam, Jost

Photo-switchable molecules such as azobenzene are of high interest for “smart” surfaces. Such “smart” surfaces respond to external light excitation by changing their macroscopic properties. The absorbance of light on a single normal path through a layer of azobenzene immobilized on a surface......-difference time-domain (FDTD) calculations for determination of resonance positions and electric field strengths in compound grating structures. By superimposing two single-period gratings a photonic crystal can be designed supporting multiple guided mode resonances suitable to switch azobenzenes between...

UV Resonant Raman Spectrometer with Multi-Line Laser Excitation

Science.gov (United States)

Lambert, James L.; Kohel, James M.; Kirby, James P.; Morookian, John Michael; Pelletier, Michael J.

2013-01-01

A Raman spectrometer employs two or more UV (ultraviolet) laser wavel engths to generate UV resonant Raman (UVRR) spectra in organic sampl es. Resonant Raman scattering results when the laser excitation is n ear an electronic transition of a molecule, and the enhancement of R aman signals can be several orders of magnitude. In addition, the Ra man cross-section is inversely proportional to the fourth power of t he wavelength, so the UV Raman emission is increased by another fact or of 16, or greater, over visible Raman emissions. The Raman-scatter ed light is collected using a high-resolution broadband spectrograph . Further suppression of the Rayleigh-scattered laser light is provi ded by custom UV notch filters.

Excited, bound and resonant positron-atom systems

International Nuclear Information System (INIS)

Bromley, M W J; Mitroy, J

2010-01-01

Calculations have demonstrated that eleven neutral atoms can bind positrons, while many more can bind positronium. This is a short review of recent progress made in understanding some of the underlying mechanisms. The emphasis here being on configuration interaction calculations with excited state configurations. These have demonstrated the existence of a 2 P o excited state of e + Ca, which consists predominantly of a positronium cluster orbiting the Ca + ion in the L = 1 partial wave. Preliminary results are presented of excited state positron binding to a model alkali atom, where the excited 1 P o states are stable over a limited region. Implications for the unnatural parity, 2,4 S o , states of PsH, LiPs, NaPs and KPs are also discussed. The e + Mg, e + Cu, e + Zn and e + Cd systems show a lack of a 2 P o excited state, each instead possessing a low-energy p-wave shape resonance of varying strength.

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

Excited, bound and resonant positron-atom systems

Energy Technology Data Exchange (ETDEWEB)

Bromley, M W J [Department of Physics and Computational Science Research Center, San Diego State University, San Diego CA 92182 (United States); Mitroy, J, E-mail: mbromley@physics.sdsu.ed [ARC Centre for Antimatter-Matter Studies and Faculty of Education, Health and Science, Charles Darwin University, Darwin NT 0909 (Australia)

2010-01-01

Calculations have demonstrated that eleven neutral atoms can bind positrons, while many more can bind positronium. This is a short review of recent progress made in understanding some of the underlying mechanisms. The emphasis here being on configuration interaction calculations with excited state configurations. These have demonstrated the existence of a {sup 2}P{sup o} excited state of e{sup +}Ca, which consists predominantly of a positronium cluster orbiting the Ca{sup +} ion in the L = 1 partial wave. Preliminary results are presented of excited state positron binding to a model alkali atom, where the excited {sup 1}P{sup o} states are stable over a limited region. Implications for the unnatural parity, {sup 2,4}S{sup o}, states of PsH, LiPs, NaPs and KPs are also discussed. The e{sup +}Mg, e{sup +}Cu, e{sup +}Zn and e{sup +}Cd systems show a lack of a {sup 2}P{sup o} excited state, each instead possessing a low-energy p-wave shape resonance of varying strength.

Low-energy d-d excitations in MnO studied by resonant x-ray fluorescence spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Butorin, S.M.; Guo, J.; Magnuson, M. [Uppsala Univ. (Sweden)] [and others

1997-04-01

Resonant soft X-ray emission spectroscopy has been demonstrated to possess interesting abilities for studies of electronic structure in various systems, such as symmetry probing, alignment and polarization dependence, sensitivity to channel interference, etc. In the present abstract the authors focus on the feasibility of resonant soft X-ray emission to probe low energy excitations by means of resonant electronic X-ray Raman scattering. Resonant X-ray emission can be regarded as an inelastic scattering process where a system in the ground state is transferred to a low excited state via a virtual core excitation. The energy closeness to a core excitation of the exciting radiation enhances the (generally) low probability for inelastic scattering at these wavelengths. Therefore soft X-ray emission spectroscopy (in resonant electronic Raman mode) can be used to study low energy d-d excitations in transition metal systems. The involvement of the intermediate core state allows one to use the selection rules of X-ray emission, and the appearance of the elastically scattered line in the spectra provides the reference to the ground state.

Low-energy d-d excitations in MnO studied by resonant x-ray fluorescence spectroscopy

International Nuclear Information System (INIS)

Butorin, S.M.; Guo, J.; Magnuson, M.

1997-01-01

Resonant soft X-ray emission spectroscopy has been demonstrated to possess interesting abilities for studies of electronic structure in various systems, such as symmetry probing, alignment and polarization dependence, sensitivity to channel interference, etc. In the present abstract the authors focus on the feasibility of resonant soft X-ray emission to probe low energy excitations by means of resonant electronic X-ray Raman scattering. Resonant X-ray emission can be regarded as an inelastic scattering process where a system in the ground state is transferred to a low excited state via a virtual core excitation. The energy closeness to a core excitation of the exciting radiation enhances the (generally) low probability for inelastic scattering at these wavelengths. Therefore soft X-ray emission spectroscopy (in resonant electronic Raman mode) can be used to study low energy d-d excitations in transition metal systems. The involvement of the intermediate core state allows one to use the selection rules of X-ray emission, and the appearance of the elastically scattered line in the spectra provides the reference to the ground state

Resonator coupled Josephson junctions; parametric excitations and mutual locking

DEFF Research Database (Denmark)

Jensen, H. Dalsgaard; Larsen, A.; Mygind, Jesper

1991-01-01

Self-pumped parametric excitations and mutual locking in systems of Josephson tunnel junctions coupled to multimode resonators are reported. For the very large values of the coupling parameter, obtained with small Nb-Al2O3-Nb junctions integrated in superconducting microstrip resonators, the DC I......-V characteristic shows an equidistant series of current steps generated by subharmonic pumping of the fundamental resonator mode. This is confirmed by measurement of frequency and linewidth of the emitted Josephson radiation...

Highly excited bound-state resonances of short-range inverse power-law potentials

Energy Technology Data Exchange (ETDEWEB)

Hod, Shahar [The Ruppin Academic Center, Emeq Hefer (Israel); The Hadassah Academic College, Jerusalem (Israel)

2017-11-15

We study analytically the radial Schroedinger equation with long-range attractive potentials whose asymptotic behaviors are dominated by inverse power-law tails of the form V(r) = -β{sub n}r{sup -n} with n > 2. In particular, assuming that the effective radial potential is characterized by a short-range infinitely repulsive core of radius R, we derive a compact analytical formula for the threshold energy E{sub l}{sup max} = E{sub l}{sup max}(n, β{sub n}, R), which characterizes the most weakly bound-state resonance (the most excited energy level) of the quantum system. (orig.)

Excitation of giant resonances through inelastic scattering of 170 at 84 MeV/u. Fission decay of giant resonances

International Nuclear Information System (INIS)

Cabot, C.; Barrette, J.; Mark, S.K.; Turcotte, R.; Xing, J.; Van der Woude, A.; Van Den Berg, A. M.

1991-01-01

Inelastic scattering of 84 MeV/u 17 0 projectiles have been used to excite the giant resonances (GR) in various nuclei ranging from A=60 to A=232. For the isoscalar giant quadrupole resonance (ISGQR), the energy and width of the resonance, as well as the EWSR obtained from the measured cross sections, are in agreement with the known systematics for A>40. The observed GMR strengths are close to 100% EWRS and are consistent with other recent experimental results using heavy ion projectiles. These results lead to a somewhat different picture than that provided by previous studies using light projectiles. Strength is also observed at high excitation energy. The analysis of these resonances is in progress. Our study of the fission decay of GR in 232 Th leads to a somewhat different conclusion than previously deduced from data obtained with light ion projectiles, where no evidence for the fission decay of the ISGQR has been found. In the present work, due to the very good peak-to-continuum ratio, a structure is observed in the fission coincidence spectrum around 10 MeV which can be attributed to the fission decay of giant resonances. The measured fission probability is consistent with a statistical decay of the ISGQR. 10 figs

Surface-enhanced Raman scattering (SERS) of riboflavin on nanostructured Ag surfaces: The role of excitation wavelength, plasmon resonance and molecular resonance

Science.gov (United States)

Šubr, Martin; Kuzminova, Anna; Kylián, Ondřej; Procházka, Marek

2018-05-01

Optimization of surface-enhanced Raman scattering (SERS)-based sensors for (bio)analytical applications has received much attention in recent years. For optimum sensitivity, both the nanostructure fabrication process and the choice of the excitation wavelength used with respect to the specific analyte studied are of crucial importance. In this contribution, detailed SERS intensity profiles were measured using gradient nanostructures with the localized surface-plasmon resonance (LSPR) condition varying across the sample length and using riboflavin as the model biomolecule. Three different excitation wavelengths (633 nm, 515 nm and 488 nm) corresponding to non-resonance, pre-resonance and resonance excitation with respect to the studied molecule, respectively, were tested. Results were interpreted in terms of a superposition of the enhancement provided by the electromagnetic mechanism and intrinsic properties of the SERS probe molecule. The first effect was dictated mainly by the degree of spectral overlap between the LSPR band, the excitation wavelength along with the scattering cross-section of the nanostructures, while the latter was influenced by the position of the molecular resonance with respect to the excitation wavelength. Our experimental findings contribute to a better understanding of the SERS enhancement mechanism.

Artificial excitation of ELF waves with frequency of Schumann resonance

Science.gov (United States)

Streltsov, A. V.; Guido, T.; Tulegenov, B.; Labenski, J.; Chang, C.-L.

2014-11-01

We report results from the experiment aimed at the artificial excitation of extremely low-frequency (ELF) electromagnetic waves with frequencies corresponding to the frequency of Schumann resonance. Electromagnetic waves with these frequencies can form a standing pattern inside the spherical cavity formed by the surface of the Earth and the ionosphere. In the experiment the ELF waves were excited by heating the ionosphere with X-mode HF electromagnetic waves generated at the High Frequency Active Auroral Research Program (HAARP) facility in Alaska. The experiment demonstrates that heating of the ionosphere can excite relatively large-amplitude electromagnetic waves with frequencies in the range 7.8-8.0 Hz when the ionosphere has a strong F layer, the frequency of the HF radiation is in the range 3.20-4.57 MHz, and the electric field greater than 5 mV/m is present in the ionosphere.

Excitation of multiphase waves of the nonlinear Schroedinger equation by capture into resonances

International Nuclear Information System (INIS)

Friedland, L.; Shagalov, A.G.

2005-01-01

A method for adiabatic excitation and control of multiphase (N-band) waves of the periodic nonlinear Schroedinger (NLS) equation is developed. The approach is based on capturing the system into successive resonances with external, small amplitude plane waves having slowly varying frequencies. The excitation proceeds from zero and develops in stages, as an (N+1)-band (N=0,1,2,...), growing amplitude wave is formed in the (N+1)th stage from an N-band solution excited in the preceding stage. The method is illustrated in simulations, where the excited multiphase waves are analyzed via the spectral approach of the inverse scattering transform method. The theory of excitation of 0- and 1-band NLS solutions by capture into resonances is developed on the basis of a weakly nonlinear version of Whitham's averaged variational principle. The phenomenon of thresholds on the driving amplitudes for capture into successive resonances and the stability of driven, phase-locked solutions in these cases are discussed

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

Electromagnetic excitation of the two-phonon giant dipole resonance

International Nuclear Information System (INIS)

Emling, H.

1994-03-01

It is the aim of this article to summarize our present knowledge on the double isovector giant dipole resonance (DGDR) and our understanding of the electromagnetic excitation mechanism in heavy ion collisions in the relativistic energy regime. In the following chapter, a brief resume on the history of giant resonances is given and, based on their understanding, conclusions on the expected properties of multi-phonon resonances are drawn. In chapter 2, the essential features of electromagnetic heavy ion interactions at (near) relativistic velocities will be illuminated and the theoretical framework is presented, which describes such processes. New experimental methods were required for an appropriate study of Coulomb dissociation processes, which are discussed in chapter 3 together with the experimental results. Chapter 4 is dedicated to summarize the results from electromagnetic excitation studies, to compare with those from alternative methods and, in particular, to contrast experimental findings with theoretical predictions and to address open problems. (orig.)

Teetering Stars: Resonant Excitation of Stellar Obliquities by Hot and Warm Jupiters with External Companions

Science.gov (United States)

Anderson, Kassandra; Lai, Dong

2018-04-01

Stellar spin-orbit misalignments (obliquities) in hot Jupiter systems have been extensively probed in recent years thanks to Rossiter-McLaughlin observations. Such obliquities may reveal clues about hot Jupiter dynamical and migration histories. Common explanations for generating stellar obliquities include high-eccentricity migration, or primordial disk misalignment. This talk investigates another mechanism for producing stellar spin-orbit misalignments in systems hosting a close-in giant planet with an external, inclined planetary companion. Spin-orbit misalignment may be excited due to a secular resonance, occurring when the precession rate of the stellar spin axis (due to the inner orbit) becomes comparable to the precession rate of the inner orbital axis (due to the outer companion). Due to the spin-down of the host star via magnetic braking, this resonance may be achieved at some point during the star's main sequence lifetime for a wide range of giant planet masses and orbital architectures. We focus on both hot Jupiters (with orbital periods less than ten days) and warm Jupiters (with orbital periods around tens of days), and identify the outer perburber properties needed to generate substantial obliquities via resonant excitation, in terms of mass, separation, and inclination. For hot Jupiters, the stellar spin axis is strongly coupled to the orbital axis, and resonant excitation of obliquity requires a close perturber, located within 1-2 AU. For warm Jupiters, the spin and orbital axes are more weakly coupled, and the resonance may be achieved for more distant perturbers (at several to tens of AU). Resonant excitation of the stellar obliquity is accompanied by a decrease in the planets' mutual orbital inclination, and can thus erase high mutual inclinations in two-planet systems. Since many warm Jupiters are known to have outer planetary companions at several AU or beyond, stellar obliquities in warm Jupiter systems may be common, regardless of the

Lifetime-vibrational interference effects in resonantly excited x-ray emission spectra of CO

Energy Technology Data Exchange (ETDEWEB)

Skytt, P.; Glans, P.; Gunnelin, K. [Uppsala Univ. (Sweden)] [and others

1997-04-01

The parity selection rule for resonant X-ray emission as demonstrated for O{sub 2} and N{sub 2} can be seen as an effect of interference between coherently excited degenerate localized core states. One system where the core state degeneracy is not exact but somewhat lifted was previously studied at ALS, namely the resonant X-ray emission of amino-substituted benzene (aniline). It was shown that the X-ray fluorescence spectrum resulting from excitation of the C1s at the site of the {open_quotes}aminocarbon{close_quotes} could be described in a picture separating the excitation and the emission processes, whereas the spectrum corresponding to the quasi-degenerate carbons could not. Thus, in this case it was necessary to take interference effects between the quasi-degenerate intermediate core excited states into account in order to obtain agreement between calculations and experiment. The different vibrational levels of core excited states in molecules have energy splittings which are of the same order of magnitude as the natural lifetime broadening of core excitations in the soft X-ray range. Therefore, lifetime-vibrational interference effects are likely to appear and influence the band shapes in resonant X-ray emission spectra. Lifetime-vibrational interference has been studied in non-resonant X-ray emission, and in Auger spectra. In this report the authors discuss results of selectively excited soft X-ray fluorescence spectra of molecules, where they focus on lifetime-interference effects appearing in the band shapes.

El strength function at high spin and excitation energy

International Nuclear Information System (INIS)

Barrette, J.

1983-04-01

Recently giant dipole resonance-like concentration of the dipole strength function in nuclei was observed at both high excitation energies and high spins. This observation raises the possibility of obtaining new information on the shape of rapidly rotating heated nuclei. Recent experimental results on this subject are reviewed

Dependence of excitation frequency of resonant circuit on RF irradiation position of MRI equipment

International Nuclear Information System (INIS)

Shimizu, Masato; Yamada, Tsutomu; Takemura, Yasushi; Niwa, Touru; Inoue, Tomio

2010-01-01

Hyperthermia using implants is a cancer treatment in which cancer tissue is heated to over 42.5 deg C to selectively kill the cancer cells. In this study, a resonant circuit was used as an implant, and a weak magnetic field of radiofrequency (RF) pulses from a magnetic resonance imaging (MRI) device was used as an excitation source. We report here how the temperature of the resonant circuit was controlled by changing the excitation frequency of the MRI. As a result, the temperature rise of the resonant circuit was successfully found to depend on its position in the MRI device. This significant result indicates that the temperature of the resonant circuit can be controlled only by adjusting the excitation position. Accurate temperature control is therefore expected to be possible by combining this control technique with the temperature measurement function of MRI equipment. (author)

Excitation power quantities in phase resonance testing of nonlinear systems with phase-locked-loop excitation

Science.gov (United States)

Peter, Simon; Leine, Remco I.

2017-11-01

Phase resonance testing is one method for the experimental extraction of nonlinear normal modes. This paper proposes a novel method for nonlinear phase resonance testing. Firstly, the issue of appropriate excitation is approached on the basis of excitation power considerations. Therefore, power quantities known from nonlinear systems theory in electrical engineering are transferred to nonlinear structural dynamics applications. A new power-based nonlinear mode indicator function is derived, which is generally applicable, reliable and easy to implement in experiments. Secondly, the tuning of the excitation phase is automated by the use of a Phase-Locked-Loop controller. This method provides a very user-friendly and fast way for obtaining the backbone curve. Furthermore, the method allows to exploit specific advantages of phase control such as the robustness for lightly damped systems and the stabilization of unstable branches of the frequency response. The reduced tuning time for the excitation makes the commonly used free-decay measurements for the extraction of backbone curves unnecessary. Instead, steady-state measurements for every point of the curve are obtained. In conjunction with the new mode indicator function, the correlation of every measured point with the associated nonlinear normal mode of the underlying conservative system can be evaluated. Moreover, it is shown that the analysis of the excitation power helps to locate sources of inaccuracies in the force appropriation process. The method is illustrated by a numerical example and its functionality in experiments is demonstrated on a benchmark beam structure.

Charge transfer and excitation in high-energy ion-atom collisions

International Nuclear Information System (INIS)

Schlachter, A.S.; Berkner, K.H.; McDonald, R.J.

1986-11-01

Coincidence measurements of charge transfer and simultaneous projectile electron excitation provide insight into correlated two-electron processes in energetic ion-atom collisions. Projectile excitation and electron capture can occur simultaneously in a collision of a highly charged ion with a target atom; this process is called resonant transfer and excitation (RTE). The intermediate excited state which is thus formed can subsequently decay by photon emission or by Auger-electron emission. Results are shown for RTE in both the K shell of Ca ions and the L shell of Nb ions, for simultaneous projectile electron loss and excitation, and for the effect of RTE on electron capture

Resonant and nonresonant transfer and excitation in Si11+ + He collisions

International Nuclear Information System (INIS)

Clark, M.W.

1988-01-01

For many years now, dielectronic recombination (DR) has been discussed as a possible energy loss mechanism in high temperature plasmas (e.g. stars). The process is basically the inverse Auger process and involves the capture of a free electron by an ion and the simultaneous excitation of an inner shell electron of the ion producing a doubly excited state. The DR process also includes the radiative deexcitation of the ion and hence represents an energy loss from the plasma since the plasma is essentially transparent to the photons. If, instead of a free electron, an electron that is weakly bound to an atom is captured and an inner shell electron of the ion is excited, the same excited states are produced as in DR. Because the bound electrons have a momentum distribution (Compton profile), individual doubly excited states cannot, in general, be observed in this case. This new process has been called Resonant Transfer and Excitation (RTE). There is also a competing mechanism for RTE in which excitation occurs via the interaction between a projectile ion electron and a target nucleus and the capture occurs because of the interaction of the projectile nucleus and a target electron. This competing mechanism has been termed Nonresonant Transfer and Excitation (NTE) Measurements have been performed to measure RTE and NTE cross sections. A discussion of the theory, methods, and results is included

Shear Alfven wave excitation by direct antenna coupling and fast wave resonant mode conversion

International Nuclear Information System (INIS)

Borg, G.G.

1994-01-01

Antenna coupling to the shear Alfven wave by both direct excitation and fast wave resonant mode conversion is modelled analytically for a plasma with a one dimensional linear density gradient. We demonstrate the existence of a shear Alfven mode excited directly by the antenna. For localised antennas, this mode propagates as a guided beam along the steady magnetic field lines intersecting the antenna. Shear Alfven wave excitation by resonant mode conversion of a fast wave near the Alfven resonance layer is also demonstrated and we prove that energy is conserved in this process. We compare the efficiency of these two mechanisms of shear Alfven wave excitation and present a simple analytical formula giving the ratio of the coupled powers. Finally, we discuss the interpretation of some experimental results. 45 refs., 7 figs

Resonant Electron capture for be-like ions with K- and L- shell excitations

International Nuclear Information System (INIS)

Hanafy, H.

2005-01-01

Resonant electron capture in electron-ion collisions is known as dielectronic recombination (DR). It was proved that, DR dominants usually over radiative recombination (RR) at high energy. Since 1980's, DR is considered a very important process in thermal plasma. The DR is an effective process in self-cooling and ionization balance as well as plasma modeling. Experimental works are still carried out to understand the trends of DR process. In the present work, DR cross sections are calculated for Be-like ions with K- and L- shell excitations. It is found that, DR cross sections increase as the effective charge (Zeff) increases for both types of excitations. DR rates coefficient in case of L-shell excitation is found to be five times larger than that of K-shell excitation

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.

Observation of high-lying resonances in the H- ion

International Nuclear Information System (INIS)

Harris, P.G.; New Mexico Univ., Albuquerque, NM

1990-05-01

This dissertation reports the observation of several series of resonances, for which both electrons are in excited states, in the photodetachment cross section of H - . These 1 P doubly-excited states interfere with the continuum in which they are embedded, and appear as dips in the production cross section of excited neutral hydrogen. The experiment was performed by intersecting an 800 MeV H - beam with a (266 nm) laser beam at varying angles; the relativistic Doppler shift then ''tuned'' the photon energy in the barycentric frame. The process was observed by using a magnet strong enough the strip the electrons from the excited hydrogen atoms in selected states n and detecting the resulting protons, which allowed the isolation of the individual n channels. Three resonances are clearly visible in each channel. The data support recent theoretical calculations for the positions of doubly-excited 1 P resonances, and verify a new Rydberg-like formula for the modified Coulomb potential

Excitation of density waves at the Lindblad and corotation resonances by an external potential

International Nuclear Information System (INIS)

Goldreich, P.; Tremaine, S.

1979-01-01

We calculate the linear response of a differentially rotating two-dimensional gas disk to a rigidly rotating external potential. The main assumptions are that the sound speed is much smaller than the orbital velocity and that the external potential varies on the scale of the disk radius. We investigate disks both with and without self-gravity.The external potential exerts torques on the disk only at the Lindblad and corotation resonances. The torque is positive at the outer Lindblad resonance and negative at the inner Lindblad resonance; at corotation the torque has the sign of the radial gradient of vorticity per unit surface density. The torques are of the same order of magnitude at both types of resonance and are independent of the sound speed in the disk.The external potential also excites density waves in the vicinity of the Lindblad and corotation resonances. The long trailing wave is excited at a Lindblad resonance. It transports away from the resonance all of the angular momentum which is deposited there by the external torque. Short trailing waves are excited at the corotation resonance. The amplitudes of the excited waves are the same on both sides of the resonance and are small unless the disk is almost gravitationally unstable. No net angular momentum is transported away from the corotation region by the waves. Thus the angular momentum deposited there by the external torque accumulates in the gas.We briefly discuss the behavior of particle disks and prove that the external torques on particle disks are identical to those on gas disks

Shear force distance control in a scanning near-field optical microscope: in resonance excitation of the fiber probe versus out of resonance excitation

International Nuclear Information System (INIS)

Lapshin, D.A.; Letokhov, V.S.; Shubeita, G.T.; Sekatskii, S.K.; Dietler, G.

2004-01-01

The experimental results of the direct measurement of the absolute value of interaction force between the fiber probe of a scanning near-field optical microscope (SNOM) operated in shear force mode and a sample, which were performed using combined SNOM-atomic force microscope setup, are discussed for the out-of-resonance fiber probe excitation mode. We demonstrate that the value of the tapping component of the total force for this mode at typical dither amplitudes is of the order of 10 nN and thus is quite comparable with the value of this force for in resonance fiber probe excitation mode. It is also shown that for all modes this force component is essentially smaller than the usually neglected static attraction force, which is of the order of 200 nN. The true contact nature of the tip-sample interaction during the out of resonance mode is proven. From this, we conclude that such a detection mode is very promising for operation in liquids, where other modes encounter great difficulties

Coherent vs Incoherent Emission from Semiconductor Structures after Resonant Femtosecond Excitation

Science.gov (United States)

Gurioli, Massimo; Bogani, Franco; Ceccherini, Simone; Colocci, Marcello

1997-04-01

We show that an interferometric correlation measurement with fs time resolution provides an unambiguous discrimination between coherent and incoherent emission after resonant femtosecond excitation. The experiment directly probes the most important difference between the two emissions, that is, the phase correlation with the excitation pulse. The comparison with cw frequency resolved measurements demonstrates that the relationship between coherent and incoherent emission is similar under femtosecond and steady-state excitation.

Design of high power solid-state pulsed laser resonators

International Nuclear Information System (INIS)

Narro, R.; Ponce, L.; Arronte, M.

2009-01-01

Methods and configurations for the design of high power solid-state pulsed laser resonators, operating in free running, are presented. For fundamental mode high power resonators, a method is proposed for the design of a resonator with joined stability zones. In the case of multimode resonators, two configurations are introduced for maximizing the laser overall efficiency due to the compensation of the astigmatism induced by the excitation. The first configuration consists in a triangular ring resonator. The results for this configuration are discussed theoretically, showing that it is possible to compensate the astigmatism of the thermal lens virtually in a 100%; however this is only possible for a specific pumping power. The second configuration proposes a dual-active medium resonator, rotated 90 degree one from the other around the optical axis, where each active medium acts as an astigmatic lens of the same dioptric power. The reliability of this configuration is corroborated experimentally using a Nd:YAG dual-active medium resonator. It is found that in the pumping power range where the astigmatism compensation is possible, the overall efficiency is constant, even when increasing the excitation power with the consequent increase of the thermal lens dioptric power. (Author)

Coupling of high-quality-factor optical resonators

International Nuclear Information System (INIS)

Salzenstein, Patrice; Henriet, Rémi; Coillet, Aurélien; Chembo, Yanne K; Mortier, Michel; Sérier-Brault, Hélène; Rasoloniaina, Alphonse; Dumeige, Yannick; Féron, Patrice

2013-01-01

We improve theoretically and experimentally the problem of the coupling between a high Q-factor resonator and its external coupler. We have observed oscillations of ringing induced by the sweeping of the excitation frequency of an active microsphere. Thanks to this approach, the quality factor of an optical resonator was measured and we obtained Q = 5.8 × 10 8 . (paper)

Spin-Orbital Excitations in Ca2RuO4 Revealed by Resonant Inelastic X-Ray Scattering

DEFF Research Database (Denmark)

Das, L.; Forte, F.; Fittipaldi, R.

2018-01-01

The strongly correlated insulator Ca2RuO4 is considered as a paradigmatic realization of both spin-orbital physics and a band-Mott insulating phase, characterized by orbitally selective coexistence of a band and a Mott gap. We present a high resolution oxygen K-edge resonant inelastic x-ray scatt......-Mott scenario. The high-energy excitations correspond to intra-atomic singlet-triplet transitions at an energy scale set by Hund's coupling. Our findings give a unifying picture of the spin and orbital excitations in the band-Mott insulator Ca2RuO4.......The strongly correlated insulator Ca2RuO4 is considered as a paradigmatic realization of both spin-orbital physics and a band-Mott insulating phase, characterized by orbitally selective coexistence of a band and a Mott gap. We present a high resolution oxygen K-edge resonant inelastic x......-ray scattering study of the antiferromagnetic Mott insulating state of Ca2RuO4. A set of low-energy (about 80 and 400 meV) and high-energy (about 1.3 and 2.2 eV) excitations are reported, which show strong incident light polarization dependence. Our results strongly support a spin-orbit coupled band...

The isovector quadrupole resonance in yttrium excited by neutron radiative capture

International Nuclear Information System (INIS)

Zorro, R.; Bergqvist, I.

1987-01-01

In order to investigate the properties of the isovector giant quadrupole resonance (ΔT=1, ΔS=0) in the A=90 mass region, gamma-ray spectra from the reaction 89 Y(n,γ) 90 Y were recorded at several neutron energies in the energy range 12 to 27 MeV at 55 0 , 90 0 and 125 0 . The measured fore-aft asymmetry for the ground-state transition is very small in the low-energy region, but becomes appreciable above a neutron energy of 18 MeV. The observed asymmetry is attributed to interference between radiation from the isovector giant quadrupole resonance and radiation of opposite parity (from the high-energy tail of the giant dipole resonance and direct E1 capture). The data obtained in the present work, interpreted in terms of the direct-semidirect capture model, indicate that the excitation energy of the isovector E2 resonance in 90 Y is 26 ± 1 MeV. The data are consistent with a resonance width of 10 ± 2 MeV and with complete exhaustion of the energy-weighted sum rule for the lower isospin component of the resonance. (orig.)

Resonant excitation of uranium atoms by an argon ion laser

Energy Technology Data Exchange (ETDEWEB)

Maeyama, H; Morikawa, M; Aihara, Y; Mochizuki, T; Yamanaka, C [Osaka Univ. (Japan)

1979-03-01

Photoionization of uranium atoms by UV lines, 3511 A and 3345 A, of an argon ion laser was observed and attributed due to resonant two-photon ionization. The dependence of the photoion currents on laser power was measured in focusing and non-focusing modes of laser beam, which has enabled us to obtain an absorption cross section and an ionization cross section independently. The orders of magnitude of these cross sections averaged over the fine structure were determined to be 10/sup -14/ cm/sup 2/ and 10/sup -17/ cm/sup 2/ respectively from a rate equation model. Resonance between 3511-A laser line and the absorption line of uranium isotopes was also confirmed by the ionization spectra obtained by near-single-frequency operation of the ion laser, which allowed the isotopic selective excitation of the uranium atoms. The maximum value of the enrichment of /sup 235/U was about 14%. The isotope separation of uranium atoms by this resonant excitation has been discussed.

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

Magnetic resonance described in the excitation dependent rotating frame of reference.

Science.gov (United States)

Tahayori, Bahman; Johnston, Leigh A; Mareels, Iven M Y; Farrell, Peter M

2008-01-01

An excitation dependent rotating frame of reference to observe the magnetic resonance phenomenon is introduced in this paper that, to the best of our knowledge, has not been used previously in the nuclear magnetic resonance context. The mathematical framework for this new rotating frame of reference is presented based on time scaling the Bloch equation after transformation to the classical rotating frame of reference whose transverse plane is rotating at the Larmor frequency. To this end, the Bloch equation is rewritten in terms of a magnetisation vector observed from the excitation dependent rotating frame of reference. The resultant Bloch equation is referred to as the time scaled Bloch equation. In the excitation dependent rotating frame of reference whose coordinates are rotating at the instantaneous Rabi frequency the observed magnetisation vector is a much slower signal than the true magnetisation in the rotating frame of reference. As a result the ordinary differential equation solvers have the ability to solve the time scaled version of the Bloch equation with a larger step size resulting in a smaller number of samples for solving the equation to a desired level of accuracy. The simulation results for different types of excitation are presented in this paper. This method may be used in true Bloch simulators in order to reduce the simulation time or increase the accuracy of the numerical solution. Moreover, the time scaled Bloch equation may be employed to determine the optimal excitation pattern in magnetic resonance imaging as well as designing pulses with better slice selectivity which is an active area of research in this field.

On resonance processes in near threshold excitation of resonance lines of Zn+ ion at electron-ion collisions

International Nuclear Information System (INIS)

Imre, A.I.; Gomonaj, A.N.; Vukstich, V.S.; Nemet, A.N.

1998-01-01

The results of spectroscopic investigation of resonances in excitation of near threshold region of separate components of resonance doublet 4p 2 P 1/2,3/2 0 of Zn + ion by electron impact are given in the present work. The physical basis of their production nature is suggested

Wake-Field Wave Resonant Excitation in Magnetized Plasmas by Electromagnetic Pulse

International Nuclear Information System (INIS)

Milant'ev, V.P.; Turikov, V.A.

2006-01-01

In this paper the space charge wave excitation process at electromagnetic pulse propagation along external magnetic field in vicinity of electron cyclotron resonance. In hydrodynamic approach it is obtained an equation for plasma density under ponderomotive force action. With help of this equation we investigated a wake-field wave amplitude dependence from resonance detuning. The numerical simulation using a PIC method electromagnetic pulse propagation process in the resonant conditions was done

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

Excitation-energy-dependent resonances in x-ray emissions under near-threshold electron excitation of the Ce 3d and 4d levels

International Nuclear Information System (INIS)

Chamberlain, M.B.; Baun, W.L.

1975-01-01

Soft x-ray appearance potential spectra of the 3d and 4d levels of polycrystalline cerium metal are reported in this paper. Resonant x-ray emissions are observed when the electron-excitation energy sweeps through the ionization energies of the 3d and 4d levels. The resonant x rays excited at the 3d-level onsets are considerably more intense, and are excited at a lower electron-excitation energy than the 3d-series characteristic x rays. In the neighborhood of the 4d-electron thresholds, four line-like structures extend to approx.8 eV below the 4d-electron binding energies, while two broad and more intense structures occur above the 4d onsets, with the largest one reaching a peak intensity at 12 eV above the 4d thresholds. The resonant emissions apparently arise from the decay of threshold-excited states which are bound to the inner vacancy and have core configurations nd 9 4f 3 , (n=3,4). The exchange interaction between the three 4f electrons and the respective d-orbital vacancy spreads the 4d-threshold structures over a 20 eV range of excitation energies and the 3d-threshold structures over a much smaller range

In situ detection of atomic and molecular iodine using Resonance and Off-Resonance Fluorescence by Lamp Excitation: ROFLEX

Directory of Open Access Journals (Sweden)

J. C. Gómez Martín

2011-01-01

Full Text Available We demonstrate a new instrument for in situ detection of atmospheric iodine atoms and molecules based on atomic and molecular resonance and off-resonance ultraviolet fluorescence excited by lamp emission. The instrument combines the robustness, light weight, low power consumption and efficient excitation of radio-frequency discharge light sources with the high sensitivity of the photon counting technique. Calibration of I₂ fluorescence is achieved via quantitative detection of the molecule by Incoherent Broad Band Cavity-enhanced Absorption Spectroscopy. Atomic iodine fluorescence signal is calibrated by controlled broad band photolysis of known I₂ concentrations in the visible spectral range at atmospheric pressure. The instrument has been optimised in laboratory experiments to reach detection limits of 1.2 pptv for I atoms and 13 pptv for I₂, for S/N = 1 and 10 min of integration time. The ROFLEX system has been deployed in a field campaign in northern Spain, representing the first concurrent observation of ambient mixing ratios of iodine atoms and molecules in the 1–350 pptv range.

Red-excitation resonance Raman analysis of the nu(Fe=O) mode of ferryl-oxo hemoproteins.

Science.gov (United States)

Ikemura, Kenichiro; Mukai, Masahiro; Shimada, Hideo; Tsukihara, Tomitake; Yamaguchi, Satoru; Shinzawa-Itoh, Kyoko; Yoshikawa, Shinya; Ogura, Takashi

2008-11-05

The Raman excitation profile of the nuFe O mode of horseradish peroxidase compound II exhibits a maximum at 580 nm. This maximum is located within an absorption band with a shoulder assignable to an oxygen-to-iron charge transfer band on the longer wavelength side of the alpha-band. Resonance Raman bands of the nuFe O mode of various ferryl-oxo type hemoproteins measured at 590 nm excitation indicate that many hemoproteins in the ferryl-oxo state have an oxygen-to-iron charge transfer band in the visible region. Since this red-excited resonance Raman technique causes much less photochemical damage in the proteins relative to blue-excited resonance Raman spectroscopy, it produces a higher signal-to-noise ratio and thus represents a powerful tool for investigations of ferryl-oxo intermediates of hemoproteins.

Excitation of giant resonances in 20Ne + 90Zr and 208Pb inelastic scattering at 40 MeV/u1

International Nuclear Information System (INIS)

Suomijaervi, T.; Beaumel, D.; Blumenfeld, Y.; Chomaz, P.; Frascaria, N.; Garron, J.P.; Jacmart, J.C.; Roynette, J.C.; Kraus, L.; Link, I.

1988-01-01

The giant resonance region in the inelastic spectra from the reactions 20 Ne + 90 Zr and 20 Ne + 208 Pb at 40 MeV/nucleon has been studied with a good energy and angular resolutions. The strength distributions of the different multipolarities contributing to the cross section were obtained by a resonance shape independent analysis. In the case of 208 Pb the GDR strength was found to be strongly shifted towards lower excitation energies which can be explained by the exponentially decreasing Coulomb excitation probability. Furthermore, indications for a high multipolarity component in the resonance structure were found in both reactions

Stochastic resonance and vibrational resonance in an excitable system: The golden mean barrier

International Nuclear Information System (INIS)

Stan, Cristina; Cristescu, C.P.; Alexandroaei, D.; Agop, M.

2009-01-01

We report on stochastic resonance and vibrational resonance in an electric charge double layer configuration as usually found in electrical discharges, biological cell membranes, chemical systems and nanostructures. The experiment and numerical computation show the existence of a barrier expressible in terms of the golden mean above which the two phenomena do not take place. We consider this as new evidence for the importance of the golden mean criticality in the oscillatory dynamics, in agreement with El Naschie's E-infinity theory. In our experiment, the dynamics of a charge double layer generated in the inter-anode space of a twin electrical discharge is investigated under noise-harmonic and harmonic-harmonic perturbations. In the first case, a Gaussian noise can enhance the response of the system to a weak injected periodic signal, a clear mark of stochastic resonance. In the second case, similar enhancement can appear if the noise is replaced by a harmonic perturbation with a frequency much higher than the frequency of the weak oscillation. The amplitude of the low frequency oscillation shows a maximum versus the amplitude of the high frequency perturbation demonstrating vibrational resonance. In order to model these dynamics, we derived an excitable system by modifying a biased van der Pol oscillator. The computational study considers the behaviour of this system under the same types of perturbation as in the experimental investigations and is found to give consistent results in both situations.

Excitation dependence of resonance line self-broadening at different atomic densities

OpenAIRE

Li, Hebin; Sautenkov, Vladimir A.; Rostovtsev, Yuri V.; Scully, Marlan O.

2009-01-01

We study the dipole-dipole spectral broadening of a resonance line at high atomic densities when the self-broadening dominates. The selective reflection spectrum of a weak probe beam from the interface of the cell window and rubidium vapor are recorded in the presence of a far-detuned pump beam. The excitation due to the pump reduces the self-broadening. We found that the self-broadening reduction dependence on the pump power is atomic density independent. These results provide experimental e...

Time-resolved resonance raman spectrum of all-trans-diphenylbutadiene in the lowest excited singlet state

DEFF Research Database (Denmark)

Wilbrandt, Robert Walter; Jensen, Niels-Henrik; Langkilde, F.W.

1984-01-01

The resonance Raman spectrwn of all-trans-diphenylbutadiene in its lowest excited S1 state excited in resonance with the S1 → Sn absorption band at 650 nm in non-polar solvents is reported. Three vibrational bands at 1572, 1481 and 1165 cm−1 are observed. A possible assignment of the the 1481 cm−...

Nonlinear Response of Vibrational Conveyers with Nonideal Vibration Exciter: Superharmonic and Subharmonic Resonance

Directory of Open Access Journals (Sweden)

H. Bayıroğlu

2012-01-01

Full Text Available Vibrational conveyers with a centrifugal vibration exciter transmit their load based on the jumping method. Common unbalanced-mass driver oscillates the trough. The motion is strictly related to the vibrational parameters. The transition over resonance of a vibratory system, excited by rotating unbalances, is important in terms of the maximum vibrational amplitude produced and the power demand on the drive for the crossover. The mechanical system is driven by the DC motor. In this study, the working ranges of oscillating shaking conveyers with nonideal vibration exciter have been analyzed analytically for superharmonic and subharmonic resonances by the method of multiple scales and numerically. The analytical results obtained in this study agree well with the numerical results.

Resonant Inelastic X-ray Scattering: From band mapping to inter-orbital excitations

International Nuclear Information System (INIS)

Luning, J.; Hague, C.F.

2008-01-01

Resonant inelastic X-ray scattering (also known as resonant X-ray Raman spectroscopy when only valence and conduction states are involved in the final state excitation) has developed into a major tool for understanding the electronic properties of complex materials. Presently it provides access to electron excitations in the few hundred meV range with element and bulk selectivity. Recent progress in X-ray optics and synchrotron radiation engineering have opened up new perspectives for this powerful technique to improve resolving power and efficiency. We briefly present the basics of the method and illustrate its potential with examples chosen from the literature. (authors)

Calculation of gaint Elambda-resonances of high multipolarity in deformed nuclei

International Nuclear Information System (INIS)

Kiselev, M.A.; Malov, L.A.; Nesterenko, V.O.; Solov'ev, V.G.

1978-01-01

High-miltipole ( lambda=4-7 ) single-phonon states and strength functions of Elambda(0sup(+) → lambdasup(π))-transitions from the ground states to the excited Isup(π)K states with I=lambda in deformed nuclei are calculated. Possible existance of high-multipole ( lambda >= 4 ) giant Elambda-resonances is considered. Magnitudes of isoscalar and isovector constants of multipole-multipole interaction, required for a description of phonons as quasiparticles of the phonon model, are discussed. All the calculations have been carried out in the random-phase approximation of the general semimicroscopic approach. There is a tendency towards broadening resonances and shifting the maxima into the region of high excitation energies as lambda increases. Broad isoscalar resonances at energies of 10-17 MeV, 10-25 MeV, 15-25 MeV and 10-40 MeV for lambda=4, 5, 6 and 7 respectively. Isovector resonances at lambda=4, 5, 6 and 7 show up themselves as well sufficiently clearly

Excitation of multipolar surface plasmon resonance in plasmonic nanoparticles by complex accelerating beams

International Nuclear Information System (INIS)

Yang, Yang; Li, Jiafang; Li, Zhi-Yuan; Chen, Yue-Gang

2015-01-01

In this paper, through a vector-spherical harmonics approach, we investigate the optical spectra of plasmonic Au nanoparticles excited by two special accelerating beams: a non-paraxial Airy beam and a Bessel beam. We systematically analyze the impacts of the beam profile, phase, and helical wave front of the electromagnetic fields on the optical spectrum and the excitation of the surface plasmon resonance (SPR). We find that the high-order phase in the Airy beam would result in strong plasmonic oscillations in the optical spectra, while the cone angle and orbital angular momentum carried by the Bessel beam could be employed to engineer the plasmon modes excited in Au nanoparticles. Furthermore, the optical spectrum excited by a combined Airy–Bessel–Gauss beam is discussed. The study could help to deeply explore new ways to manipulate SPR in metal nanoparticles via the wave front engineering of optical beams for enhancing light–matter interaction and optical sensing performance. (paper)

Excitation of multipolar surface plasmon resonance in plasmonic nanoparticles by complex accelerating beams

Science.gov (United States)

Yang, Yang; Li, Jiafang; Li, Zhi-Yuan; Chen, Yue-Gang

2015-07-01

In this paper, through a vector-spherical harmonics approach, we investigate the optical spectra of plasmonic Au nanoparticles excited by two special accelerating beams: a non-paraxial Airy beam and a Bessel beam. We systematically analyze the impacts of the beam profile, phase, and helical wave front of the electromagnetic fields on the optical spectrum and the excitation of the surface plasmon resonance (SPR). We find that the high-order phase in the Airy beam would result in strong plasmonic oscillations in the optical spectra, while the cone angle and orbital angular momentum carried by the Bessel beam could be employed to engineer the plasmon modes excited in Au nanoparticles. Furthermore, the optical spectrum excited by a combined Airy-Bessel-Gauss beam is discussed. The study could help to deeply explore new ways to manipulate SPR in metal nanoparticles via the wave front engineering of optical beams for enhancing light-matter interaction and optical sensing performance.

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

Tuning excitation laser wavelength for secondary resonance in low-intensity phase-selective laser-induced breakdown spectroscopy for in-situ analytical measurement of nanoaerosols

Science.gov (United States)

Xiong, Gang; Li, Shuiqing; Tse, Stephen D.

2018-02-01

In recent years, a novel low-intensity phase-selective laser-induced breakdown spectroscopy (PS-LIBS) technique has been developed for unique elemental-composition identification of aerosolized nanoparticles, where only the solid-phase nanoparticles break down, forming nanoplasmas, without any surrounding gas-phase breakdown. Additional work has demonstrated that PS-LIBS emissions can be greatly enhanced with secondary resonant excitation by matching the excitation laser wavelength with an atomic transition line in the formed nanoplasma, thereby achieving low limits of detection. In this work, a tunable dye laser is employed to investigate the effects of excitation wavelength and irradiance on in-situ PS-LIBS measurements of TiO2 nanoaerosols. The enhancement factor by resonant excitation can be 220 times greater than that for non-resonant cases under similar conditions. Moreover, the emitted spectra are unique for the selected resonant transition lines for a given element, suggesting the potential to make precise phase-selective and analyte-selective measurements of nanoparticles in a multicomponent multiphase system. The enhancement factor by resonant excitation is highly sensitive to excitation laser wavelength, with narrow excitation spectral windows, i.e., 0.012 to 0.023 nm (FWHM, full width at half maximum) for Ti (I) neutral atomic lines, and 0.051 to 0.139 nm (FWHM) for Ti (II) single-ionized atomic lines. Boltzmann analysis of the emission intensities, temporal response of emissions, and emission dependence on excitation irradiance are investigated to understand aspects of the generated nanoplasmas such as temperature, local thermodynamic equilibrium (LTE), and excitation mechanism.

Observation of high-lying resonances in the H sup minus ion

Energy Technology Data Exchange (ETDEWEB)

Harris, P.G. (Los Alamos National Lab., NM (USA) New Mexico Univ., Albuquerque, NM (USA). Dept. of Physics and Astronomy)

1990-05-01

This dissertation reports the observation of several series of resonances, for which both electrons are in excited states, in the photodetachment cross section of H{sup {minus}}. These {sup 1}P doubly-excited states interfere with the continuum in which they are embedded, and appear as dips in the production cross section of excited neutral hydrogen. The experiment was performed by intersecting an 800 MeV H{sup {minus}} beam with a (266 nm) laser beam at varying angles; the relativistic Doppler shift then tuned'' the photon energy in the barycentric frame. The process was observed by using a magnet strong enough the strip the electrons from the excited hydrogen atoms in selected states n and detecting the resulting protons, which allowed the isolation of the individual n channels. Three resonances are clearly visible in each channel. The data support recent theoretical calculations for the positions of doubly-excited {sup 1}P resonances, and verify a new Rydberg-like formula for the modified Coulomb potential.

Thin film characterization by resonantly excited internal standing waves

Energy Technology Data Exchange (ETDEWEB)

Di Fonzio, S [SINCROTRONE TRIESTE, Trieste (Italy)

1996-09-01

This contribution describes how a standing wave excited in a thin film can be used for the characterization of the properties of the film. By means of grazing incidence X-ray reflectometry one can deduce the total film thickness. On the other hand in making use of a strong resonance effect in the electric field intensity distribution inside a thin film on a bulk substrate one can learn more about the internal structure of the film. The profile of the internal standing wave is proven by diffraction experiments. The most appropriate non-destructive technique for the subsequent thin film characterization is angularly dependent X-ray fluorescence analysis. The existence of the resonance makes it a powerful tool for the detection of impurities and of ultra-thin maker layers, for which the position can be determined with very high precision (about 1% of the total film thickness). This latter aspect will be discussed here on samples which had a thin Ti marker layer at different positions in a carbon film. Due to the resonance enhancement it was still possible to perform these experiments with a standard laboratory x-ray tube and with standard laboratory tool for marker or impurity detection in thin films.

Shape resonances and the excitation of helium autoionising states by electrons in the 57-66 eV region

International Nuclear Information System (INIS)

Burgt, P.J.M. van der; Eck, J. van; Heideman, H.G.M.

1986-01-01

Optical excitation functions of singly excited helium states are presented, measured by detecting the yield of emitted photons as a function of the incident electron energy from 56 to 66 eV. Many structures are observed, which are caused by negative-ion resonances and by the decay of autoionising states followed by post-collision interaction. Some of the structures are interpreted as being caused by hitherto unknown shape resonances lying very close to the thresholds of a particular class of autoionising states. As these shape resonances almost exclusively decay to their respective parent (autoionising) states, thereby considerably enhancing the threshold excitation cross sections of these states, they can only be observed via the PCI effect on the excitation functions of (higher lying) singly excited states. Using the recently introduced supermultiplet classification for doubly excited states a selection rule for the near-threshold excitation of doubly excited states by electron impact is deduced from the measurements. Only states with large probabilities in the Wannier region of configuration space (where the two electrons are at nearly equal distances and on opposite sides of the nucleus) are strongly excited. It is pointed out that these states are precisely the states that can support the above mentioned shape resonances at their thresholds. (author)

Direct observation of spin-quadrupolar excitations in Sr2CoGe2O7 by high-field electron spin resonance

Science.gov (United States)

Akaki, Mitsuru; Yoshizawa, Daichi; Okutani, Akira; Kida, Takanori; Romhányi, Judit; Penc, Karlo; Hagiwara, Masayuki

2017-12-01

Exotic spin-multipolar ordering in spin transition metal insulators has so far eluded unambiguous experimental observation. A less studied, but perhaps more feasible fingerprint of multipole character emerges in the excitation spectrum in the form of quadrupolar transitions. Such multipolar excitations are desirable as they can be manipulated with the use of light or electric field and can be captured by means of conventional experimental techniques. Here we study single crystals of multiferroic Sr2CoGe2O7 and observe a two-magnon spin excitation appearing above the saturation magnetic field in electron spin resonance (ESR) spectra. Our analysis of the selection rules reveals that this spin excitation mode does not couple to the magnetic component of the light, but it is excited by the electric field only, in full agreement with the theoretical calculations. Due to the nearly isotropic nature of Sr2CoGe2O7 , we identify this excitation as a purely spin-quadrupolar two-magnon mode.

Highly sensitive high resolution Raman spectroscopy using resonant ionization methods

International Nuclear Information System (INIS)

Owyoung, A.; Esherick, P.

1984-05-01

In recent years, the introduction of stimulated Raman methods has offered orders of magnitude improvement in spectral resolving power for gas phase Raman studies. Nevertheless, the inherent weakness of the Raman process suggests the need for significantly more sensitive techniques in Raman spectroscopy. In this we describe a new approach to this problem. Our new technique, which we call ionization-detected stimulated Raman spectroscopy (IDSRS), combines high-resolution SRS with highly-sensitive resonant laser ionization to achieve an increase in sensitivity of over three orders of magnitude. The excitation/detection process involves three sequential steps: (1) population of a vibrationally excited state via stimulated Raman pumping; (2) selective ionization of the vibrationally excited molecule with a tunable uv source; and (3) collection of the ionized species at biased electrodes where they are detected as current in an external circuit

Role of giant resonance excitation in heavy ion collisions

International Nuclear Information System (INIS)

Catara, F.; Chomaz, Ph.

1987-01-01

In this paper we discuss several aspects of heavy ion collisions involving collective vibrational modes. In our approach the relative motion is treated in a semiclassical approximation, while the intrinsic degrees of freedom are described microscopically within the RPA. The differences with respect to macroscopic models are analyzed in the appendix. First we present some results on the inelastic scattering cross section and we show that the structures observed experimentally can be explained in terms of multiple excitation of the Giant Quadrupole Resonance. After we calculate an adiabatic polarization potential describing the coupling to the collective vibrational modes and show that it produces a strong enhancement of the subbarrier fusion cross section. This enhancement is found to be enough to reproduce the experimental data for symmetric systems, while for asymmetric reactions the coupling to other degrees of freedom, like transfer, is needed. Finally we report some preliminary results on a dynamical calculation of the real and imaginary parts of the polarization potential. We show that at high incident energies (E/A > 20MeV) the role of the Giant Quadrupole Resonance becomes dominant

Time dependence of resonance γ-radiation modulated by acoustic excitations

International Nuclear Information System (INIS)

Mkrtchyan, A.R.; Arakelyan, A.R.; Gabrielyan, R.G.; Kocharyan, L.A.; Grigoryan, G.R.; Slavinskii, M.M.

1984-01-01

Experimental investigations of the time dependence of the γ-resonance absorption line intensity in case of modulation by acoustic waves are presented. 57 Co was used as source and a stainless steel foil was chosen as an absorber. The time dependences of the counting rate of the resonant γ-quanta corresponding to excitations with 3400 Hz and with 1.5 or 7 V at the vibrosystem transducer are plotted. The measurements show that the method has principal advantages over the conventional Moessbauer spectroscopy

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)

Resonant transfer excitation of fluorine-like Mo{sup 33+} ion

Energy Technology Data Exchange (ETDEWEB)

Ramadan, Hassan [Ain Shams Univ., Cairo (Egypt). Dept. of Basic Sciences; Elkilany, Sabbah [Kafr El-sheikh Univ. (Egypt). Dept. of Mathematics

2010-06-15

Dielectronic recombination (DR) cross sections (anti {sigma}{sup DR}) and rate coefficients ({alpha}{sup DR}) for Mo{sup 33+} are calculated using the angular momentum average scheme (AMA). Moreover, the resonant transfer excitation followed by X-ray emission (RTEX) cross sections ({sigma}{sup RTEX}) for the collision of Mo{sup 33+} with H{sub 2} and He targets are calculated and studied. The calculations of the cross sections are performed for both K- and L-shell excitations. A smooth change with the temperatures for {alpha}{sup DR} is found for all kinds of excitations. The rates for K-shell excitation are very small in comparison with the rates for L-shell excitation. The RTEX cross sections for Mo{sup 33+} ions are obtained from their corresponding DR cross sections by the method of folding in the impulse approximation (IMA). {sigma}{sup RTEX} for the K-shell excitation shows two overlapped peaks which may be attributed to the two groups in this excitation process. The present calculations are considered as a database for future comparison with theoretical and experimental data using other coupling schemes. Multiple Auger channels are complicating the dependence of the cross sections on principal quantum numbers. (orig.)

Electron heating via self-excited plasma series resonance in geometrically symmetric multi-frequency capacitive plasmas

International Nuclear Information System (INIS)

Schüngel, E; Brandt, S; Schulze, J; Donkó, Z; Korolov, I; Derzsi, A

2015-01-01

The self-excitation of plasma series resonance (PSR) oscillations plays an important role in the electron heating dynamics in capacitively coupled radio-frequency (CCRF) plasmas. In a combined approach of PIC/MCC simulations and a theoretical model based on an equivalent circuit, we investigate the self-excitation of PSR oscillations and their effect on the electron heating in geometrically symmetric CCRF plasmas driven by multiple consecutive harmonics. The discharge symmetry is controlled via the electrical asymmetry effect (EAE), i.e. by varying the total number of harmonics and tuning the phase shifts between them. It is demonstrated that PSR oscillations will be self-excited under both symmetric and asymmetric conditions, if (i) the charge–voltage relation of the plasma sheaths deviates from a simple quadratic behavior and (ii) the inductance of the plasma bulk exhibits a temporal modulation. These two effects have been neglected up to now, but we show that they must be included in the model in order to properly describe the nonlinear series resonance circuit and reproduce the self-excitation of PSR oscillations, which are observed in the electron current density resulting from simulations of geometrically symmetric CCRF plasmas. Furthermore, the effect of PSR self-excitation on the discharge current and the plasma properties, such as the potential profile, is illustrated by applying Fourier analysis. High-frequency oscillations in the entire spectrum between the applied frequencies and the local electron plasma frequency are observed. As a consequence, the electron heating is strongly enhanced by the presence of PSR oscillations. A complex electron heating dynamics is found during the expansion phase of the sheath, which is fully collapsed, when the PSR is initially self-excited. The nonlinear electron resonance heating (NERH) associated with the PSR oscillations causes a spatial asymmetry in the electron heating. By discussing the resulting ionization

Excitation of large-amplitude parametric resonance by the mechanical stiffness modulation of a microstructure

International Nuclear Information System (INIS)

Krylov, Slava; Gerson, Yuval; Nachmias, Tali; Keren, Uri

2010-01-01

In this work we report on an approach allowing efficient parametric excitation of large-amplitude stable oscillations of a microstructure operated by a parallel-plate electrode, and present results of a theoretical and experimental investigation of the device. The frame-type structure, fabricated from a silicon on insulator (SOI) substrate using deep reactive ion etching (DRIE), consists a pair of cantilever-type suspensions connected at their ends by a link. The time-varying electrostatic force applied to the link by a parallel-plate electrode is transformed into a periodic tension of the beams, resulting in the modulation of their flexural stiffness and consequently the mechanical parametric excitation of the structure. The lateral compliance of the beams allows for large-amplitude in-plane oscillations in the direction parallel to the electrode while high axial stiffness prevents undesirable instabilities. The lumped model of the device, considered as an assembly of geometrically nonlinear massless flexures and a rigid massive link and built using the Rayleigh–Ritz method, predicted the feasibility of the excitation approach. The fabricated devices were operated in ambient air conditions by a combination of a steady (dc) and time-dependent (ac) components of voltage and the large-amplitude responses, up to 75 µm, in the vicinity of the principal parametric and primary resonances were registered by means of video acquisition and image processing. The shapes of the experimental resonant curves were consistent with those predicted by the model. The location and size of the instability regions on the frequency–voltage plane (parametric tongues) were quantitatively in good agrement with the model results. Theoretical and experimental results indicate that the suggested approach can be efficiently used for excitation of various types of microdevices where stable resonant operation combined with robustness and large vibrational amplitudes are desirable

High excitation of the species in nitrogen–aluminum plasma generated by electron cyclotron resonance microwave discharge of N2 gas and pulsed laser ablation of Al target

International Nuclear Information System (INIS)

Liang, Peipei; Li, Yanli; Cai, Hua; You, Qinghu; Yang, Xu; Huang, Feiling; Sun, Jian; Xu, Ning; Wu, Jiada

2014-01-01

A reactive nitrogen–aluminum plasma generated by electron cyclotron resonance (ECR) microwave discharge of N 2 gas and pulsed laser ablation of an Al target is characterized spectroscopically by time-integrated and time-resolved optical emission spectroscopy (OES). The vibrational and rotational temperatures of N 2 species are determined by spectral simulation. The generated plasma strongly emits radiation from a variety of excited species including ambient nitrogen and ablated aluminum and exhibits unique features in optical emission and temperature evolution compared with the plasmas generated by a pure ECR discharge or by the expansion of the ablation plume. The working N 2 gas is first excited by ECR discharge and the excitation of nitrogen is further enhanced due to the fast expansion of the aluminum plume induced by target ablation, while the excitation of the ablated aluminum is prolonged during the plume expansion in the ECR nitrogen plasma, resulting in the formation of strongly reactive nitrogen–aluminum plasma which contains highly excited species with high vibrational and rotational temperatures. The enhanced intensities and the prolonged duration of the optical emissions of the combined plasma would provide an improved analytical capability for spectrochemical analysis. - Highlights: • ECR discharge and pulsed laser ablation generate highly excited ECR–PLA plasma. • The expansion of PLA plasma results in excitation enhancement of ECR plasma species. • The ECR plasma leads to excitation prolongation of PLA plasma species. • The ECR–PLA plasma emits strong emissions from a variety of excited species. • The ECR–PLA plasma maintains high vibrational–rotational temperatures for a long time

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

Direct excitation of resonant torsional Alfven waves by footpoint motions

NARCIS (Netherlands)

Ruderman, M. S.; Berghmans, D.; Goossens, M.; Poedts, S.

1997-01-01

The present paper studies the heating of coronal loops by linear resonant Alfven waves that are excited by the motions of the photospheric footpoints of the magnetic field lines. The analysis is restricted to torsionally polarised footpoint motions in an axially symmetric system so that only

Highly selective population of two excited states in nonresonant two-photon absorption

International Nuclear Information System (INIS)

Zhang Hui; Zhang Shi-An; Sun Zhen-Rong

2011-01-01

A nonresonant two-photon absorption process can be manipulated by tailoring the ultra-short laser pulse. In this paper, we theoretically demonstrate a highly selective population of two excited states in the nonresonant two-photon absorption process by rationally designing a spectral phase distribution. Our results show that one excited state is maximally populated while the other state population is widely tunable from zero to the maximum value. We believe that the theoretical results may play an important role in the selective population of a more complex nonlinear process comprising nonresonant two-photon absorption, such as resonance-mediated (2+1)-three-photon absorption and (2+1)-resonant multiphoton ionization. (atomic and molecular physics)

New results on multiple excitations of giant resonances

International Nuclear Information System (INIS)

Mordechai, S.; Texas Univ., Austin, TX; Moore, C.F.

1993-01-01

Exotic excitations like the double giant dipole were predicted for many years but not observed experimentally until recently. Several experiments have been carried out at Los Alamos National laboratory to search for these new collective modes of the nucleus. The results discover two previously unobserved types of double giant resonances. This work presents the recent pion double charge exchange data and the analysis that support the existence of two such exotic vibrational nuclear modes

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

Nanoantennas for surface enhanced infrared spectroscopy: Effects of interaction and higher order resonant excitations

Directory of Open Access Journals (Sweden)

J. Aizpurua

2011-09-01

Full Text Available The sensitivity in surface enhanced infrared spectroscopy (SEIRS strongly depends on where the resonant excitation is spectrally located compared to the molecular vibration that is to be enhanced. In this contribution, we study the effect of coupling in the electromagnetic properties of 2D gold nanorod arrays in the IR. We also study the SEIRS activity of higher order resonant excitations in long nanoantennas to identify polaritonic signals of a supporting SiO2 layer with nanometer thickness (3 nm on a silicon substrate.

Spin-Orbital Excitations in Ca_{2}RuO_{4} Revealed by Resonant Inelastic X-Ray Scattering

Directory of Open Access Journals (Sweden)

L. Das

2018-03-01

Full Text Available The strongly correlated insulator Ca_{2}RuO_{4} is considered as a paradigmatic realization of both spin-orbital physics and a band-Mott insulating phase, characterized by orbitally selective coexistence of a band and a Mott gap. We present a high resolution oxygen K-edge resonant inelastic x-ray scattering study of the antiferromagnetic Mott insulating state of Ca_{2}RuO_{4}. A set of low-energy (about 80 and 400 meV and high-energy (about 1.3 and 2.2 eV excitations are reported, which show strong incident light polarization dependence. Our results strongly support a spin-orbit coupled band-Mott scenario and explore in detail the nature of its exotic excitations. Guided by theoretical modeling, we interpret the low-energy excitations as a result of composite spin-orbital excitations. Their nature unveils the intricate interplay of crystal-field splitting and spin-orbit coupling in the band-Mott scenario. The high-energy excitations correspond to intra-atomic singlet-triplet transitions at an energy scale set by Hund’s coupling. Our findings give a unifying picture of the spin and orbital excitations in the band-Mott insulator Ca_{2}RuO_{4}.

Resonance charge exchange between excited states in slow proton-hydrogen collisions

International Nuclear Information System (INIS)

Tolstikhina, Inga Yu.; Kato, Daiji

2010-01-01

The theory of resonance charge exchange in slow collisions of a proton with a hydrogen atom in the excited state is developed. It extends the Firsov-Demkov theory of resonance charge exchange to the case of degenerate initial and final states. The theory is illustrated by semiclassical and quantum calculations of charge exchange cross sections between states with n=2 in parabolic and spherical coordinates. The results are compared with existing close-coupling calculations.

Excitation of Ionospheric Alfvén Resonator with HAARP

Science.gov (United States)

Streltsov, A. V.; Chang, C.; Labenski, J.; Milikh, G. M.; Vartanyan, A.; Snyder, A. L.

2011-12-01

We report results from numerical and experimental studies of the excitation of ULF waves inside the ionospheric Alfvén resonator (IAR) by heating the ionosphere with powerful HF waves launched from the High Frequency Active Auroral Research Program (HAARP) facility in Alaska. Numerical simulations of the two-fluid MHD model describing IAR in a dipole magnetic field geometry with plasma parameters taken from the observations at HAARP during October-November 2010 experimental campaign reveal that the IAR quality is higher during night-time conditions, when the ionospheric conductivity is very low. Simulations also reveal that the resonance wave cannot be identified from the magnetic measurements on the ground or at an altitude above 600 km because the magnetic field in this wave has nodes on both ends of the resonator, and the best way to detect IAR modes is by measuring the electric field on low-Earth-orbit satellites. These theoretical predictions are in good, quantitative agreement with results from observations: In particular, 1) observations from the ground-based magnetometer at the HAARP site demonstrate no any significant difference in the amplitudes of the magnetic field generated by HAARP in the frequency range from 0 to 5 Hz, and 2) the DEMETER satellite detected the electric field of the IAR first harmonic at an altitude of 670 km above HAARP during the heating experiment.

Theory of the effect of odd-photon destructive interference on optical shifts in resonantly enhanced multiphoton excitation and ionization

International Nuclear Information System (INIS)

Payne, M.G.; Deng, L.; Garrett, W.R.

1998-01-01

We present a theory for two- and three-photon excitation, optical shifting, and four-wave mixing when a first laser is tuned onto, or near, a two-photon resonance and a second much more intense laser is tuned near or on resonance between the two-photon resonance and a second excited state. When the second excited state has a dipole-allowed transition back to the ground state and the concentration is sufficiently high, a destructive interference is produced between three-photon coupling of the ground state and the second excited state and one-photon coupling between the same states by the internally generated four-wave mixing field. This interference leads to several striking effects. For instance, as the onset of the interference occurs, the optical shifts in the two-photon resonance excitation line shape become smaller in copropagating geometry so that the line shapes for multiphoton ionization enhanced by the two-photon resonance eventually become unaffected by the second laser. In the same range of concentrations the four-wave mixing field evolves to a concentration-independent intensity. With counterpropagating laser beams the line shape exhibits normal optical shifts like those observed for both copropagating and counterpropagating laser beams at very low concentrations. The theoretical work presented here extends our earlier works by including the effect of laser bandwidth and by removing the restriction of having the second laser be tuned far from three-photon resonance. In this way we have now included, as a special case, the effect of both laser bandwidth and interference on laser-induced transparency. Unlike other effects related to odd-photon destructive interference, the effect of a broad bandwidth is to bring about the predicted effects at much lower concentrations. Studies in rubidium show good agreement between theory and experiment for both ionization line shapes and four-wave mixing intensity as a function of concentration. copyright 1998 The

Interaction between 4p photoionization and 3p resonant excitation channels of krypton

International Nuclear Information System (INIS)

Buhr, T.; Kover, A.; Varga, D.; Muller, A.; Ricz, S.; Justus-Liebig- Universitat Giessen, Giessen; Holste, K.; Borovik, Jr.A.A.; Bernhardt, D.; Schippers, S.

2011-01-01

Complete text of publication follows. The angular distribution of Kr 4p photoelectrons was measured employing a linearly polarized photon beam at energies from 205 eV to 230 eV. In this range the Kr 3p→ns/md (n,m=4,5,6, etc.) resonances can be excited. The experimental anisotropy parameters (β, γ and δ) were determined for the Kr 4p shell and its fine structure components. The measurement was carried out at beamline BW3 of the DORIS III synchrotron light source at HASYLAB (Hamburg, Germany). The ESA-22D electrostatic electron spectrometer was used to analyze the emitted electrons. The spectrometer consists of a spherical and a cylindrical mirror analyzer. The spherical mirror focuses the electrons from the scattering plane to the entrance slit of the cylindrical analyzer performing the energy analysis of the electrons. (For detailed description of an ESA- 22-type electron spectrometer see Ref. [1].) The measured dipole anisotropy parameters ? of Kr 4p photoelectrons are shown in Fig. 1 as a function of photon energy. Resonance-like structure can be seen in the photon energy dependence of the dipole parameters. This structure indicates that the channel interactions are important between the 3p resonant excitation-autoionization and 4p direct photoionization processes in krypton. The natural line width of the 3p photoelectron peaks was determined from the measured spectra and it is about 0.8 eV while the experimental width of the resonance near 220 eV photon energy (3p 1/2 -1 →5s resonant excitation) is approximately 2 eV in Fig. 1. This broadening can be explained with the strong interference between the ionization and excitation channels. As before, we conclude that the angular distribution of photoelectrons is strongly influenced by the excitation processes. Acknowledgements. The authors wish to thank the DORIS III staff for providing excellent working conditions. This work was supported by the NKTH-OTKA (Grant No. K67719), and by the European Community

Whole body traveling wave magnetic resonance imaging at high field strength: homogeneity, efficiency, and energy deposition as compared with traditional excitation mechanisms.

Science.gov (United States)

Zhang, Bei; Sodickson, Daniel K; Lattanzi, Riccardo; Duan, Qi; Stoeckel, Bernd; Wiggins, Graham C

2012-04-01

In 7 T traveling wave imaging, waveguide modes supported by the scanner radiofrequency shield are used to excite an MR signal in samples or tissue which may be several meters away from the antenna used to drive radiofrequency power into the system. To explore the potential merits of traveling wave excitation for whole-body imaging at 7 T, we compare numerical simulations of traveling wave and TEM systems, and juxtapose full-wave electrodynamic simulations using a human body model with in vivo human traveling wave imaging at multiple stations covering the entire body. The simulated and in vivo traveling wave results correspond well, with strong signal at the periphery of the body and weak signal deep in the torso. These numerical results also illustrate the complicated wave behavior that emerges when a body is present. The TEM resonator simulation allowed comparison of traveling wave excitation with standard quadrature excitation, showing that while the traveling wave B +1 per unit drive voltage is much less than that of the TEM system, the square of the average B +1 compared to peak specific absorption rate (SAR) values can be comparable in certain imaging planes. Both systems produce highly inhomogeneous excitation of MR signal in the torso, suggesting that B(1) shimming or other parallel transmission methods are necessary for 7 T whole body imaging. Copyright © 2011 Wiley-Liss, Inc.

Quantum resonances in a single plaquette of Josephson junctions: excitations of Rabi oscillations

OpenAIRE

Fistul, M. V.

2001-01-01

We present a theoretical study of a quantum regime of the resistive (whirling) state of dc driven anisotropic single plaquette containing three small Josephson junctions. The current-voltage characteristics of such a system display resonant steps that are due to the resonant interaction between the time dependent Josephson current and the excited electromagnetic oscillations (EOs). The voltage positions of the resonances are determined by the quantum interband transitions of EOs. We show that...

Analysis of asymmetric resonance response of thermally excited silicon micro-cantilevers for mass-sensitive nanoparticle detection

Science.gov (United States)

Bertke, Maik; Hamdana, Gerry; Wu, Wenze; Suryo Wasisto, Hutomo; Uhde, Erik; Peiner, Erwin

2017-06-01

In this paper, the asymmetric resonance frequency (f 0) responses of thermally in-plane excited silicon cantilevers for a pocket-sized, cantilever-based airborne nanoparticle detector (Cantor) are analysed. By measuring the shift of f 0 caused by the deposition of nanoparticles (NPs), the cantilevers are used as a microbalance. The cantilever sensors are low cost manufactured from silicon by bulk-micromachining techniques and contain an integrated p-type heating actuator and a sensing piezoresistive Wheatstone bridge. f 0 is tracked by a homemade phase-locked loop (PPL) for real-time measurements. To optimize the sensor performance, a new cantilever geometry was designed, fabricated and characterized by its frequency responses. The most significant characterisation parameters of our application are f 0 and the quality factor (Q), which have high influences on sensitivity and efficiency of the NP detector. Regarding the asymmetric resonance signal, a novel fitting function based on the Fano resonance replacing the conventionally used function of the simple harmonic oscillator and a method to calculate Q by its fitting parameters were developed for a quantitative evaluation. To obtain a better understanding of the resonance behaviours, we analysed the origin of the asymmetric line shapes. Therefore, we compared the frequency response of the on-chip thermal excitation with an external excitation using an in-plane piezo actuator. In correspondence to the Fano effect, we could reconstruct the measured resonance curves by coupling two signals with constant amplitude and the expected signal of the cantilever, respectively. Moreover, the phase of the measurement signal can be analysed by this method, which is important to understand the locking process of the PLL circuit. Besides the frequency analysis, experimental results and calibration measurements with different particle types are presented. Using the described analysis method, decent results to optimize a next

Multipole giant resonances of 12C nucleus electro excitation in intermediate coupling model

International Nuclear Information System (INIS)

Goncharova, N.G.; Zhivopistsev, F.A.

1977-01-01

Multipole giant resonances in 12 C electroexcitation are considered using the shell model with coupling. Cross sections are calculated for the states of 1 - , 2 - , 3 - , 4 - , at T=1. The distributions of the transverse form factor at transferred momenta equal to q approximately 0.75, 1.04, 1.22 and 1.56 Fm -1 and the longitudinal form factor for q = 0.75, 1.04, 1.56 Fm -1 are presented. For the excitation energies in the range from 18 to 28 MeV positive-parity states have a small contribution in the cross section. The distribution of the total form factor in the excitation energies is given. It is concluded that the multipole giant resonances of anomalous parity levels calculated within the interatomic-coupling shell model show a satisfactorily close agreement with the behavior of experimental form factors in the excitation energy range from 18 to 28 MeV

Resonances in photoionization. Cross section for vibrationally excited H2

International Nuclear Information System (INIS)

Mezei, J.Zs.; Jungen, Ch.

2011-01-01

Complete text of publication follows. Diatomic molecular Hydrogen is the most abundant molecule in interstellar molecular clouds. The modeling of these environments relies on accurate cross sections for the various relevant processes. Among them, the photoionization plays a major role in the kinetics and in the energy exchanges involving H 2 . The recent discovery of vibrationally excited molecular hydrogen in extragalactic environments revealed the need for accurate evaluation of the corresponding photoionization cross sections. In the present work we report theoretical photoionization cross sections for excitation from excited vibrational levels of the ground state, dealing with the Q(N = 1) (ΔN = 0, where N is the total angular momentum of the molecule) transitions which account for roughly one third of the total photoabsorption cross section. We will focus on the v' = 1 excited level of the ground electronic state. Our calculations are based on Multichannel Quantum Defect Theory (MQDT), which allows us to take into account of the full manifold of Rydberg states and their interactions with the electronic continuum. We have carried out two types of MQDT calculations. First, we omitted all open channels and calculated energy levels, wave functions and spontaneous emission Einstein coefficients, making use of the theoretical method presented in [2]. In a second set of calculations we included the open ionization channels in the computations getting the continuum phase shifts, channel mixing coefficients and channel dipole moments and finally the photoabsorption/ photoionization cross section. The cross section is dominated by the presence of resonance structures corresponding to excitation of various vibrational levels of bound electronic states which lie above the ionization threshold. In order to assess the importance of the resonances we have calculated for each vibrational interval (the energy interval between two consecutive ionization thresholds) the

Flexible structured high-frequency film bulk acoustic resonator for flexible wireless electronics

International Nuclear Information System (INIS)

Zhou, Changjian; Shu, Yi; Yang, Yi; Ren, Tian-Ling; Jin, Hao; Dong, Shu-Rong; Chan, Mansun

2015-01-01

Flexible electronics have inspired many novel and very important applications in recent years and various flexible electronic devices such as diodes, transistors, circuits, sensors, and radiofrequency (RF) passive devices including antennas and inductors have been reported. However, the lack of a high-performance RF resonator is one of the key bottlenecks to implement flexible wireless electronics. In this study, for the first time, a novel ultra-flexible structured film bulk acoustic resonator (FBAR) is proposed. The flexible FBAR is fabricated on a flexible polyimide substrate using piezoelectric thin film aluminum nitride (AlN) for acoustic wave excitation. Both the shear wave and longitudinal wave can be excited under the surface interdigital electrodes configuration we proposed. In the case of the thickness extension mode, a flexible resonator with a working frequency as high as of 5.2325 GHz has been realized. The resonators stay fully functional under bending status and after repeated bending and re-flattening operations. This flexible high-frequency resonator will serve as a key building block for the future flexible wireless electronics, greatly expanding the application scope of flexible electronics. (paper)

High Rydberg resonances in dielectronic recombination of pb(79+).

Science.gov (United States)

Brandau, C; Bartsch, T; Hoffknecht, A; Knopp, H; Schippers, S; Shi, W; Müller, A; Grün, N; Scheid, W; Steih, T; Bosch, F; Franzke, B; Kozhuharov, C; Mokler, P H; Nolden, F; Steck, M; Stöhlker, T; Stachura, Z

2002-07-29

Dielectronic recombination resonances of Pb (79+) associated with 2s(1/2)-->2p(1/2) excitations were measured at the heavy-ion storage ring ESR at GSI. The fine structure of the energetically lowest resonance manifold Pb (78+)(1s(2)2p(1/2)20l(j)) at around 18 eV could partially be resolved, and rate coefficients on an absolute scale were obtained. A comparison of the experimental data with results of a fully relativistic theoretical approach shows that high-angular-momentum components up to j=31/2 significantly contribute to the total resonance strength demonstrating the necessity to revise the widespread notion of negligible high-angular-momentum contributions at least for very highly charged ions.

Even-parity resonances with synchrotron radiation from Laser Excited Lithium at 1s^22p State

Science.gov (United States)

Huang, Ming-Tie; Wehlitz, Ralf

2010-03-01

Correlated many-body dynamics is still one of the unsolved fundamental problems in physics. Such correlation effects can be most clearly studied in processes involving single atoms for their simplicity.Lithium, being the simplest open shell atom, has been under a lot of study. Most of the studies focused on ground state lithium. However, only odd parity resonances can be populated through single photon (synchrotron radiation) absorption from ground state lithium (1s^22s). Lithium atoms, after being laser excited to the 1s^22p state, allow the study of even parity resonances. We have measured some of the even parity resonances of lithium for resonant energies below 64 eV. A single-mode diode laser is used to excite lithium from 1s^22s ground state to 1s^22p (^2P3/2) state. Photoions resulting from the interaction between the excited lithium and synchrotron radiation were analyzed and collected by an ion time-of-flight (TOF) spectrometer with a Z- stack channel plate detector. The Li^+ ion yield was recorded while scanning the undulator along with the monochromator. The energy scans have been analyzed regarding resonance energies and parameters of the Fano profiles. Our results for the observed resonances will be presented.

Three-mode resonant coupling of collective excitations in a Bose-Einstein condensate

International Nuclear Information System (INIS)

Ma Yongli; Huang, Guoxiang; Hu Bambi

2005-01-01

We make a systematic study of the resonant mode coupling of the collective excitations at zero temperature in a Bose-Einstein condensate (BEC). (i) Based on the Gross-Pitaevskii equation we derive a set of nonlinearly coupled envelope equations for a three-mode resonant interaction (TMRI) by means of a method of multiple scales. (ii) We calculate the coupling matrix elements for the TMRI and show that the divergence appearing in previous studies can be eliminated completely by using a Fetter-like variational approximation for the ground-state wave function of the condensate. (iii) We provide the selection rules in mode-mode interaction processes [including TMRI and second-harmonic generation (SHG)] according to the symmetry of the excitations. (iv) By solving the nonlinearly coupled envelope equations we obtain divergence-free nonlinear amplitudes for the TMRI and SHG processes and show that our theoretical results on the shape oscillations of the condensate agree well with the experimental ones. We suggest also an experiment to check the theoretical prediction of the present study on the TMRI of collective excitations in a BEC

Shell structure effects at high excitations and many-quasiparticle configurations

International Nuclear Information System (INIS)

Soloviev, V.G.

1980-01-01

Experimental and theoretical data available on few- and many-quasiparticle components of the wave functions of complex nuclei at low, intermediate and high energies are shortly analyzed. The components are treated in the nuclear quasiparticle-phonon model. Specific features of the lowest and high-spin states, giant resonances, neutron resonances and the effects of the energy-level structure in the few-and many-particle transfer reactions are discussed. It is concluded that the most reliable nuclear properties are determined by the components, their behaviour reflecting the shell structure effects. Wich increasing excitation energy the density of levels increases exponentially and the contribution of few-quasiparticle components to the normalization of the wave functions decreases exponentially

Application of Excitation from Multiple Locations on a Simplified High-Lift System

Science.gov (United States)

Melton, LaTunia Pack; Yao, Chung-Sheng; Seifert, Avi

2004-01-01

A series of active flow control experiments were recently conducted on a simplified high-lift system. The purpose of the experiments was to explore the prospects of eliminating all but simply hinged leading and trailing edge flaps, while controlling separation on the supercritical airfoil using multiple periodic excitation slots. Excitation was provided by three. independently controlled, self-contained, piezoelectric actuators. Low frequency excitation was generated through amplitude modulation of the high frequency carrier wave, the actuators' resonant frequencies. It was demonstrated, for the first time, that pulsed modulated signal from two neighboring slots interact favorably to increase lift. Phase sensitivity at the low frequency was measured, even though the excitation was synthesized from the high-frequency carrier wave. The measurements were performed at low Reynolds numbers and included mean and unsteady surface pressures, surface hot-films, wake pressures and particle image velocimetry. A modest (6%) increase in maximum lift (compared to the optimal baseline) was obtained due t o the activation of two of the three actuators.

Asymmetric resonance Raman excitation profiles and violation of the Condon approximation in single-wall carbon nanotubes

Science.gov (United States)

Doorn, Stephen; Duque, Juan; Telg, Hagen; Chen, Hang; Swan, Anna; Haroz, Erik; Kono, Junichiro; Tu, Xiaomin; Zheng, Ming

2012-02-01

DNA wrapping-based ion exchange chromatography and density gradient ultracentrifugation provide nanotube samples highly enriched in single chiralities. We present resonance Raman excitation profiles for the G-band of several single chirality semiconducting and metallic species. The expected incoming and outgoing resonance peaks are observed in the profiles, but contrary to long-held assumptions, the outgoing resonance is always significantly weaker than the ingoing resonance peak. This strong asymmetry in the profiles arises from a violation of the Condon approximation [1]. Results will be discussed in the context of theoretical models that suggest significant coordinate dependence in the transition dipole (non-Condon effects). The generality of the behavior across semiconducting and metallic types, nanotube family, phonon mode, and Eii will be demonstrated. [4pt] [1] J. Duque et. al., ACS Nano, 5, 5233 (2011).

Excitation of the giant quadrupole resonance in /sup 58/Ni with /sup 20/Ne

CERN Document Server

Bohlen, H G; Ingold, G; Lettau, H; Ossenbrink, H; von Oertzen, W

1981-01-01

The heavy-ion induced excitation of the quadrupole resonance in /sup 58/Ni has been studied with /sup 20/Ne beams of 14.5 and 19.6 MeV/N incident energy. The broad resonance structure is clearly observed; the strength exhausts 44% and 60% of the energy weighted sum rule (EWSR) at the two incident energies, respectively. The background is partly explained by a three-body reaction mechanism, which is based on the one-nucleon pick-up reaction into unbound states followed by one- nucleon emission. The remaining part is interpreted as inelastic excitation of other multipoles. (11 refs).

Multi-mode excitation of a clamped–clamped microbeam resonator

KAUST Repository

Younis, Mohammad I.

2015-02-18

We present modeling and simulation of the nonlinear dynamics of a microresonator subjected to two-source electrostatic excitation. The resonator is composed of a clamped–clamped beam excited by a DC voltage load superimposed to two AC voltage loads of different frequencies. One frequency is tuned close to the first natural frequency of the beam and the other is close to the third (second symmetric) natural frequency. A multi-mode Galerkin procedure is applied to extract a reduced-order model, which forms the basis of the numerical simulations. Time history response, Poincare’ sections, Fast Fourier Transforms FFT, and bifurcation diagrams are used to reveal the dynamics of the system. The results indicate complex nonlinear phenomena, which include quasiperiodic motion, torus bifurcations, and modulated chaotic attractors.

Inelastic resonant M-scattering of X-rays from Gd metal with inner-shell excitation

International Nuclear Information System (INIS)

Braicovich, L.; Tagliaferri, A.

1998-01-01

The paper presents results on resonant inner-shell scattering in Gd across the M 5 threshold; the scattering channel with formally a 4 p hole in the final state is studied. Two scattering channels are in competition: one at constant transferred energy and another at constant outgoing energy. The branching ratio of the process at constant transferred energy is about 5%. It's isolated the many-body satellite structure of the formally 4p 3/2 final hole state and it's discussed the importance of the multiplet splitting and of the super Coster-Kronig conversion of this state into another final state with two 4 d holes. The results with resonant M 5 excitation are also compared with those of non-resonant excitation well above the M 4 threshold. Guidelines for future research are briefly presented

Resonant Excitation of Terahertz Surface Plasmons in Subwavelength Metal Holes

Directory of Open Access Journals (Sweden)

Weili Zhang

2007-01-01

Full Text Available We present a review of experimental studies of resonant excitation of terahertz surface plasmons in two-dimensional arrays of subwavelength metal holes. Resonant transmission efficiency higher than unity was recently achieved when normalized to the area occupied by the holes. The effects of hole shape, hole dimensions, dielectric function of metals, polarization dependence, and array film thickness on resonant terahertz transmission in metal arrays were investigated by the state-of-the-art terahertz time-domain spectroscopy. In particular, extraordinary terahertz transmission was demonstrated in arrays of subwavelength holes made even from Pb, a generally poor metal, and having thickness of only one-third of skin depth. Terahertz surface plasmons have potential applications in terahertz imaging, biosensing, interconnects, and development of integrated plasmonic components for terahertz generation and detection.

Selective reflection of resonance radiation from excited media

International Nuclear Information System (INIS)

Veklenko, B.A.; Gusarov, R.B.; Sherkunov, Yu.B.

1998-01-01

According to quantum electrodynamics, the cross section for resonant scattering of radiation on an aggregate of excited atoms can be written as a sum of positive definite terms. This type of structure is not consistent with the Fresnel formulas for the reflection coefficient of radiation from thermally excited media. The difference shows up on a macroscopic level and indicates that semiclassical radiation theory cannot be used. A study of the correlation between elastic scattering and stimulated emission processes clarifies the reason for the discrepancies. The resulting singularities require summing of Feynman diagrams which appear beginning in the sixth order of perturbation theory. A lower bound estimate for the reflection coefficient from a plane layer is given, including processes which violate the statistics of radiation. The contribution of stimulated emission processes caused by the initially scattered photon are examined specifically. An experiment is proposed which would settle the choice of theories

Carbon K-shell excitation in small molecules by high-resolution electron impact

International Nuclear Information System (INIS)

Tronc, M.; King, G.C.; Read, F.H.

1979-01-01

The excitation of 1s carbon electrons has been observed in C0, CH 4 , CF4, C0 2 , COS, C 2 H 2 and C 2 H 4 by means of the electron energy-loss technique with high resolution (70 meV in the 300 eV excitation energy range) and at an incident electron energy of 1.5 keV. The energies, widths and vibrational structures of excited states corresponding to the promotion of 1s carbon electrons to unoccupied valence and Rydberg orbitals have been obtained. The validity of the equivalent-core model, and the role of resonances caused by potential barriers, are discussed. (author)

Characterization of excited electronic states of naphthalene by resonance Raman and hyper-Raman scattering

International Nuclear Information System (INIS)

Bonang, C.C.; Cameron, S.M.

1992-01-01

The first resonance Raman and hyper-Raman scattering from naphthalene are reported. Fourth harmonic of a mode-locked Nd:YAG laser is used to resonantly excite the 1 B 1u + transition, producing Raman spectra that confirm the dominance of the vibronically active ν 28 (b 3g ) mode and the Franck--Condon active a g modes, ν 5 and ν 3 . A synchronously pumped stilbene dye laser and its second harmonic are employed as the excitation sources for hyper-Raman and Raman scattering from the overlapping 1 B 2 u + and 1 A g - states. The Raman spectra indicate that the equilibrium geometry of naphthalene is distorted primarily along ν 5 , ν 8 , and ν 7 normal coordinates upon excitation to 1 B 2 u + . The hyper-Raman spectrum shows that ν 25 (b 2u ) is the mode principally responsible for vibronic coupling between the 1 A g - and 1 B 2u + states. The results demonstrate the advantageous features of resonance hyper-Raman scattering for the case of overlapping one- and two-photon allowed transitions. Calculations based on simple molecular orbital configurations are shown to qualitatively agree with the experimental results

Electron-impact excitation of the In+ ion resonance line

International Nuclear Information System (INIS)

Gomonai, A.; OvcharenkO, E.; Imre, A.; Hutych, Yu.

2004-01-01

Full text: Study of the electron-impact excitation of the In + ion is important not only for atomic structure research, but also for applications to astrophysics, analytical techniques and fusion research, as well as for new applications of this ion such as a component of solid state laser media and as a source for an optical frequency standart. The energy dependence of the electron-impact excitation of the In + ion resonance line was studied by spectroscopic method using the crossed-beam technique in the energy range from the threshold up to 300 eV for the following process: e + In + (4d 10 5s 2 ) 1 S 0 e' + In + (4d 10 5s5p) 1 P 0 1 e' + In + (4d 10 5s 2 ) 1 S 0 +h (1) Process (1) includes the direct electron-impact excitation of the 5s5p 1 P 0 1 state from the ground 5s 2 1 S 0 state, as well as the contribution of the cascade transitions and resonance processes: In + (4d 10 5s nln 1 l 1 , 4d 10 5p 2 nl, 4d 9 5s 2 nln 1 l 1 ) In + (4d 10 5s 2 ) 1 S 0 + e' (2) The peculiarity of this investigation is the presence of low lying metastable states and high temperature (T1250K) of atomic vapour. The ions produced in the ion source on the heated tantalum surface were extracted, focused and accelerated by a system of ion optical lenses into a beam (E i = 700eV, I i (11.4)10 -6 A), separated from neutral atoms by means of a 90 deg electrostatic selector and crossed at the right angle by the ribbon electron beam (E e = (7300)eV, Ie = (610)10 -5 A, 0 1/2 (0.40.5)eV) in the collision region (at P 10 -8 Torr) [1]. Radiation observed at 90 deg with respect to the beam intersection plane was spectrally separated by a 70 deg vacuum monochromator (d/dl = 1.7nm/mm) based on the Seya- Namioka scheme and detected by a photomultiplier. The measurements and experimental data processing were realised by means of a PC. The drop of the energy dependence of the excitation cross section obey the E -1 lnE rule specific for the optically allow transitions. A distinct structure in the energy

Resonant spin wave excitations in a magnonic crystal cavity

Science.gov (United States)

Kumar, N.; Prabhakar, A.

2018-03-01

Spin polarized electric current, injected into permalloy (Py) through a nano contact, exerts a torque on the magnetization. The spin waves (SWs) thus excited propagate radially outward. We propose an antidot magnonic crystal (MC) with a three-hole defect (L3) around the nano contact, designed so that the frequency of the excited SWs, lies in the band gap of the MC. L3 thus acts as a resonant SW cavity. The energy in this magnonic crystal cavity can be tapped by an adjacent MC waveguide (MCW). An analysis of the simulated micromagnetic power spectrum, at the output port of the MCW reveals stable SW oscillations. The quality factor of the device, calculated using the decay method, was estimated as Q > 105 for an injected spin current density of 7 ×1012 A/m2.

Efficient H2 production over Au/graphene/TiO2 induced by surface plasmon resonance of Au and band-gap excitation of TiO2

International Nuclear Information System (INIS)

Liu, Yang; Yu, Hongtao; Wang, Hua; Chen, Shuo; Quan, Xie

2014-01-01

Highlights: • Both surface plasmon resonance and band-gap excitation were used for H 2 production. • Au/Gr/TiO 2 composite photocatalyst was synthesized. • Au/Gr/TiO 2 exhibited enhancement of light absorption and charge separation. • H 2 production rate of Au/Gr/TiO 2 was about 2 times as high as that of Au/TiO 2 . - Abstract: H 2 production over Au/Gr/TiO 2 composite photocatalyst induced by surface plasmon resonance of Au and band-gap excitation of TiO 2 using graphene (Gr) as an electron acceptor has been investigated. Electron paramagnetic resonance study indicated that, in this composite, Gr collected electrons not only from Au with surface plasmon resonance but also from TiO 2 with band-gap excitation. Surface photovoltage and UV–vis absorption measurements revealed that compared with Au/TiO 2 , Au/Gr/TiO 2 displayed more effective photogenerated charge separation and higher optical absorption. Benefiting from these advantages, the H 2 production rate of Au/Gr/TiO 2 composite with Gr content of 1.0 wt% and Au content of 2.0 wt% was about 2 times as high as that of Au/TiO 2 . This work represents an important step toward the efficient application of both surface plasmon resonance and band-gap excitation on the way to converting solar light into chemical energy

Doubly excited 3Pe resonance states of two-electron positive ions in Debye plasmas

International Nuclear Information System (INIS)

Hu, Xiao-Qing; Wang, Yang; Kar, Sabyasachi; Jiang, Zishi; Jiang, Pinghui

2015-01-01

We investigate the doubly excited 3 P e resonance states of two-electron positive ions Li + , Be 2+ , B 3+ , and C 4+ by employing correlated exponential wave functions. In the framework of the stabilization method, we calculate two series (3pnp and 3dnd) of 3 P e resonances below the N = 3 threshold. The 3 P e resonance parameters (resonance energies and widths) are reported for the first time as a function of the screening parameter. For free-atomic cases, comparisons are made with the reported results and few resonance states are reported for the first time

Elementary excitations in nuclei

International Nuclear Information System (INIS)

Lemmer, R.H.

1987-01-01

The role of elementary quasi-particle and quasi-hole excitations is reviewed in connection with the analysis of data involving high-lying nuclear states. This article includes discussions on: (i) single quasi-hole excitations in pick-up reactions, (ii) the formation of single quasi-hole and quasi-particle excitations (in different nuclei) during transfer reactions, followed by (iii) quasi-particle quasi-hole excitations in the same nucleus that are produced by photon absorption. Finally, the question of photon absorption in the vicinity of the elementary Δ resonance is discussed, where nucleonic as well as nuclear degrees of freedom can be excited

Theory and computation of triply excited resonances: Application to states of He-

International Nuclear Information System (INIS)

Nicolaides, C.A.; Piangos, N.A.; Komninos, Y.

1993-01-01

Autoionizing multiply excited states offer unusual challenges to the theory of electronic structure and spectra because of the presence of strong electron correlations, of their occasional weak binding, of their proximity to more than one threshold, and of their degeneracy with many continua. Here we discuss a theory that addresses these difficulties in conjunction with the computation of their wave functions and intrinsic properties. Emphasis is given on the justification of the possible presence of self-consistently obtained open-channel-like (OCL) correlating configurations in the square-integrable representation of such states and on their effect on the energy E and the width Γ. Application of the theory has allowed the prediction of two hitherto unknown He - triply excited resonances, the 2s2p 2 2 P (E=59.71 eV, above the He ground state, Γ=79 meV) and the 2p 3 2 Do (E=59.46 eV, Γ=282 meV) (1 a.u.=27.2116 eV). These resonances are above the singly excited states of He and are embedded in its doubly excited spectrum. The relatively broad 2p 3 2 Do state interacts strongly with the He 2s2p 3 Po εd continuum. The effect of this interaction has been studied in terms of the coupling with fixed core scattering states as well as with a self-consistently computed OCL bound configuration

Rotational distributions of molecular photoions following resonant excitation

International Nuclear Information System (INIS)

Poliakoff, E.D.; Chan, J.C.K.; White, M.G.

1986-01-01

We demonstrate that the photoelectron energy mediates the rotational energy distribution of N + 2 ions created by photoionization, and conversely, that rotational energy determinations probe resonant excitation in molecular photoionization. Experimentally, this is accomplished by monitoring the dispersed fluorescence from N + 2 (B 2 Σ + /sub u/) photoions to determine their rotational energy distribution. These results demonstrate that while dipole selection rules constrain the total angular momentum of the electron--ion complex, the partitioning of angular momentum between the photoelectron and photoion depends on the photoejection dynamics. Implications for photoionization and electron impact ionizatin studies are discussed

Development of Selective Excitation Methods in Nuclear Magnetic Resonance: Investigation of Hemoglobin Oxygenation in Erythrocytes Using Proton and Phosphorus -31 Nuclear Magnetic Resonance

Science.gov (United States)

Fetler, Bayard Keith

1993-01-01

Nuclear magnetic resonance (NMR) offers a potential method for making measurements of the percent oxygenation of hemoglobin (Hb) in living tissue non-invasively. As a demonstration of the feasibility of such measurements, we measured the percent oxygenation of Hb in red blood cells (erythrocytes) using resonances in the proton-NMR (^1H-NMR) spectrum which are characteristic of oxyhemoglobin (oxy-Hb) and deoxyhemoglobin (deoxy-Hb), and are due to the unique magnetic properties of these molecules. To perform these measurements, we developed a new NMR method of selectively exciting signals in a region of interest with uniform phase and amplitude, while suppressing the signal of the water resonance. With this method, we are able to make exact calculations distinguishing between uniform phase excitation produced at large flip-angles using the non-linear properties of the Bloch equations, and uniform phase excitation produced at small flip-angles using asymmetric pulse excitation functions. We measured the percent oxygenation of three characteristic ^1H-NMR resonances of Hb: two from deoxy-Hb, originating from the N_delta H protons of histidine residue F8, which occur at different frequencies for the alpha and beta chains of Hb; and one from oxy-Hb, originating from the gamma_2 -CH_3 protons of valine residue E11. We performed experiments both on fresh erythrocytes and on erythrocytes depleted of 2,3-diphosphoglycerate (2,3-DPG), and found that oxygen is more tightly bound to Hb in the former case. In both fresh and 2,3-DPG-depleted samples, we found that: (i) from the deoxy-Hb marker resonances, there is a small but significant difference in the oxygen saturation between the alpha and beta chains; (ii) the decrease in the areas of the deoxy-Hb marker resonances correlates well with the increase in the percent oxygenation of Hb as measured optically; (iii) the area of the oxy-Hb marker resonance may be up to ~15% less than the optically measured Hb saturation. We are

Role of nucleon resonance excitation in φ meson photoproduction

International Nuclear Information System (INIS)

Zhao, Q.; Didelez, J.P.; Guidal, M.; Saghai, B.

2000-01-01

The resonance effects are investigated in the φ meson photoproduction near threshold through a quark model approach with an effective Lagrangian. The diffractive contribution is consistently estimated by the t-channel Pomeron exchange. Another non-diffractive process, t-channel π 0 exchange is also included. The numerical result shows that the Pomeron exchange plays dominant role in the φ meson photoproduction, while the cross sections of the non-diffractive processes, i.e., s- and u-channel excitations, and t-channel π 0 exchange, are quite small. In the polarization observables, we find that large asymmetries are produced in the backward direction by the interferences from the s- and u-channel resonances, while in the forward direction, only very small asymmetries are generated. Meanwhile, we find that the effects from the π 0 exchange are generally negligible. (author)

Multi-frequency excitation

KAUST Repository

Younis, Mohammad I.

2016-03-10

Embodiments of multi-frequency excitation are described. In various embodiments, a natural frequency of a device may be determined. In turn, a first voltage amplitude and first fixed frequency of a first source of excitation can be selected for the device based on the natural frequency. Additionally, a second voltage amplitude of a second source of excitation can be selected for the device, and the first and second sources of excitation can be applied to the device. After applying the first and second sources of excitation, a frequency of the second source of excitation can be swept. Using the methods of multi- frequency excitation described herein, new operating frequencies, operating frequency ranges, resonance frequencies, resonance frequency ranges, and/or resonance responses can be achieved for devices and systems.

Quantum resonances in a single plaquette of Josephson junctions: excitations of Rabi oscillations

Science.gov (United States)

Fistul, M. V.

2002-03-01

We present a theoretical study of a quantum regime of the resistive (whirling) state of dc driven anisotropic single plaquette containing small Josephson junctions. The current-voltage characteristics of such systems display resonant steps that are due to the resonant interaction between the time dependent Josephson current and the excited electromagnetic oscillations (EOs). The voltage positions of the resonances are determined by the quantum interband transitions of EOs. We show that in the quantum regime as the system is driven on the resonance, coherent Rabi oscillations between the quantum levels of EOs occur. At variance with the classical regime the magnitude and the width of resonances are determined by the frequency of Rabi oscillations that in turn, depends in a peculiar manner on an externally applied magnetic field and the parameters of the system.

Resonant excitation and the decay of autoionization states in a strong electromagnetic field

International Nuclear Information System (INIS)

Andryushin, A.I.; Kazakov, A.E.; Fedorov, M.V.

1985-01-01

Photoionization of atoms involving resonant excitation of the auto-ionization state is studied. The evolution of the total ionization probability, its dependence on the frequency of the resonance radiation and also the photoelectron energy spectrum are investigated. It is shown that the energy of the final state of the system may be localized either in the vicinity of E approximately Esub(α), where Esub(α) is the auto-ionization energy, or in the vicinity of E approximately Esub(α)+h/2πω where h/2πω is the quantum energy of the resonance radiation. The photoelectron specturum in the region E approximately Esub(α)+h/2πω as a whole is similar to the electron spectrum on photoionization of atoms involving resonance excitation of the bound state. A strong effect on the photoelectron spectrum in the region E approximately Esub(α) is exerted by interference of various decay channels of the ground state in the resonance field which leads to the appearance in the spectrum of a characteristic structure of the Fano type. Interence also affects the widths of the two spectral curves, the relatve amount of electrons in the two energy ranges and also other characteristics of the ionization process. It is shown that the presence of a noninterfering photoionization channel of the autoionization state ensures the finiteness of the swidths and heights of the spectral curves and the absence of complete ''coherency merging''

High resolution detection and excitation of resonant magnetic perturbations in a wall-stabilized tokamak

Energy Technology Data Exchange (ETDEWEB)

Maurer, David A. [Physics Department, Auburn University, Auburn, Alabama 36849 (United States); Shiraki, Daisuke; Levesque, Jeffrey P.; Bialek, James; Angelini, Sarah; Byrne, Patrick; DeBono, Bryan; Hughes, Paul; Mauel, Michael E.; Navratil, Gerald A.; Peng Qian; Rhodes, Dov; Rath, Nickolaus; Stoafer, Christopher [Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027 (United States)

2012-05-15

We report high-resolution detection of the 3D plasma magnetic response of wall-stabilized tokamak discharges in the High Beta Tokamak-Extended Pulse [T. H. Ivers et al., Phys. Plasmas 3, 1926 (1996)] device. A new adjustable conducting wall has been installed on HBT-EP made up of 20 independent, movable, wall segments instrumented with three distinct sets of 40 modular coils that can be independently driven to generate a wide variety of magnetic perturbations. High-resolution detection of the plasma response is made with 216 poloidal and radial magnetic sensors that have been located and calibrated with high-accuracy. Static and dynamic plasma responses to resonant and non-resonant magnetic perturbations are observed through measurement of the step-response following a rapid change in the toroidal phase of the applied perturbations. Biorthogonal decomposition of the full set of magnetic sensors clearly defines the structures of naturally occurring external kinks as being composed of independent m/n = 3/1 and 6/2 modes. Resonant magnetic perturbations were applied to discharges with pre-existing, saturated m/n = 3/1 external kink mode activity. This m/n = 3/1 kink mode was observed to lock to the applied perturbation field. During this kink mode locked period, the plasma resonant response is characterized by a linear, a saturated, and a disruptive plasma regime dependent on the magnitude of the applied field and value of the edge safety factor and plasma rotation.

Resonant excitation of coupled Rayleigh waves in a short and narrow fluid channel clad between two identical metal plates

Directory of Open Access Journals (Sweden)

Victor M. García-Chocano

2011-12-01

Full Text Available Transmission of ultrasonic waves through a slit between two water immersed brass plates is studied for sub-wavelength plate thicknesses and slit apertures. Extraordinary high absorption is observed at discrete frequencies corresponding to resonant excitation of Rayleigh waves on the both sides of the channel. The coupling of the Rayleigh waves occurs through the fluid and the corresponding contribution to the dispersion has been theoretically derived and also experimentally confirmed. Symmetric and anti-symmetric modes are predicted but only the symmetric mode resonances have been observed. It follows from the dispersion equation that the coupled Rayleigh waves cannot be excited in a channel with apertures less than the critical one. The calculated critical aperture is in a good agreement with the measured acoustic spectra. These findings could be applied to design a broadband absorptive metamaterial.

Quanty for core level spectroscopy - excitons, resonances and band excitations in time and frequency domain

International Nuclear Information System (INIS)

Haverkort, Maurits W.

2016-01-01

Depending on the material and edge under consideration, core level spectra manifest themselves as local excitons with multiplets, edge singularities, resonances, or the local projected density of states. Both extremes, i.e., local excitons and non-interacting delocalized excitations are theoretically well under control. Describing the intermediate regime, where local many body interactions and band-formation are equally important is a challenge. Here we discuss how Quanty , a versatile quantum many body script language, can be used to calculate a variety of different core level spectroscopy types on solids and molecules, both in the frequency as well as the time domain. The flexible nature of Quanty allows one to choose different approximations for different edges and materials. For example, using a newly developed method merging ideas from density renormalization group and quantum chemistry [1-3], Quanty can calculate excitons, resonances and band-excitations in x-ray absorption, photoemission, x-ray emission, fluorescence yield, non-resonant inelastic x-ray scattering, resonant inelastic x-ray scattering and many more spectroscopy types. Quanty can be obtained from: http://www.quanty.org. (paper)

Excited baryon form factors at high Q2

International Nuclear Information System (INIS)

Paul Stoler; Gary Adams; Abdellah Ahmidouch; Chris Armstrong; K. Assamagan; Steven Avery; K. Baker; Peter Bosted; Volker Burkert; Jim Dunne; Tom Eden; Rolf Ent; V. Frolov; David Gaskell; P. Gueye; Wendy Hinton; Cynthia Keppel; Wooyoung Kim; Michael Klusman; Doug Koltenuk; David Mack; Richard Madey; David Meekins; Ralph Minehart; Joseph Mitchell; Hamlet Mkrtchyan; James Napolitano; Gabriel Niculescu; Ioana Niculescu; Mina Nozar; John Price; Paul Stoler; Vardan Tadevosyan; Liguang Tang; Michael Witkowski; Stephen Wood

1998-01-01

The role of resonance electroproduction at high Q 2 is discussed in the context of exclusive reactions, as well as the alternative theoretical models which are proposed to treat exclusive reactions in the few GeV 2 /c 2 region of momentum transfer. Jefferson Lab experiment 94-014, which measured the excitation of the Delta (1232) and S 11 (1535) via the reactions p(e,e ' p)pi 0 and p(e,e ' p)eta respectively at Q 2 ∼ 2.8 and 4 GeV 2 /c 2 is described, and the state of analysis reported

Parity dependence of the nuclear level density at high excitation

International Nuclear Information System (INIS)

Rao, B.V.; Agrawal, H.M.

1995-01-01

The basic underlying assumption ρ(l+1, J)=ρ(l, J) in the level density function ρ(U, J, π) has been checked on the basis of high quality data available on individual resonance parameters (E 0 , Γ n , J π ) for s- and p-wave neutrons in contrast to the earlier analysis where information about p-wave resonance parameters was meagre. The missing level estimator based on the partial integration over a Porter-Thomas distribution of neutron reduced widths and the Dyson-Mehta Δ 3 statistic for the level spacing have been used to ascertain that the s- and p-wave resonance level spacings D(0) and D(1) are not in error because of spurious and missing levels. The present work does not validate the tacit assumption ρ(l+1, J)=ρ(l, J) and confirms that the level density depends upon parity at high excitation. The possible implications of the parity dependence of the level density on the results of statistical model calculations of nuclear reaction cross sections as well as on pre-compound emission have been emphasized. (orig.)

Technology of discharge and laser resonators for high power CO2 lasers. Koshutsuryoku CO2 laser ni tsukawareru hoden reiki laser kyoshinki gijutsu

Energy Technology Data Exchange (ETDEWEB)

Takenaka, Y.; Kuzumoto, M. (Mitsubishi Electric Corp., Tokyo (Japan))

1994-03-20

This paper describes discharge excitation technology and resonator technology as basic technologies for high power CO2 lasers. As a result of progress in high-frequency power element techniques, the discharge excitation technology now generally uses laser excitation using AC discharge of capacity coupling type. Its representative example is silent discharge (SD) excitation. This is a system to excite laser by applying high voltages with as high frequency as 100 kHz to 1 MHz across a pair of electrodes covered with a dielectric material. The system maintains stability in discharge even if power supply voltage amplitude is modulated, and easily provides pulse outputs. Discharge excitation for diffusion cooled type CO2 laser generates a discharge in a gap with a gap length of about 2 mm, and can perform gas cooling by means of thermal conduction of gas, whereas a compact resonator can be fabricated. A resonator for the diffusion cooled type CO2 laser eliminates gas circulation and cooling systems, hence the device can be made more compact. A report has been given that several of these compact resonators were combined, from which a laser output of 85W was obtained by using RF discharge of 2kW. 43 refs., 21 figs.

Multi frequency excited MEMS cantilever beam resonator for Mixer-Filter applications

KAUST Repository

Chandran, Akhil A.

2016-09-15

Wireless communication uses Radio Frequency waves to transfer information from one point to another. The modern RF front end devices are implementing MEMS in their designs so as to exploit the inherent properties of MEMS devices, such as its low mass, low power consumption, and small size. Among the components in the RF transceivers, band pass filters and mixers play a vital role in achieving the optimum RF performance. And this paper aims at utilizing an electrostatically actuated micro cantilever beam resonator\\'s nonlinear frequency mixing property to realize a Mixer-Filter configuration through multi-frequency excitation. The paper studies about the statics and dynamics of the device. Simulations are carried out to study the added benefits of multi frequency excitation. The modelling of the cantilever beam has been done using a Reduced Order Model of the Euler-Bernoulli\\'s beam equation by implementing the Galerkin discretization. The device is shown to be able to down-convert signals from 960 MHz of frequency to an intermediate frequency around 50 MHz and 70 MHz in Phase 1 and 2, respectively. The simulation showed promising results to take the project to the next level. © 2016 IEEE.

Decay of the giant quadrupoles resonance and higher excitation states in 40Ca

International Nuclear Information System (INIS)

Alamanos, N.; Fernandez, B.; Gillibert, A.

1991-01-01

Light charged particles have been measured in coincidence with inelastically scattered fragments from the 40 Ca + 40 Ca reaction at 50 MeV/N. Such a measurement allows to unravel the different reaction mechanisms contributing to the inelastic spectrum: pick-up break-up reactions, knock out and inelastic excitations. The giant quadrupole resonance in 40 Ca is shown to present a 30% non statistical decay branch. A prominent structure at 34 MeV is attributed to target excitation, the decay of this structure is studied

Electron dynamics in the core-excited CS2 molecule revealed through resonant inelastic x-ray scattering spectroscopy

International Nuclear Information System (INIS)

Marchenko, T; Carniato, S; Journel, L; Guillemin, R; Kawerk, E; Simon, M; Žitnik, M; Kavčič, M; Bučar, K; Bohinc, R; Petric, M; Da Cruz, V Vaz; Gel'mukhanov, F

2015-01-01

We present an experimental and theoretical study of resonant inelastic x-ray scattering (RIXS) in the CS 2 molecule near the S 1s edge. We show that localization of the S 1s core-hole occurs in CS 2 during the RIXS process due to the orientational dephasing of interference between the waves scattering on the two sulfur atoms. Strong evolution of the RIXS profile with the excitation energy far below the first absorption resonance reflects the onset of electron dynamics triggered by a coherent excitation of multiple electronic states. (paper)

Resonance Raman spectra of organic molecules absorbed on inorganic semiconducting surfaces: Contribution from both localized intramolecular excitation and intermolecular charge transfer excitation

International Nuclear Information System (INIS)

Ye, ChuanXiang; Zhao, Yi; Liang, WanZhen

2015-01-01

The time-dependent correlation function approach for the calculations of absorption and resonance Raman spectra (RRS) of organic molecules absorbed on semiconductor surfaces [Y. Zhao and W. Z. Liang, J. Chem. Phys. 135, 044108 (2011)] is extended to include the contribution of the intermolecular charge transfer (CT) excitation from the absorbers to the semiconducting nanoparticles. The results demonstrate that the bidirectionally interfacial CT significantly modifies the spectral line shapes. Although the intermolecular CT excitation makes the absorption spectra red shift slightly, it essentially changes the relative intensities of mode-specific RRS and causes the oscillation behavior of surface enhanced Raman spectra with respect to interfacial electronic couplings. Furthermore, the constructive and destructive interferences of RRS from the localized molecular excitation and CT excitation are observed with respect to the electronic coupling and the bottom position of conductor band. The interferences are determined by both excitation pathways and bidirectionally interfacial CT

Sensitivity of nonlinear photoionization to resonance substructure in collective excitation

Science.gov (United States)

Mazza, T.; Karamatskou, A.; Ilchen, M.; Bakhtiarzadeh, S.; Rafipoor, A. J.; O'Keeffe, P.; Kelly, T. J.; Walsh, N.; Costello, J. T.; Meyer, M.; Santra, R.

2015-01-01

Collective behaviour is a characteristic feature in many-body systems, important for developments in fields such as magnetism, superconductivity, photonics and electronics. Recently, there has been increasing interest in the optically nonlinear response of collective excitations. Here we demonstrate how the nonlinear interaction of a many-body system with intense XUV radiation can be used as an effective probe for characterizing otherwise unresolved features of its collective response. Resonant photoionization of atomic xenon was chosen as a case study. The excellent agreement between experiment and theory strongly supports the prediction that two distinct poles underlie the giant dipole resonance. Our results pave the way towards a deeper understanding of collective behaviour in atoms, molecules and solid-state systems using nonlinear spectroscopic techniques enabled by modern short-wavelength light sources. PMID:25854939

High-Q, in-plane modes of nanomechanical resonators operated in air

Science.gov (United States)

Waggoner, Philip S.; Tan, Christine P.; Bellan, Leon; Craighead, Harold G.

2009-05-01

Nanomechanical resonators have traditionally been limited to use in vacuum due to low quality factors that come as a result of viscous damping effects in air or liquid. We have fabricated arrays of 90 nm thick trampoline-shaped resonators, studied their resonant frequency spectrum as a function of pressure, and found that some high frequency modes exhibit quality factors over 2000 at atmospheric pressure. We have excited the in-plane resonances of these devices, verified their identities both experimentally and with finite element modeling, and demonstrated their advantageous characteristics for ambient sensing. Even after deposition of a relatively thick polymer layer, the in-plane resonant modes still boast quality factors on the order of 2000. These results show promise for the use of nanomechanical resonant sensors in real-time atmospheric sensing applications.

RESONANT PROCESSES IN STARTING MODES OF SYNCHRONOUS MOTORS WITH CAPACITORS IN THE EXCITATION WINDINGS CIRCUIT

Directory of Open Access Journals (Sweden)

V. S. Malyar

2017-08-01

Full Text Available Purpose. Development of a mathematical model that enables to detect resonance modes during asynchronous startup of salient-pole synchronous motors, in which capacitors are switched on to increase the electromagnetic moment in the circuit of the excitation winding. Methodology. The asynchronous mode is described by a system of differential equations of the electric equilibrium of motor circuits written in orthogonal coordinate axes. The basis of the developed algorithm is the mathematical model of the high-level adequacy motor and the projection method for solving the boundary value problem for the equations of the electric equilibrium of the circuits written in orthogonal coordinate axes, taking into account the presence of capacitors in the excitation winding. The coefficients of differential equations are the differential inductances of the motor circuits, which are determined on the basis of the calculation of its magnetic circuit. As a result of the asymmetry of the rotor windings in the asynchronous mode, the current coupling and currents change according to the periodic law. The problem of its definition is solved as a boundary one. Results. A mathematical model for studying the asynchronous characteristics of synchronous motors with capacitors in an excitation winding is developed, by means of which it is possible to investigate the influence of the size of the capacity on the motor's starting properties and the resonance processes which may arise in this case. Scientific novelty. The developed method of mathematical modeling is based on a fundamentally new mathematical basis for the calculation of stationary dynamic modes of nonlinear electromagnetic circuits, which enables to obtain periodic coordinate dependencies, without resorting to the calculation of the transients. The basis of the developed algorithm is based on the approximation of state variables by cubic splines, the projection method of decomposition for the boundary value

Electron Dynamics in the Core-Excited CS_{2} Molecule Revealed through Resonant Inelastic X-Ray Scattering Spectroscopy

Directory of Open Access Journals (Sweden)

T. Marchenko

2015-08-01

Full Text Available We present an experimental and theoretical study of resonant inelastic x-ray scattering (RIXS in the carbon disulphide CS_{2} molecule near the sulfur K-absorption edge. We observe a strong evolution of the RIXS spectral profile with the excitation energy tuned below the lowest unoccupied molecular orbital (LUMO absorption resonance. The reason for this is twofold. Reducing the photon energy in the vicinity of the LUMO absorption resonance leads to a relative suppression of the LUMO contribution with respect to the emission signal from the higher unoccupied molecular orbitals, which results in the modulation of the total RIXS profile. At even larger negative photon-energy detuning from the resonance, the excitation-energy dependence of the RIXS profile is dominated by the onset of electron dynamics triggered by a coherent excitation of multiple electronic states. Furthermore, our study demonstrates that in the hard x-ray regime, localization of the S 1s core hole occurs in CS_{2} during the RIXS process because of the orientational dephasing of interference between the waves scattering on the two sulfur atoms. Core-hole localization leads to violation of the symmetry selection rules for the electron transitions observed in the spectra.

Systematics of the excitation of M1 resonances in medium heavy nuclei by 200 MeV proton inelastic scattering

International Nuclear Information System (INIS)

Djalali, C.; Marty, N.; Morlet, M.

1982-01-01

In a series of seventeen nuclei ranging from 51 V to 140 Ca, broad resonance structures are observed at energies between 8 and 10 MeV, nearly mass independent. These resonances have very forward peaked angular distributions which imply that they are populated by an angular momentum transfer of zero. This together with the observed excitation energies suggests an M1 character for these resonances. In 51 V, 58 Ni, 60 Ni, 62 Ni, a sharp peak located at an excitation energy above the threshold for neutron emission is interpreted as a part of the T 0+1 component of the M1 resonances. Cross-sections are given for all the M1 resonances. For 58 Ni, 90 Zr, 92 Mo, 120 Sn and 140 Ca, an ''attenuation'' factor for the cross-sections is extracted in a OWIA calculation assuming simple shell model structures for these resonances

Distribution of radiative strength with excitation energy: the E1 and M1 giant resonances

International Nuclear Information System (INIS)

Brown, G.E.; Speth, J.

1979-01-01

Calculations of the giant dipole resonance in the particle-hole model, employing empirical values for the unperturbed particle and hole energies, have been unsuccessful in pushing the dipole state to a sufficiently high energy. it is argued that unperturbed levels correspondign to an effective mass of m*/m approx. 0.6 to 0.7 should be employed. The couplings of particles and holes to vibrations are the crucial ingredients in these considerations. More generally, it is argued that the effective mass relevant to excitations near the Fermi surface is that corresponding to empirical single-particle levels, m*/m greater than or equal to 1.0. For particle-hole excitations above the Fermi surface, it is a decreasing function of excitation energy, reaching the above values 0.6 to 0.7 for E greater than or equal to 2 dirac constant/b omega, dirac constant/sub omega/ being the shell spacing. This has the consequence of spreading out the M1 strength. A new interpretation of experimental strengths is proposed

Resonance Polarization and Phase-Mismatched CARS of Pheophytin b Excited in the Qy Band

NARCIS (Netherlands)

de Boeij, W.P.; Lucassen, G.W.; Lucassen, Gerald; Otto, Cornelis; Greve, Jan

1993-01-01

Resonance polarization and phase-mismatched coherent anti-Stokes Raman scattering (CARS) measurements were performed on pheophytin b dissolved in acetone excited in the Qy absorption band, where strong broad fluorescence makes spontaneous Raman spectroscopy impossible. The phase-mismatching

Excitation of helium resonance lines in solar flares

International Nuclear Information System (INIS)

Porter, J.G.; Gebbie, K.B.; November, L.J.; Joint Institute for Laboratory Astrophysics, Boulder, CO; National Solar Observatory, Sunspot, NM)

1985-01-01

Helium resonance line intensities are calculated for a set of six flare models corresponding to two rates of heating and three widely varying incident fluxes of soft X-rays. The differing ionization and excitation equilibria produced by these models, the processes which dominate the various cases, and the predicted helium line spectra are examined. The line intensities and their ratios are compared with values derived from Skylab NRL spectroheliograms for a class M flare, thus determining which of these models most nearly represents the density vs temperature structure and soft X-ray flux in the flaring solar transition region, and the temperature and dominant mechanaism of formation of the helium line spectrum during a flare. 26 references

Nonlinear Resonance Analysis of Slender Portal Frames under Base Excitation

Directory of Open Access Journals (Sweden)

Luis Fernando Paullo Muñoz

2017-01-01

Full Text Available The dynamic nonlinear response and stability of slender structures in the main resonance regions are a topic of importance in structural analysis. In complex problems, the determination of the response in the frequency domain indirectly obtained through analyses in time domain can lead to huge computational effort in large systems. In nonlinear cases, the response in the frequency domain becomes even more cumbersome because of the possibility of multiple solutions for certain forcing frequencies. Those solutions can be stable and unstable, in particular saddle-node bifurcation at the turning points along the resonance curves. In this work, an incremental technique for direct calculation of the nonlinear response in frequency domain of plane frames subjected to base excitation is proposed. The transformation of equations of motion to the frequency domain is made through the harmonic balance method in conjunction with the Galerkin method. The resulting system of nonlinear equations in terms of the modal amplitudes and forcing frequency is solved by the Newton-Raphson method together with an arc-length procedure to obtain the nonlinear resonance curves. Suitable examples are presented, and the influence of the frame geometric parameters and base motion on the nonlinear resonance curves is investigated.

M series resonant x-ray lines of barium for near threshold electron excitation

International Nuclear Information System (INIS)

Morgon, D.V.

1992-01-01

An investigation of the M series resonant x-ray emission lines of barium for near threshold electron excitation was undertaken with a vacuum double crystal spectrometer equipped with potassium acid phthalate crystals. X-ray continuum isochromats were obtained for barium samples using the double crystal spectrometer as a monochrometer set to pass 532 eV photons. The rotatable anode allowed the samples to be observed by either the double crystal spectrometer or a soft x-ray appearance potential spectrometer, which was used for monitoring the surface of the varium sample for contamination, and to provide a cross-check for the double crystal spectrometer data. Barium M series characteristic x-ray spectra for 2.0 keV electron excitation were obtained for a variety of samples, and it was discovered that the fluorescent and resonant x-ray emission line energies remained virtually the same, regardless of the chemical condition of the sample. The continuum resonance effect was observed for near-threshold energy electron excitation, but it was significantly weaker than the same effect observed previously for lanthanum or cerium. The electron excitation energy and intensity of this effect were strongly dependent on the chemical condition of the barium sample. X-ray continuum isochromats were observed for pure and contaminated barium samples at a photon energy of 532 eV. For pure metallic barium, a peak associated with 4f electronic states was observed at an energy of about 10.2 eV above the Fermi level. When the sample was exposed to 1.5 x 10 4 Langmuir of air, the 4f structure became more sharply peaked, and shifted to an energy of about 12.0 eV above the Fermi level. A continuum isochromat of barium oxide was also observed. Chemical shifts in barium M IV and M V appearance potential spectra are therefore caused soley by shifts in the energy position of the empty 4f electronic states relative to the Fermi level

Shifted excitation resonance Raman difference spectroscopy using a microsystem light source at 488 nm

Science.gov (United States)

Maiwald, M.; Sowoidnich, K.; Schmidt, H.; Sumpf, B.; Erbert, G.; Kronfeldt, H.-D.

2010-04-01

Experimental results in shifted excitation resonance Raman difference spectroscopy (SERRDS) at 488 nm will be presented. A novel compact diode laser system was used as excitation light source. The device is based on a distributed feedback (DFB) diode laser as a pump light source and a nonlinear frequency doubling using a periodically poled lithium niobate (PPLN) waveguide crystal. All elements including micro-optics are fixed on a micro-optical bench with a footprint of 25 mm × 5 mm. An easy temperature management of the DFB laser and the crystal was used for wavelength tuning. The second harmonic generation (SHG) provides an additional suppression of the spontaneous emission. Raman spectra of polystyrene demonstrate that no laser bandpass filter is needed for the Raman experiments. Resonance-Raman spectra of the restricted food colorant Tartrazine (FD&C Yellow 5, E 102) in distilled water excited at 488 nm demonstrate the suitability of this light source for SERRDS. A limit of detection (LOD) of 0.4 μmol.l-1 of E102 enables SERRDS at 488 nm for trace detection in e.g. food safety control as an appropriate contactless spectroscopic technique.

Nonordinary excitation of hydroacoustic resonance in the hydroturbine circuit of the sayano-shushenskaya hydroelectric power plant

Science.gov (United States)

Karavosov, R. K.; Prozorov, A. G.

2011-05-01

Three cases of excitation of resonance oscillations in a circuit with an incompressible medium and a hydrodynamic source of narrow-band acoustic radiation are compared. It is asserted that the Francis turbine can transmit and reflect infrasonic disturbances. It is supposed that an array of immobile coaxial cylinders below the impeller will prevent hydroacoustic self-excitation in flow inside the water conduit.

Thermal and rotational effect on giant dipole resonances in rotating nuclei at high temperature

International Nuclear Information System (INIS)

Sugawara-Tanabe, Kazuko; Tanabe, Kosai.

1986-01-01

Microscopic calculations are carried out for the giant dipole resonances excited on the thermal high spin states in 162 Er and 166 Er based on the thermal linear response theory with realistic forces and large single-particle space. The dynamical strength function is compared with the experimental γ-ray absorption cross section. The general trend that the resonance energy decreases and the resonance width increases with increasing angular momentum and temperature is well reproduced by the calculations. (author)

High frequency time modulation of neutrons by LiNbO3 crystals with surface acoustic waves excited under the diffraction condition

International Nuclear Information System (INIS)

Takahashi, Toshio; Granzer, E.; Kikuta, Seishi; Tomimitsu, Hiroshi; Doi, Kenji.

1985-01-01

High frequency time modulation of neutrons was investigated by using Y-cut LiNbO 3 crystals with surface acoustic waves excited. A double crystal arrangement of (+, -) parallel setting was used for 030 symmetric Bragg-case reflections. Synchronized standing waves with a resonance frequency of 14.26 MHz were excited on the both crystals. Variation of the diffracted intensity with phase difference between two standing waves was studied. The result showed an intensity change of diffracted neutrons with twice the resonance frequency. (author)

Study of resonant magnet exciting system for the 3 GeV proton synchrotron

Energy Technology Data Exchange (ETDEWEB)

Koseki, Shoichiro; Zhang, Fengqing; Watanabe, Yasuhiro; Tani, Norio [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Adachi, Toshikazu; Someya, Hirohiko [High Energy Accelerator Research Organization, Tsukuba, Ibaraki (Japan)

2001-07-01

Exciting system for magnets of the 3 GeV Proton synchrotron is under consideration. A resonant exciting system is studied, and two type of power supply are compared. One is a parallel supply that is used generally. Another is a modified series supply. Either of them uses IGBT sinusoidal converters. Capacity of the power converter of the series supply for bending magnets becomes 28.8 MVAp. This is lager more than twice compared with the parallel supply. In the other hand, the series supply has good control performance and flexibility. More study is necessary to decide finally. (author)

Fiber pigtailed thin wall capillary coupler for excitation of microsphere WGM resonator.

Science.gov (United States)

Wang, Hanzheng; Lan, Xinwei; Huang, Jie; Yuan, Lei; Kim, Cheol-Woon; Xiao, Hai

2013-07-01

In this paper, we demonstrate a fiber pigtailed thin wall capillary coupler for excitation of Whispering Gallery Modes (WGMs) of microsphere resonators. The coupler is made by fusion-splicing an optical fiber with a capillary tube and consequently etching the capillary wall to a thickness of a few microns. Light is coupled through the peripheral contact between inserted microsphere and the etched capillary wall. The coupling efficiency as a function of the wall thickness was studied experimentally. WGM resonance with a Q-factor of 1.14 × 10(4) was observed using a borosilicate glass microsphere with a diameter of 71 μm. The coupler operates in the reflection mode and provides a robust mechanical support to the microsphere resonator. It is expected that the new coupler may find broad applications in sensors, optical filters and lasers.

Parallel ferromagnetic resonance and spin-wave excitation in exchange-biased NiFe/IrMn bilayers

Energy Technology Data Exchange (ETDEWEB)

Sousa, Marcos Antonio de, E-mail: marcossharp@gmail.com [Instituto de Física, Universidade Federal de Goiás, Goiânia, 74001-970 (Brazil); Pelegrini, Fernando [Instituto de Física, Universidade Federal de Goiás, Goiânia, 74001-970 (Brazil); Alayo, Willian [Departamento de Física, Universidade Federal de Pelotas, Pelotas, 96010-900 (Brazil); Quispe-Marcatoma, Justiniano; Baggio-Saitovitch, Elisa [Centro Brasileiro de Pesquisas Físicas, Rio de Janeiro, 22290-180 (Brazil)

2014-10-01

Ferromagnetic Resonance study of sputtered Ru(7 nm)/NiFe(t{sub FM})/IrMn(6 nm)/Ru(5 nm) exchange-biased bilayers at X and Q-band microwave frequencies reveals the excitation of spin-wave and NiFe resonance modes. Angular variations of the in-plane resonance fields of spin-wave and NiFe resonance modes show the effect of the unidirectional anisotropy, which is about twice larger for the spin-wave mode due to spin pinning at the NiFe/IrMn interface. At Q-band frequency the angular variations of in-plane resonance fields also reveal the symmetry of a uniaxial anisotropy. A modified theoretical model which also includes the contribution of a rotatable anisotropy provides a good description of the experimental results.

Excited-state structure and electronic dephasing time of Nile blue from absolute resonance Raman intensities

Science.gov (United States)

Lawless, Mary K.; Mathies, Richard A.

1992-06-01

Absolute resonance Raman cross sections are measured for Nile blue 690 perchlorate dissolved in ethylene glycol with excitation at 514, 531, and 568 nm. These values and the absorption spectrum are modeled using a time-dependent wave packet formalism. The excited-state equilibrium geometry changes are quantitated for 40 resonance Raman active modes, seven of which (590, 1141, 1351, 1429, 1492, 1544, and 1640 cm-1 ) carry 70% of the total resonance Raman intensity. This demonstrates that in addition to the prominent 590 and 1640 cm-1 modes, a large number of vibrational degrees of freedom are Franck-Condon coupled to the electronic transition. After exposure of the explicit vibrational progressions, the residual absorption linewidth is separated into its homogeneous [350 cm-1 half-width at half-maximum (HWHM)] and inhomogeneous (313 cm-1 HWHM) components through an analysis of the absolute Raman cross sections. The value of the electronic dephasing time derived from this study (25 fs) compares well to previously published results. These data should be valuable in multimode modeling of femtosecond experiments on Nile blue.

Advances in magnetic resonance 6

CERN Document Server

Waugh, John S

2013-01-01

Advances in Magnetic Resonance, Volume 6 focuses on the theoretical and practical aspects of applying magnetic resonance methods to various problems in physical chemistry, emphasizing the different aspects of the exegesis of these problems. This book discusses the gas phase magnetic resonance of electronically excited molecules; techniques for observing excited electronic states; NMR studies in liquids at high pressure; and effect of pressure on self-diffusion in liquids. The nuclear magnetic resonance investigations of organic free radicals; measurement of proton coupling constants by NMR; an

Dissociative electron attachment to vibrationally excited H2 molecules involving the 2Σg+ resonant Rydberg electronic state

International Nuclear Information System (INIS)

Celiberto, R.; Janev, R.K.; Wadehra, J.M.; Tennyson, J.

2012-01-01

Graphical abstract: Dissociative electron attachment cross sections as a function of the incident electron energy and for the initial vibration levels v i = 0–5, 10 of the H 2 molecule. Highlights: ► We calculated electron–hydrogen dissociative attachment cross sections and rates coefficients. ► Collision processes occurring through a resonant Rydberg state are considered. ► Cross sections and rates were obtained for vibrationally excited hydrogen molecules. ► The cross sections exhibit pronounced oscillatory structures. ► A comparison with the process involving the electron–hydrogen resonant ground state is discussed. - Abstract: Dissociative electron attachment cross sections (DEA) on vibrationally excited H 2 molecule taking place via the 2 Σ g + Rydberg-excited resonant state are studied using the local complex potential (LCP) model for resonant collisions. The cross sections are calculated for all initial vibrational levels (v i = 0–14) of the neutral molecule. In contrast to the previously noted dramatic increase in the DEA cross sections with increasing v i , when the process proceeds via the X 2 Σ u + shape resonance of H 2 , for the 2 Σ g + Rydberg resonance the cross sections increase only gradually up to v i = 3 and then decrease. Moreover, the cross sections for v i ⩾ 6 exhibit pronounced oscillatory structures. A discussion of the origin of the observed behavior of calculated cross sections is given. The DEA rate coefficients for all v i levels are also calculated in the 0.5–1000 eV temperature range.

Possibility of resonant capture of antiprotons by highly charged hydrogenlike ions

International Nuclear Information System (INIS)

Genkin, M.; Lindroth, E.

2009-01-01

Recently, an experimental setup was proposed by Lapierre et al. which would allow antiprotons and highly charged ions to collide repeatedly in an electron beam ion trap (EBIT) due to a nested trap configuration. As mentioned by the authors, such a setup may open the possibility to study antiproton capture into well-defined states through a resonant process which involves simultaneous electron excitation. In the present work, we give some theoretical estimations of the feasibility of that process. It appears that the exotic dielectronic-like process of resonant anti-proton capture in highly charged ions does not seem to be completely out of reach

RESONANT POST-NEWTONIAN ECCENTRICITY EXCITATION IN HIERARCHICAL THREE-BODY SYSTEMS

Energy Technology Data Exchange (ETDEWEB)

Naoz, Smadar; Kocsis, Bence; Loeb, Abraham [Institute for Theory and Computation, Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Yunes, Nicolas, E-mail: snaoz@cfa.harvard.edu [Department of Physics, Montana State University, Bozeman, MT 59718 (United States)

2013-08-20

We study the secular, hierarchical three-body problem to first-order in a post-Newtonian expansion of general relativity (GR). We expand the first-order post-Newtonian Hamiltonian to leading-order in the ratio of the semi-major axis of the two orbits. In addition to the well-known terms that correspond to the GR precession of the inner and outer orbits, we find a new secular post-Newtonian interaction term that can affect the long-term evolution of the triple. We explore the parameter space for highly inclined and eccentric systems, where the Kozai-Lidov mechanism can produce large-amplitude oscillations in the eccentricities. The standard lore, i.e., that GR effects suppress eccentricity, is only consistent with the parts of phase space where the GR timescales are several orders of magnitude shorter than the secular Newtonian one. In other parts of phase space, however, post-Newtonian corrections combined with the three-body ones can excite eccentricities. In particular, for systems where the GR timescale is comparable to the secular Newtonian timescales, the three-body interactions give rise to a resonant-like eccentricity excitation. Furthermore, for triples with a comparable-mass inner binary, where the eccentric Kozai-Lidov mechanism is suppressed, post-Newtonian corrections can further increase the eccentricity and lead to orbital flips even when the timescale of the former is much longer than the timescale of the secular Kozai-Lidov quadrupole perturbations.

Resonance effects in projectile-electron loss in relativistic collisions with excited atoms

International Nuclear Information System (INIS)

Voitkiv, A B

2005-01-01

The theory of electron loss from projectile-ions in relativistic ion-atom collisions is extended to the case of collisions with excited atoms. The main feature of such collisions is a resonance which can emerge between electron transitions in the ion and atom. The resonance becomes possible due to the Doppler effect and has a well-defined impact energy threshold. In the resonance case, the ion-atom interaction is transmitted by the radiation field and the range of this interaction becomes extremely long. Because of this the presence of other atoms in the target medium and the size of the space occupied by the medium have to be taken into account and it turns out that microscopic loss cross sections may be strongly dependent on such macroscopic parameters as the target density, temperature and size. We consider both the total and differential loss cross sections and show that the resonance can have a strong impact on the angular and energy distributions of electrons emitted from the projectiles and the total number of electron loss events

Nano-polarization-converter based on magnetic plasmon resonance excitation in an L-shaped slot antenna.

Science.gov (United States)

Yang, Jing; Zhang, Jiasen

2013-04-08

We propose a nano-polarization-converter made of a resonant L-shaped slot antenna in a gold film and study its optical properties using the finite-difference time-domain method. Phase retardation between the fast and slow axes of the nano-polarization-converter originates from the simultaneous excitation of both single-surface first-order magnetic plasmon resonance mode and second-order magnetic plasmon resonance mode at the working wavelength. By adjusting the size of the slot antenna, which is still much smaller than the wavelength, the working wavelength can be tuned within a large wavelength range.

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

Excitation of the giant resonance in the radiative pion capture on lp shell nuclei

International Nuclear Information System (INIS)

Dogotar', G.E.

1978-01-01

The spin-dipole transitions in the (π - ,γ) reaction on 6 Li, 7 Li, 9 Be, 13 C and 14 N are calculated in the framework of shell model and are compared with experiment. The discussion includes the gross structure and the quantum numbers of the resonance, relative branchings, prominent partial transitions and total yields. General findings is that the calculated (π - ,γ) yield distributions describe the data well in those cases where also the photonuclear data are well reproduced, although the amplitudes of the elementary processes are different. In the case considered, the best agreement is obtained for A=9 and 14. The configurational splitting of the resonances is clearly seen in the A=6 and 7 cases, to somewhat less extent also for A=9. For heavier nuclei the contribution from hole excitation is small and is spread out. For A=7 and 11 the calculated main peaks are at too low intrinsic excitation energies as compared with histograms

Calculation of a CO sub 2 gasdynamic laser with selective thermal excitation and an unstable resonator

Energy Technology Data Exchange (ETDEWEB)

Kuz' min, A.I.; Lavrov, A.V.; Chernysheva, N.V. (Leningradskii Gosudarstvennyi Universitet, Leningrad (USSR))

1989-03-01

The problem of calculating an unstable telescopic resonator for a CO{sub 2} gasdynamic laser with selective thermal excitation is studied. Parabolized Navier-Stokes equations and equations of field propagation in the resonator are used to describe the GDL in the geometric optic approximation. The efficiency is studied as a function of the magnification factor and of the distance between the mirrors. 19 refs.

Angular distribution of hypersatellite and satellite radiation emitted after resonant and excitation into $U^{91+}$ ions

CERN Document Server

Zakowicz, S; Harman, Z; Scheid, W

2003-01-01

In collisions of heavy few-electron projectile ions with light targets, an electron can be transferred from the target with the simultaneous excitation of a projectile electron. We study the angular distribution of de-excitation X rays following the resonant capture process. Our results are compared to experimental values of Ma et al. [Phys. Rev. A (joint to this issue)] for collisions of U91+ ions with a hydrogen gas target.

Resonant Tidal Excitation of Internal Waves in the Earth's Fluid Core

Science.gov (United States)

Tyler, Robert H.; Kuang, Weijia

2014-01-01

It has long been speculated that there is a stably stratified layer below the core-mantle boundary, and two recent studies have improved the constraints on the parameters describing this stratification. Here we consider the dynamical implications of this layer using a simplified model. We first show that the stratification in this surface layer has sensitive control over the rate at which tidal energy is transferred to the core. We then show that when the stratification parameters from the recent studies are used in this model, a resonant configuration arrives whereby tidal forces perform elevated rates of work in exciting core flow. Specifically, the internal wave speed derived from the two independent studies (150 and 155 m/s) are in remarkable agreement with the speed (152 m/s) required for excitation of the primary normal mode of oscillation as calculated from full solutions of the Laplace Tidal Equations applied to a reduced-gravity idealized model representing the stratified layer. In evaluating this agreement it is noteworthy that the idealized model assumed may be regarded as the most reduced representation of the stratified dynamics of the layer, in that there are no non-essential dynamical terms in the governing equations assumed. While it is certainly possible that a more realistic treatment may require additional dynamical terms or coupling, it is also clear that this reduced representation includes no freedom for coercing the correlation described. This suggests that one must accept either (1) that tidal forces resonantly excite core flow and this is predicted by a simple model or (2) that either the independent estimates or the dynamical model does not accurately portray the core surface layer and there has simply been an unlikely coincidence between three estimates of a stratification parameter which would otherwise have a broad plausible range.

Non linear excitation of waves at the vicinity of plasma resonance

International Nuclear Information System (INIS)

Chiron, Arnaud

1992-01-01

This research thesis reports the study of the non linear evolution of ionic acoustic and plasma waves excited by resonant absorption of an electromagnetic wave, in a non collisional plasma, without external magnetic field, and with a parabolic density profile. The plasma resonance occurs about the density profile peak. The numerical resolution of the Zakharov equation system is performed to describe the coupled evolution of the plasma wave electric field envelope, and low frequency density disturbances. Experiments performed in the microwave domain show the existence of a new effect related to the modification of the electromagnetic wave propagation under the influence of plasma density disturbances created by the ponderomotive force. This effect which results in a collisional relaxation of plasma waves trapped in the cavity formed at resonance, cannot be taken into account by a numerical simulation using a capacitive pump field. Measurements showed that plasma waves were trapped and relaxing in a cavity with characteristic dimensions of some thousands of Debye lengths, and that the plasma wave in the cavity was stationary. A new turbulence regime is thus highlighted [fr

Electron Dynamics in the Core-Excited CS 2 Molecule Revealed through Resonant Inelastic X-Ray Scattering Spectroscopy

OpenAIRE

Marchenko , T; Carniato , S; Journel , L; Guillemin , R; Kawerk , E; Žitnik , M; Kavčič , M; Bučar , K; Bohinc , R; Petric , M; Vaz Da Cruz , V; Gel 'mukhanov , F; Simon , Marielle

2015-01-01

International audience; We present an experimental and theoretical study of resonant inelastic x-ray scattering (RIXS) in the carbon disulphide CS 2 molecule near the sulfur K-absorption edge. We observe a strong evolution of the RIXS spectral profile with the excitation energy tuned below the lowest unoccupied molecular orbital (LUMO) absorption resonance. The reason for this is twofold. Reducing the photon energy in the vicinity of the LUMO absorption resonance leads to a relative suppressi...

Computer screen photo-excited surface plasmon resonance imaging.

Science.gov (United States)

Filippini, Daniel; Winquist, Fredrik; Lundström, Ingemar

2008-09-12

Angle and spectra resolved surface plasmon resonance (SPR) images of gold and silver thin films with protein deposits is demonstrated using a regular computer screen as light source and a web camera as detector. The screen provides multiple-angle illumination, p-polarized light and controlled spectral radiances to excite surface plasmons in a Kretchmann configuration. A model of the SPR reflectances incorporating the particularities of the source and detector explain the observed signals and the generation of distinctive SPR landscapes is demonstrated. The sensitivity and resolution of the method, determined in air and solution, are 0.145 nm pixel(-1), 0.523 nm, 5.13x10(-3) RIU degree(-1) and 6.014x10(-4) RIU, respectively, encouraging results at this proof of concept stage and considering the ubiquity of the instrumentation.

Evolution of spin excitations in a gapped antiferromagnet from the quantum to the high-temperature limit

DEFF Research Database (Denmark)

Kenzelmann, M.; Cowley, R.A.; Buyers, W.J.L.

2002-01-01

We have mapped from the quantum to the classical limit the spin excitation spectrum of the antiferromagnetic spin-1 Heisenberg chain system CsNiCl3 in its paramagnetic phase from T=5 to 200 K. Neutron scattering shows that the excitations are resonant and dispersive up to at least T=70 Ksimilar...... is in agreement with quantum Monte Carlo calculations for the spin-1 chain. xi is also consistent with the single mode approximation, suggesting that the excitations are short-lived single particle excitations. Below T=12 K where three-dimensional spin correlations are important, xi is shorter than predicted...... and the experiment is not consistent with the random phase approximation for coupled quantum chains. At T=200 K, the structure factor and second energy moment of the excitation spectrum are in excellent agreement with the high-temperature series expansion....

The CLAS Excited Baryon Program at Jefferson Laboratory

International Nuclear Information System (INIS)

Crede, Volker

2009-01-01

Nucleons are complex systems of confined quarks and exhibit characteristic spectra of excited states. Highly excited nucleon states are sensitive to details of quark confinement which is poorly understood within Quantum Chromodynamics (QCD), the fundamental theory of strong interactions. Thus, measurements of excited states and the corresponding determination of their properties are needed to come to a better understanding of how confinement works in nucleons. However, the excited states of the nucleon cannot simply be inferred from cleanly separated spectral lines. Quite the contrary, a spectral analysis in nucleon resonance physics is challenging because of the fact that the resonances are broadly overlapping states which decay into a multitude of final states involving mesons and baryons. To provide a consistent and complete picture of an individual nucleon resonance, the various possible production and decay channels must be treated in a multi-channel framework that permits separat

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.

Plasma heating in multiple-resonance excitation of a plasma in a mirror machine

Energy Technology Data Exchange (ETDEWEB)

Bender, A; Siambis, J G [Carnegie-Mellon Univ., Pittsburgh, Pa. (USA)

1976-06-01

By applying 1 kW of microwave power at 2.45 GHz and 1 kW of r.f. power in the frequency range of 4-25 MHz at one end of a mirror machine, where neutral hydrogen gas is injected in a pulsed mode, a plasma density of 2 x 10/sup 11/cm/sup -3/ with an electron temperature of 60 eV and ion temperature of 40 eV is generated. The ion heating mechanism, is, principally, collisional thermalization of the applied r.f. power, via coupling to and excitation of the low frequency resonances of the plasma column, in agreement with the theoretical prediction for the case of high total effective collision frequency for momentum transfer for the electrons.

Electron cloud density measurements in accelerator beam-pipe using resonant microwave excitation

Energy Technology Data Exchange (ETDEWEB)

Sikora, John P., E-mail: jps13@cornell.edu [CLASSE, Cornell University, Ithaca, NY 14853 (United States); Carlson, Benjamin T. [Carnegie Mellon University, Pittsburgh, PA 15213 (United States); Duggins, Danielle O. [Gordon College, Wenham, MA 01984 (United States); Hammond, Kenneth C. [Columbia University, New York, NY 10027 (United States); De Santis, Stefano [LBNL, Berkeley, CA 94720 (United States); Tencate, Alister J. [Idaho State University, Pocatello, ID 83209 (United States)

2014-08-01

An accelerator beam can generate low energy electrons in the beam-pipe, generally called electron cloud, that can produce instabilities in a positively charged beam. One method of measuring the electron cloud density is by coupling microwaves into and out of the beam-pipe and observing the response of the microwaves to the presence of the electron cloud. In the original technique, microwaves are transmitted through a section of beam-pipe and a change in EC density produces a change in the phase of the transmitted signal. This paper describes a variation on this technique in which the beam-pipe is resonantly excited with microwaves and the electron cloud density calculated from the change that it produces in the resonant frequency of the beam-pipe. The resonant technique has the advantage that measurements can be localized to sections of beam-pipe that are a meter or less in length with a greatly improved signal to noise ratio.

Charge-transfer and Mott-Hubbard Excitations in FeBo3: Fe K-edge resonant Inelastic x-ray scattering study

International Nuclear Information System (INIS)

Kim, J.; Shvydko, Y.

2011-01-01

Momentum-resolved resonant inelastic x-ray scattering (RIXS) spectroscopy has been carried out successfully at the Fe K-edge for the first time. The RIXS spectra of a FeBO 3 single crystal reveal a wealth of information on ∼ 1-10 eV electronic excitations. The IXS signal resonates when the incident photon energy approaches the pre-edge (1s - -3d) and the main-edge (1s - -4p) of the Fe K-edge absorption spectrum. The RIXS spectra measured at the pre-edge and the main-edge show quantitatively different dependences on the incident photon energy, momentum transfer, photon polarization, and temperature. We present a multielectron analysis of the Mott-Hubbard (MH) and charge transfer (CT) excitations, and calculate their energies. Electronic excitations observed in the pre-edge and main-edge RIXS spectra are interpreted as MH and CT excitations, respectively. We propose the electronic structure around the chemical potential in FeBO 3 based on the experimental data.

Plasma diagnostics using laser-excited coupled and transmission ring resonators

International Nuclear Information System (INIS)

Haas, R.A.

1976-01-01

In this paper a simple two-level laser model is used to investigate the frequency response of coupled-cavity laser interferometers. It is found that under certain circumstances, often satisfied by molecular gas lasers, the frequency response exhibits a resonant behavior. This behavior severely complicates the interpretation of coupled-cavity laser interferometer measurements of rapidly varying plasmas. To circumvent this limitation a new type of laser interferometer plasma diagnostic with significantly improved time response was developed. In this interferometer the plasma is located in one arm of a transmission ring resonator cavity that is excited by an externally positioned laser. Thus, the laser is decoupled from the interferometer cavity and the time response of the interferometer is then limited by the Q of the ring resonator cavity. This improved time response is acquired without loss of spatial resolution, but requires a more sensitive signal detector since the laser is no longer used as a detector as it is in conventional coupled-cavity laser interferometers. Thus, the new technique incorporates the speed of the Mach--Zender interferometer and the sensitivity of the coupled-cavity laser interferometer. The basic operating principles of this type of interferometer have been verified using a CO 2 laser

Two-particle excitations in the Hubbard model for high-temperature superconductors. A quantum cluster study

International Nuclear Information System (INIS)

Brehm, Sascha

2009-01-01

Two-particle excitations, such as spin and charge excitations, play a key role in high-T c cuprate superconductors (HTSC). Due to the antiferromagnetism of the parent compound the magnetic excitations are supposed to be directly related to the mechanism of superconductivity. In particular, the so-called resonance mode is a promising candidate for the pairing glue, a bosonic excitation mediating the electronic pairing. In addition, its interactions with itinerant electrons may be responsible for some of the observed properties of HTSC. Hence, getting to the bottom of the resonance mode is crucial for a deeper understanding of the cuprate materials. To analyze the corresponding two-particle correlation functions we develop in the present thesis a new, non-perturbative and parameter-free technique for T=0 which is based on the Variational Cluster Approach (VCA, an embedded cluster method for one-particle Green's functions). Guided by the spirit of the VCA we extract an effective electron-hole vertex from an isolated cluster and use a fully renormalized bubble susceptibility χ 0 including the VCA one-particle propagators. Within our new approach, the magnetic excitations of HTSC are shown to be reproduced for the Hubbard model within the relevant strong-coupling regime. Exceptionally, the famous resonance mode occurring in the underdoped regime within the superconductivity-induced gap of spin-flip electron-hole excitations is obtained. Its intensity and hourglass dispersion are in good overall agreement with experiments. Furthermore, characteristic features such as the position in energy of the resonance mode and the difference of the imaginary part of the susceptibility in the superconducting and the normal states are in accord with Inelastic Neutron Scattering (INS) experiments. For the first time, a strongly-correlated parameter-free calculation revealed these salient magnetic properties supporting the S=1 magnetic exciton scenario for the resonance mode. Besides

X-ray excited photoluminescence near the giant resonance in solid-solution Gd1-xTbxOCl nanocrystals and their retention upon solvothermal topotactic transformation to Gd1-xTbxF3

Science.gov (United States)

Waetzig, Gregory R.; Horrocks, Gregory A.; Jude, Joshua W.; Zuin, Lucia; Banerjee, Sarbajit

2015-12-01

Design rules for X-ray phosphors are much less established as compared to their optically stimulated counterparts owing to the absence of a detailed understanding of sensitization mechanisms, activation pathways and recombination channels upon high-energy excitation. Here, we demonstrate a pronounced modulation of the X-ray excited photoluminescence of Tb3+ centers upon excitation in proximity to the giant resonance of the host Gd3+ ions in solid-solution Gd1-xTbxOCl nanocrystals prepared by a non-hydrolytic cross-coupling method. The strong suppression of X-ray excited optical luminescence at the giant resonance suggests a change in mechanism from multiple exciton generation to single thermal exciton formation and Auger decay processes. The solid-solution Gd1-xTbxOCl nanocrystals are further topotactically transformed with retention of a nine-coordinated cation environment to solid-solution Gd1-xTbxF3 nanocrystals upon solvothermal treatment with XeF2. The metastable hexagonal phase of GdF3 can be stabilized at room temperature through this topotactic approach and is transformed subsequently to the orthorhombic phase. The fluoride nanocrystals indicate an analogous but blue-shifted modulation of the X-ray excited optical luminescence of the Tb3+ centers upon X-ray excitation near the giant resonance of the host Gd3+ ions.Design rules for X-ray phosphors are much less established as compared to their optically stimulated counterparts owing to the absence of a detailed understanding of sensitization mechanisms, activation pathways and recombination channels upon high-energy excitation. Here, we demonstrate a pronounced modulation of the X-ray excited photoluminescence of Tb3+ centers upon excitation in proximity to the giant resonance of the host Gd3+ ions in solid-solution Gd1-xTbxOCl nanocrystals prepared by a non-hydrolytic cross-coupling method. The strong suppression of X-ray excited optical luminescence at the giant resonance suggests a change in mechanism

Charge-resonance excitations in symmetric molecules - Comparison of linear response DFT with CC3 for the excited states of a model dimer

DEFF Research Database (Denmark)

Kuhlman, Thomas Scheby; Mikkelsen, Kurt V.; Møller, Klaus Braagaard

2009-01-01

to a reference CC3 calculation revealing a better description of the excited states by CAM-B3LYP than that of B3LYP. The Λ parameter introduced by Peach et al. [M.J.G. Peach, P. Benfield, T. Helgaker, D.J. Tozer, J. Chem. Phys. 128 (2008) 044118] does not always reveal the problematic charge-resonance states...

Broadband non-selective excitation of plutonium isotopes for isotope ratio measurements in resonance ionization mass spectrometry: a theoretical study.

Science.gov (United States)

Sankari, M

2012-10-15

Making isotope ratio measurements with minimum isotope bias has always been a challenging task to mass spectrometrists, especially for the specific case of plutonium, owing to the strategic importance of the element. In order to use resonance ionization mass spectrometry (RIMS) as a tool for isotope ratio measurements, optimization of the various laser parameters and other atomic and system parameters is critical to minimize isotopic biases. Broadband simultaneous non-selective excitation of the isotopes of plutonium in the triple resonance excitation scheme with λ(1) = 420.77 nm, λ(2) = 847.28 nm, and λ(3) = 767.53 nm based on density matrix formalism has been theoretically computed for the determination of isotope ratios. The effects of the various laser parameters and other factors such as the atomization temperature and the dimensions of the atomic beam on the estimation of isotope ratios were studied. The effects of Doppler broadening, and time-dependent excitation parameters such as Rabi frequencies, ionization rate and the effect of non-Lorenztian lineshape have all been incorporated. The average laser powers and bandwidths for the three-excitation steps were evaluated for non-selective excitation. The laser intensity required to saturate the three-excitation steps were studied. The two-dimensional lineshape contour and its features were investigated, while the reversal of peak asymmetry of two-step and two-photon excitation peaks under these conditions is discussed. Optimized powers for the non-selective ionization of the three transitions were calculated as 545 mW, 150 mW and 545 mW and the laser bandwidth for all the three steps was ~20 GHz. The isotopic bias between the resonant and off-resonant isotope under the optimized conditions was no more than 9%, which is better than an earlier reported value. These optimized laser power and bandwidth conditions are better than in the earlier experimental work since these comprehensive calculations yield

Electrode-shaping for the excitation and detection of permitted arbitrary modes in arbitrary geometries in piezoelectric resonators.

Science.gov (United States)

Pulskamp, Jeffrey S; Bedair, Sarah S; Polcawich, Ronald G; Smith, Gabriel L; Martin, Joel; Power, Brian; Bhave, Sunil A

2012-05-01

This paper reports theoretical analysis and experimental results on a numerical electrode shaping design technique that permits the excitation of arbitrary modes in arbitrary geometries for piezoelectric resonators, for those modes permitted to exist by the nonzero piezoelectric coefficients and electrode configuration. The technique directly determines optimal electrode shapes by assessing the local suitability of excitation and detection electrode placement on two-port resonators without the need for iterative numerical techniques. The technique is demonstrated in 61 different electrode designs in lead zirconate titanate (PZT) thin film on silicon RF micro electro-mechanical system (MEMS) plate, beam, ring, and disc resonators for out-of-plane flexural and various contour modes up to 200 MHz. The average squared effective electromechanical coupling factor for the designs was 0.54%, approximately equivalent to the theoretical maximum value of 0.53% for a fully electroded length-extensional mode beam resonator comprised of the same composite. The average improvement in S(21) for the electrode-shaped designs was 14.6 dB with a maximum improvement of 44.3 dB. Through this piezoelectric electrodeshaping technique, 95% of the designs showed a reduction in insertion loss.

MEMS Logic Using Mixed-Frequency Excitation

KAUST Repository

Ilyas, Saad

2017-06-22

We present multi-function microelectromechanical systems (MEMS) logic device that can perform the fundamental logic gate AND, OR, universal logic gates NAND, NOR, and a tristate logic gate using mixed-frequency excitation. The concept is based on exciting combination resonances due to the mixing of two or more input signals. The device vibrates at two steady states: a high state when the combination resonance is activated and a low state when no resonance is activated. These vibration states are assigned to logical value 1 or 0 to realize the logic gates. Using ac signals to drive the resonator and to execute the logic inputs unifies the input and output wave forms of the logic device, thereby opening the possibility for cascading among logic devices. We found that the energy consumption per cycle of the proposed logic resonator is higher than those of existing technologies. Hence, integration of such logic devices to build complex computational system needs to take into consideration lowering the total energy consumption. [2017-0041

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

Study of orbitally excited $B$ mesons and evidence for a new $B\\pi$ resonance

CERN Document Server

Aaltonen, Timo Antero; Amidei, Dante E; Anastassov, Anton Iankov; Annovi, Alberto; Antos, Jaroslav; Apollinari, Giorgio; Appel, Jeffrey A; Arisawa, Tetsuo; Artikov, Akram Muzafarovich; Asaadi, Jonathan A; Ashmanskas, William Joseph; Auerbach, Benjamin; Aurisano, Adam J; Azfar, Farrukh A; Badgett, William Farris; Bae, Taegil; Barbaro-Galtieri, Angela; Barnes, Virgil E; Barnett, Bruce Arnold; Barria, Patrizia; Bartos, Pavol; Bauce, Matteo; Bedeschi, Franco; Behari, Satyajit; Bellettini, Giorgio; Bellinger, James Nugent; Benjamin, Douglas P; Beretvas, Andrew F; Bhatti, Anwar Ahmad; Bland, Karen Renee; Blumenfeld, Barry J; Bocci, Andrea; Bodek, Arie; Bortoletto, Daniela; Boudreau, Joseph Francis; Boveia, Antonio; Brigliadori, Luca; Bromberg, Carl Michael; Brucken, Erik; Budagov, Ioulian A; Budd, Howard Scott; Burkett, Kevin Alan; Busetto, Giovanni; Bussey, Peter John; Butti, Pierfrancesco; Buzatu, Adrian; Calamba, Aristotle; Camarda, Stefano; Campanelli, Mario; Canelli, Florencia; Carls, Benjamin; Carlsmith, Duncan L; Carosi, Roberto; Carrillo Moreno, Salvador; Casal Larana, Bruno; Casarsa, Massimo; Castro, Andrea; Catastini, Pierluigi; Cauz, Diego; Cavaliere, Viviana; Cavalli-Sforza, Matteo; Cerri, Alessandro; Cerrito, Lucio; Chen, Yen-Chu; Chertok, Maxwell Benjamin; Chiarelli, Giorgio; Chlachidze, Gouram; Cho, Kihyeon; Chokheli, Davit; Clark, Allan Geoffrey; Clarke, Christopher Joseph; Convery, Mary Elizabeth; Conway, John Stephen; Corbo, Matteo; Cordelli, Marco; Cox, Charles Alexander; Cox, David Jeremy; Cremonesi, Matteo; Cruz Alonso, Daniel; Cuevas Maestro, Javier; Culbertson, Raymond Lloyd; D'Ascenzo, Nicola; Datta, Mousumi; de Barbaro, Pawel; Demortier, Luc M; Marchese, Luigi; Deninno, Maria Maddalena; Devoto, Francesco; D'Errico, Maria; Di Canto, Angelo; Di Ruzza, Benedetto; Dittmann, Jay Richard; D'Onofrio, Monica; Donati, Simone; Dorigo, Mirco; Driutti, Anna; Ebina, Koji; Edgar, Ryan Christopher; Elagin, Andrey L; Erbacher, Robin D; Errede, Steven Michael; Esham, Benjamin; Farrington, Sinead Marie; Feindt, Michael; Fernández Ramos, Juan Pablo; Field, Richard D; Flanagan, Gene U; Forrest, Robert David; Franklin, Melissa EB; Freeman, John Christian; Frisch, Henry J; Funakoshi, Yujiro; Galloni, Camilla; Garfinkel, Arthur F; Garosi, Paola; Gerberich, Heather Kay; Gerchtein, Elena A; Giagu, Stefano; Giakoumopoulou, Viktoria Athina; Gibson, Karen Ruth; Ginsburg, Camille Marie; Giokaris, Nikos D; Giromini, Paolo; Giurgiu, Gavril A; Glagolev, Vladimir; Glenzinski, Douglas Andrew; Gold, Michael S; Goldin, Daniel; Golossanov, Alexander; Gomez, Gervasio; Gomez-Ceballos, Guillelmo; Goncharov, Maxim T; González López, Oscar; Gorelov, Igor V; Goshaw, Alfred T; Goulianos, Konstantin A; Gramellini, Elena; Grinstein, Sebastian; Grosso-Pilcher, Carla; Group, Robert Craig; Barreiro Guimaraes da Costa, Joao; Hahn, Stephen R; Han, Ji-Yeon; Happacher, Fabio; Hara, Kazuhiko; Hare, Matthew Frederick; Harr, Robert Francis; Harrington-Taber, Timothy; Hatakeyama, Kenichi; Hays, Christopher Paul; Heinrich, Joel G; Herndon, Matthew Fairbanks; Hocker, James Andrew; Hong, Ziqing; Hopkins, Walter Howard; Hou, Suen Ray; Hughes, Richard Edward; Husemann, Ulrich; Hussein, Mohammad; Huston, Joey Walter; Introzzi, Gianluca; Iori, Maurizio; Ivanov, Andrew Gennadievich; James, Eric B; Jang, Dongwook; Jayatilaka, Bodhitha Anjalike; Jeon, Eun-Ju; Jindariani, Sergo Robert; Jones, Matthew T; Joo, Kyung Kwang; Jun, Soon Yung; Junk, Thomas R; Kambeitz, Manuel; Kamon, Teruki; Karchin, Paul Edmund; Kasmi, Azeddine; Kato, Yukihiro; Ketchum, Wesley Robert; Keung, Justin Kien; Kilminster, Benjamin John; Kim, DongHee; Kim, Hyunsoo; Kim, Jieun; Kim, Min Jeong; Kim, Soo Bong; Kim, Shin-Hong; Kim, Young-Kee; Kim, Young-Jin; Kimura, Naoki; Kirby, Michael H; Knoepfel, Kyle James; Kondo, Kunitaka; Kong, Dae Jung; Konigsberg, Jacobo; Kotwal, Ashutosh Vijay; Kreps, Michal; Kroll, IJoseph; Kruse, Mark Charles; Kuhr, Thomas; Kurata, Masakazu; Laasanen, Alvin Toivo; Lammel, Stephan; Lancaster, Mark; Lannon, Kevin Patrick; Latino, Giuseppe; Heck, Martin; Lee, Hyun Su; Lee, Jaison; Leo, Sabato; Leone, Sandra; Lewis, Jonathan D; Limosani, Antonio; Lipeles, Elliot David; Lister, Alison; Liu, Hao; Liu, Qiuguang; Liu, Tiehui Ted; Lockwitz, Sarah E; Loginov, Andrey Borisovich; Lucà, Alessandra; Lucchesi, Donatella; Lueck, Jan; Lujan, Paul Joseph; Lukens, Patrick Thomas; Lungu, Gheorghe; Lys, Jeremy E; Lysak, Roman; Madrak, Robyn Leigh; Maestro, Paolo; Malik, Sarah Alam; Manca, Giulia; Manousakis-Katsikakis, Arkadios; Margaroli, Fabrizio; Marino, Christopher Phillip; Martínez-Perez, Mario; Matera, Keith; Mattson, Mark Edward; Mazzacane, Anna; Mazzanti, Paolo; McNulty, Ronan; Mehta, Andrew; Mehtala, Petteri; Mesropian, Christina; Miao, Ting; Mietlicki, David John; Mitra, Ankush; Miyake, Hideki; Moed, Shulamit; Moggi, Niccolo; Moon, Chang-Seong; Moore, Ronald Scott; Morello, Michael Joseph; Mukherjee, Aseet; Muller, Thomas; Murat, Pavel A; Mussini, Manuel; Nachtman, Jane Marie; Nagai, Yoshikazu; Naganoma, Junji; Nakano, Itsuo; Napier, Austin; Nett, Jason Michael; Neu, Christopher Carl; Nigmanov, Turgun S; Nodulman, Lawrence J; Noh, Seoyoung; Norniella Francisco, Olga; Oakes, Louise Beth; Oh, Seog Hwan; Oh, Young-do; Oksuzian, Iuri Artur; Okusawa, Toru; Orava, Risto Olavi; Ortolan, Lorenzo; Pagliarone, Carmine Elvezio; Palencia, Jose Enrique; Palni, Prabhakar; Papadimitriou, Vaia; Parker, William Chesluk; Pauletta, Giovanni; Paulini, Manfred; Paus, Christoph Maria Ernst; Phillips, Thomas J; Piacentino, Giovanni M; Pianori, Elisabetta; Pilot, Justin Robert; Pitts, Kevin T; Plager, Charles; Pondrom, Lee G; Poprocki, Stephen; Potamianos, Karolos Jozef; Prokoshin, Fedor; Pranko, Aliaksandr Pavlovich; Ptohos, Fotios K; Punzi, Giovanni; Ranjan, Niharika; Redondo Fernández, Ignacio; Renton, Peter B; Rescigno, Marco; Rimondi, Franco; Ristori, Luciano; Robson, Aidan; Rodriguez, Tatiana Isabel; Rolli, Simona; Ronzani, Manfredi; Roser, Robert Martin; Rosner, Jonathan L; Ruffini, Fabrizio; Ruiz Jimeno, Alberto; Russ, James S; Rusu, Vadim Liviu; Sakumoto, Willis Kazuo; Sakurai, Yuki; Santi, Lorenzo; Sato, Koji; Saveliev, Valeri; Savoy-Navarro, Aurore; Schlabach, Philip; Schmidt, Eugene E; Schwarz, Thomas A; Scodellaro, Luca; Scuri, Fabrizio; Seidel, Sally C; Seiya, Yoshihiro; Semenov, Alexei; Sforza, Federico; Shalhout, Shalhout Zaki; Shears, Tara G; Shepard, Paul F; Shimojima, Makoto; Shochet, Melvyn J; Tecker-Shreyber, Irina; Simonenko, Alexander V; Sliwa, Krzysztof Jan; Smith, John Rodgers; Snider, Frederick Douglas; Sorin, Maria Veronica; Song, Hao; Stancari, Michelle Dawn; St Denis, Richard Dante; Stentz, Dale James; Strologas, John; Sudo, Yuji; Sukhanov, Alexander I; Suslov, Igor M; Takemasa, Ken-ichi; Takeuchi, Yuji; Tang, Jian; Tecchio, Monica; Teng, Ping-Kun; Thom, Julia; Thomson, Evelyn Jean; Thukral, Vaikunth; Toback, David A; Tokar, Stanislav; Tollefson, Kirsten Anne; Tomura, Tomonobu; Tonelli, Diego; Torre, Stefano; Torretta, Donatella; Totaro, Pierluigi; Trovato, Marco; Ukegawa, Fumihiko; Uozumi, Satoru; Vázquez-Valencia, Elsa Fabiola; Velev, Gueorgui; Vellidis, Konstantinos; Vernieri, Caterina; Vidal Marono, Miguel; Vilar Cortabitarte, Rocio; Vizán Garcia, Jesus Manuel; Vogel, Marcelo; Volpi, Guido; Wagner, Peter; Wallny, Rainer S; Wang, Song-Ming; Waters, David S; Wester, William Carl; Whiteson, Daniel O; Wicklund, Arthur Barry; Wilbur, Scott; Williams, Hugh H; Wilson, Jonathan Samuel; Wilson, Peter James; Winer, Brian L; Wittich, Peter; Wolbers, Stephen A; Wolfe, Homer; Wright, Thomas Roland; Wu, Xin; Wu, Zhenbin; Yamamoto, Kazuhiro; Yamato, Daisuke; Yang, Tingjun; Yang, Un-Ki; Yang, Yu Chul; Yao, Wei-Ming; Yeh, Gong Ping; Yi, Kai; Yoh, John; Yorita, Kohei; Yoshida, Takuo; Yu, Geum Bong; Yu, Intae; Zanetti, Anna Maria; Zeng, Yu; Zhou, Chen; Zucchelli, Stefano

2014-07-28

Using the full CDF Run II data sample, we report evidence for a new resonance, which we refer to as B(5970), found simultaneously in the $B^0\\pi^+$ and $B^+\\pi^-$ mass distributions with a significance of 4.4 standard deviations. We further report the first study of resonances consistent with orbitally excited $B^{+}$ mesons and an updated measurement of the properties of orbitally excited $B^0$ and $B_s^0$ mesons. Using samples of approximately 8400 $B^{**0}$, 3300 $B^{**+}$, 1350 $B^{**0}_s$, 2600 $B(5970)^0$, and 1400 $B(5970)^+$ decays, we measure the masses and widths of all states, as well as the product of the relative production rate of $B_1$ and $B_2^*$ states times the branching fraction into a $B^{0,+}$ meson and a charged particle. Furthermore, we measure the branching fraction of the $B_{s2}^{*0} \\rightarrow B^{*+} K^-$ decay relative to the $B_{s2}^{*0} \\rightarrow B^{+} K^-$ decay, the production rate times the branching fraction of the B(5970) state relative to the $B_{2}^{*0,+}$ state, and th...

Microwave oscillator with 'whispering gallery' resonator

International Nuclear Information System (INIS)

Kirichenko, A.Ya.; Prokopenko, Yu.V.; Filippov, Yu.F.; Lonin, Yu.F.; Papkovich, V.G.; Ponomarev, A.G.; Prokopenko, Yu.V.; Uvarov, V.T.

2010-01-01

It was presented researches of a generation of microwave radiation into system with azimuthally periodical relativistic electron beam current that excites a high-Q quasi-optical dielectric resonator. The Eigen parameters of cylindrical Teflon resonator were determined by numerical computation. Registration of the microwave radiation realizes by a crystal set of 8-mm wavelength range. Research projects of microwave oscillators with high-Q resonators, in which 'whispering gallery' oscillations are excited by an electron flow, are presented. Multiresonator oscillators ideology is based on principles of microwave generation in klystrons with both subcritical and supercritical electron beams currents.

Traveling Wave Resonance and Simplified Analysis Method for Long-Span Symmetrical Cable-Stayed Bridges under Seismic Traveling Wave Excitation

Directory of Open Access Journals (Sweden)

Zhong-ye Tian

2014-01-01

Full Text Available The seismic responses of a long-span cable-stayed bridge under uniform excitation and traveling wave excitation in the longitudinal direction are, respectively, computed. The numerical results show that the bridge’s peak seismic responses vary significantly as the apparent wave velocity decreases. Therefore, the traveling wave effect must be considered in the seismic design of long-span bridges. The bridge’s peak seismic responses do not vary monotonously with the apparent wave velocity due to the traveling wave resonance. A new traveling wave excitation method that can simplify the multisupport excitation process into a two-support excitation process is developed.

Spectroscopy of high lying resonances in {sup 9}Be produced with radioactive {sup 8}Li beams

Energy Technology Data Exchange (ETDEWEB)

Lepini-Szily, A.; Leistenschneider, E.; Lichtenthäler, R.; Guimaraes, V.; Condori, R. Pampa; Scarduelli, V.; Rossi, E.; Zagatto, V.A.; Aguiar, V.A.P.; Duarte, J., E-mail: alinka@if.usp.br [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Instituto de Fisica; Mendes Junior, D.R.; Faria, P.N. de; Santos, H. [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil). Instituto de Fisica; Descouvemont, P. [Physique Nucleaire Theorique et Physique Mathematique, Universite Libre de Bruxelles (ULB), Brussels (Belgium); Barioni, A. [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil); Pires, K.C.C. [Universidade Tecnologica Federal do Parana (UFTPR), Cornelio Procopio, PR (Brazil); Morcelle, V. [Universidade Federal de Itajuba (UNIFEI), Itabira, MG (Brazil); Moraes, M.C. [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil); Britos, T.; Assuncao, M. [Universidade Federal de Sao Paulo (UNIFESP), Diadema, SP (Brazil); Zamora, J.C. [Technische Universität Darmstadt, (Germany); Shorto, J.M.B. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

2014-07-01

We present the results of the {sup 8}Li(p,α){sup 5}He and {sup 8}Li(p,p){sup 8}Li reactions measured at the RIBRAS (Radioactive Ion Beams in Brazil) system. The experiment was realized in inverse kinematics using a thick [CH{sub 2}]{sub n} polyethylene target and an incident {sup 8}Li beam, produced by RIBRAS. Using the thick target method, the complete excitation function could be measured between E{sub cm} = 0.2 - 2.1 MeV, which includes the Gamow peak energy region. The excitation function of the {sup 8}Li(p,α){sup 5}He reaction, populating resonances between 16.888 and 19.0 MeV in {sup 9}Be, was obtained[1] and the resonances were fitted using R-matrix calculations. This study shed light on spins, parities, partial widths and isospin values of high lying resonances in {sup 9}Be. The measurement of the resonant elastic scattering {sup 8}Li(p,p){sup 8}Li populating resonances in the same energy region can constrain the resonance parameters. Preliminary results of the elastic scattering are also presented. (author)

High-Resolution Spectroscopy of Jet-Cooled 1,1 '-Diphenylethylene: Electronically Excited and Ionic States of a Prototypical Cross-Conjugated System

NARCIS (Netherlands)

Smolarek, S.; Vdovin, A.; Rijs, A.; van Walree, C. A.; Zgierski, M. Z.; Buma, W. J.

2011-01-01

The photophysics of a prototypical cross-conjugated pi-system, 1,1'-diphenylethylene, have been studied using high-resolution resonance enhanced multiphoton ionization excitation spectroscopy and zero kinetic energy photoelectron spectroscopy, in combination with advanced ab initio

Impact-parameter dependence of giant resonance excitations in relativistic heavy-ion collisions

International Nuclear Information System (INIS)

Gruenschloss, A.; Boretzky, K.; Aumann, T.

1999-09-01

Angular distributions of Xe fragments produced in peripheral collisions of a 136 Xe beam (700 MeV/nucleon) with 208 Pb and nat Sn targets were measured. Equivalent sharp-cutoff minimum impact parameters were derived on the basis of a semi-classical description for the electromagnetic excitation of one- and two-phonon giant resonances. The results are compared with current standard parametrizations of minimum impact parameters and with the soft-spheres model using realistic mass density distributions for projectile and targets. (orig.)

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

Giant dipole resonance in hot nuclei

International Nuclear Information System (INIS)

Mau, N.V.

1993-01-01

Giant resonances built on an excited state of the nucleus at a finite temperature T are studied. The following questions are investigated: how long such collective effects occur in a nucleus when T increases. How the properties of the giant resonances vary when the temperature increases. How the study of giant resonances in hot nuclei can give information on the structure of the nucleus in a highly excited state. The special case of the giant dipole resonance is studied. Some of the experimental results are reviewed and in their theoretical interpretation is discussed. (K.A.). 56 refs., 20 figs., 4 tabs

Excitation of the ionospheric Alfvén resonator from the ground: Theory and experiments

Science.gov (United States)

Streltsov, A. V.; Chang, C.-L.; Labenski, J.; Milikh, G.; Vartanyan, A.; Snyder, A. L.

2011-10-01

We report results from numerical and experimental studies of the excitation of ULF shear Alfvén waves inside the ionospheric Alfvén resonator (IAR) by heating the ionosphere with powerful HF waves launched from the High Frequency Active Auroral Research Program (HAARP) facility in Alaska. Numerical simulations of the two-fluid MHD model describing IAR in a dipole magnetic field geometry with plasma parameters taken from the observations at HAARP during the October-November 2010 experimental campaign reveal that the IAR quality is higher during nighttime conditions, when the ionospheric conductivity is very low. Simulations also reveal that the resonance wave cannot be identified from the magnetic measurements on the ground or at an altitude above 600 km because the magnetic field in this wave has nodes on both ends of the resonator, and the best way to detect IAR modes is by measuring the electric field on low Earth orbit satellites. These theoretical predictions are in good, quantitative agreement with results from observations: In particular, (1) observations from the ground-based magnetometer at the HAARP site demonstrate no significant difference in the amplitudes of the magnetic field generated by HAARP in the frequency range from 0 to 5 Hz, and (2) the DEMETER satellite detected the electric field of the IAR first harmonic at an altitude of 670 km above HAARP during the heating experiment.

Resonant excitation of high order modes in the 3.9 GHz cavity of the Linac Coherent Light Source

Science.gov (United States)

Lunin, A.; Khabiboulline, T.; Solyak, N.; Sukhanov, A.; Yakovlev, V.

2018-02-01

Construction of the Linac Coherent Light Source II (LCLS-II) is underway for the world's first hard x-ray free-electron laser. A central part of the LCLS-II project is a 4 GeV superconducting radio frequency electron linac that will operate in the continuous wave (cw) mode. The linac is segmented into four sections named as L 0 , L 1 , L 2 , and L 3 . Two 3.9 GHz cryomodules, each housing of eight third-harmonic cavities similar to the cavities developed for the European X-ray Free Electron Laser (XFEL), will be used in section L 1 of the linac for linearizing the longitudinal beam profile. In this paper, we present a study of trapped high order modes (HOMs) excited by a cw electron beam in the third-harmonic cavities of the LCLS-II linac. A detailed comparison of the original XFEL design and the LCLS-II design with a modified end group is performed in order to estimate the effect of a reduced beam pipe aperture on the efficiency of HOM damping. Furthermore, we apply a statistical analysis of the eigenmode spectrum for the estimation of the probability of resonant HOM losses and influence of HOMs on beam dynamics.

Numerical Simulation of Liquid Sloshing Problem under Resonant Excitation

Directory of Open Access Journals (Sweden)

Fu-kun Gui

2014-04-01

Full Text Available Numerical simulations were conducted to investigate the fluid resonance in partially filled rectangular tank based on the OpenFOAM package of viscous fluid model. The numerical model was validated by the available theoretical, numerical, and experimental data. The study was mainly focused on the large amplitude sloshing motion and the corresponding impact force around the resonant condition. It was found that, for the 2D situation, the double pressure peaks happened near to the side walls around the still water level. And they were corresponding to the local free surface rising up and set-down, respectively. The impulsive loads on the tank corner with extreme magnitudes were observed as the free surface impacted the ceiling. The 3D numerical results showed that the free surface amplitudes along the side walls varied diversely, depending on the direction and frequency of the external excitation. The characteristics of the pressure around the still water level and tank ceiling were also presented. According to the computational results, it was found that the 2D numerical model can predict the impact loads near the still water level as accurately as 3D model. However, the impulsive pressure near the tank ceiling corner was remarkably underestimated.

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)

High energy nuclear excitations

International Nuclear Information System (INIS)

Gogny, D.; Decharge, J.

1983-09-01

The main purpose of this talk is to see whether a simple description of the nuclear excitations permits one to characterize some of the high energy structures recently observed. The discussion is based on the linear response to different external fields calculated using the Random Phase Approximation. For those structure in heavy ion collisions at excitation energies above 50 MeV which cannot be explained with such a simple approach, we discuss a possible mechanism for this heavy ion scattering

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.

Photoresponse of 60Ni below 10-MeV excitation energy: Evolution of dipole resonances in fp-shell nuclei near N=Z

Science.gov (United States)

Scheck, M.; Ponomarev, V. Yu.; Fritzsche, M.; Joubert, J.; Aumann, T.; Beller, J.; Isaak, J.; Kelley, J. H.; Kwan, E.; Pietralla, N.; Raut, R.; Romig, C.; Rusev, G.; Savran, D.; Schorrenberger, L.; Sonnabend, K.; Tonchev, A. P.; Tornow, W.; Weller, H. R.; Zilges, A.; Zweidinger, M.

2013-10-01

Background: Within the last decade, below the giant dipole resonance the existence of a concentration of additional electric dipole strength has been established. This accumulation of low-lying E1 strength is commonly referred to as pygmy dipole resonance (PDR).Purpose: The photoresponse of 60Ni has been investigated experimentally and theoretically to test the evolution of the PDR in a nucleus with only a small neutron excess. Furthermore, the isoscalar and isovector M1 resonances were investigated.Method: Spin-1 states were excited by exploiting the (γ,γ') nuclear resonance fluorescence technique with unpolarized continuous bremsstrahlung as well as with fully linearly polarized, quasimonochromatic, Compton-backscattered laser photons in the entrance channel of the reaction.Results: Up to 10 MeV a detailed picture of J=1 levels was obtained. For the preponderant number of the individual levels spin and parity were firmly assigned. Furthermore, branching ratios, transition widths, and reduced B(E1) or B(M1) excitation probability were calculated from the measured scattering cross sections. A comparison with theoretical results obtained within the quasiparticle phonon model allows an insight into the microscopic structure of the observed states.Conclusions: Below 10 MeV the directly observed E1 strength [∑B(E1)↑=(153.8±9.5) e2(fm)2] exhausts 0.5% of the Thomas-Reiche-Kuhn sum rule. This value increases to 0.8% of the sum rule [∑B(E1)↑=(250.9±31.1) e2(fm)2] when indirectly observed branches to lower-lying levels are considered. Two accumulations of M1 excited spin-1 states near 8 and 9 MeV excitation energy are identified as isoscalar and isovector M1 resonances dominated by proton and neutron f7/2→f5/2 spin-flip excitations. The B(M1)↑ strength of these structures accumulates to 3.94(27)μN2.

Ferromagnetic resonance frequency increase and resonance line broadening of a ferromagnetic Fe–Co–Hf–N film with in-plane uniaxial anisotropy by high-frequency field perturbation

International Nuclear Information System (INIS)

Seemann, K.; Leiste, H.; Krüger, K.

2013-01-01

Soft ferromagnetic Fe-Co-Hf-N films, produced by reactive r.f. magnetron sputtering, are useful to study the ferromagnetic resonance (FMR) by means of frequency domain permeability measurements up to the GHz range. Films with the composition Fe 33 Co 43 Hf 10 N 14 exhibit a saturation polarisation J s of around 1.35 T. They are consequently considered as being uniformly magnetised due to an in-plane uniaxial anisotropy of approximately μ 0 H u ≈4.5 m T after annealing them, e.g., at 400 °C in a static magnetic field for 1 h. Being exposed to a high-frequency field, the precession of magnetic moments leads to a marked frequency-dependent permeability with a sharp Lorentzian shaped imaginary part at around 2.33 GHz (natural resonance peak), which is in a very good agreement with the modified Landau–Lifschitz–Gilbert (LLG) differential equation. A slightly increased FMR frequency and a clear increase in the resonance line broadening due to an increase of the exciting high-frequency power (1–25.1 mW), considered as an additional perturbation of the precessing system of magnetic moments, could be discovered. By solving the homogenous LLG differential equation with respect to the in-plane uniaxial anisotropy, it was revealed that the high-frequency field perturbation impacts the resonance peak position f FMR and resonance line broadening Δf FMR characterised by a completed damping parameter α=α eff +Δα. Adapted from this result, the increase in f FMR and decrease in lifetime of the excited level of magnetic moments associated with Δf FMR , similar to a spin-½ particle in a static magnetic field, was theoretically elaborated as well as compared with experimental data. - Highlights: • Impact on the resonance frequency and resonance line by the high-frequency power. • Theoretic approach by solving the LLG differential equation. • Experimental verification and magnon processes. • Theoretical and experimental determination of the resonance state

Ultra-broadband and high-efficiency polarization conversion metasurface with multiple plasmon resonance modes

International Nuclear Information System (INIS)

Dong Guo-Xiang; Xia Song; Li Wei; Zhang An-Xue; Xu Zhuo; Wei Xiao-Yong; Shi Hong-Yu

2016-01-01

In this paper, we present a novel metasurface design that achieves a high-efficiency ultra-broadband cross polarization conversion. The metasurface is composed of an array of unit resonators, each of which combines an H-shaped structure and two rectangular metallic patches. Different plasmon resonance modes are excited in unit resonators and allow the polarization states to be manipulated. The bandwidth of the cross polarization converter is 82% of the central frequency, covering the range from 15.7 GHz to 37.5 GHz. The conversion efficiency of the innovative new design is higher than 90%. At 14.43 GHz and 40.95 GHz, the linearly polarized incident wave is converted into a circularly polarized wave. (paper)

High-resolution spectroscopy of jet-cooled 1,1 '-diphenylethylene: electronically excited and ionic states of a prototypical cross-conjugated system

NARCIS (Netherlands)

Smolarek, S.; Vdovin, A.; Rijs, A.; van Walree, C.A.; Zgierski, M.Z.; Buma, W.J.

2011-01-01

The photophysics of a prototypical cross-conjugated π-system, 1,1′-diphenylethylene, have been studied using high-resolution resonance enhanced multiphoton ionization excitation spectroscopy and zero kinetic energy photoelectron spectroscopy, in combination with advanced ab initio calculations. We

X-ray excited photoluminescence near the giant resonance in solid-solution Gd(1-x)Tb(x)OCl nanocrystals and their retention upon solvothermal topotactic transformation to Gd(1-x)Tb(x)F3.

Science.gov (United States)

Waetzig, Gregory R; Horrocks, Gregory A; Jude, Joshua W; Zuin, Lucia; Banerjee, Sarbajit

2016-01-14

Design rules for X-ray phosphors are much less established as compared to their optically stimulated counterparts owing to the absence of a detailed understanding of sensitization mechanisms, activation pathways and recombination channels upon high-energy excitation. Here, we demonstrate a pronounced modulation of the X-ray excited photoluminescence of Tb(3+) centers upon excitation in proximity to the giant resonance of the host Gd(3+) ions in solid-solution Gd1-xTbxOCl nanocrystals prepared by a non-hydrolytic cross-coupling method. The strong suppression of X-ray excited optical luminescence at the giant resonance suggests a change in mechanism from multiple exciton generation to single thermal exciton formation and Auger decay processes. The solid-solution Gd1-xTbxOCl nanocrystals are further topotactically transformed with retention of a nine-coordinated cation environment to solid-solution Gd1-xTbxF3 nanocrystals upon solvothermal treatment with XeF2. The metastable hexagonal phase of GdF3 can be stabilized at room temperature through this topotactic approach and is transformed subsequently to the orthorhombic phase. The fluoride nanocrystals indicate an analogous but blue-shifted modulation of the X-ray excited optical luminescence of the Tb(3+) centers upon X-ray excitation near the giant resonance of the host Gd(3+) ions.

Study of high-spin analog resonances near the N=50 neutron shell

International Nuclear Information System (INIS)

Gales, S.; El Hage, Y.; Schapira, J.P.; Fortier, S.; Laurent, H.; Maison, J.M.

1979-01-01

The 96 Zr( 3 He,d) 97 Nb and the 92 Mo( 3 He,d) 93 Tc reactions, investigated at, respectively 39.0 and 28.5 MeV incident energies, were used to selectively populate high-spin analog resonances in the 97 Nb and 93 Tc nuclei. Angular distributions were measured for the dsub(3/2), gsub(7/2) and hsub(11/2) analog states of the low-lying levels in 97 Zr. A DWBA analysis of the data for these unbound levels (using Gamov functions as form factors) was carried out and spectroscopic strengths extracted. The 96 Zr( 3 He,dp) and 92 Mo( 3 He,dp) reactions were performed, respectively, at 37.5 and 30 MeV incident energies. The angular distributions of the emitted protons were measured in coincidence using method II of Litherland and Ferguson with 0 0 detection of deuteron groups. Spins, population parameters and proton branching ratios to the ground state and excited states of the targets were determined from the analysis of the angular correlation data. The position of the neutron threshold as compared with the excitation energies of the analog states in 97 Nb and 93 Tc is found to be an important parameter in the extraction of the structure informations on core-excited components in the parent levels wave functions. Neutron particle-hole multiplets are observed for the first time in 96 Zr through the decay of the gsub(7 /2) and hsub(11/2) analog resonances. The limitation of the present method due to the neutron threshold or to the energy resolution in the proton channel is discussed and compared with the results of inelastic resonant scattering through isobaric analog resonances

Photoabsorption and S 2p photoionization of the SF6 molecule: resonances in the excitation energy range of 200-280 eV.

Science.gov (United States)

Stener, M; Bolognesi, P; Coreno, M; O'Keeffe, P; Feyer, V; Fronzoni, G; Decleva, P; Avaldi, L; Kivimäki, A

2011-05-07

Photoabsorption and S 2p photoionization of the SF(6) molecule have been studied experimentally and theoretically in the excitation energy range up to 100 eV above the S 2p ionization potentials. In addition to the well-known 2t(2g) and 4e(g) shape resonances, the spin-orbit-resolved S 2p photoionization cross sections display two weak resonances between 200 and 210 eV, a wide resonance around 217 eV, a Fano-type resonance around 240 eV, and a second wide resonance around 260 eV. Calculations based on time-dependent density functional theory allow us to assign the 217-eV and 260-eV features to the shape resonances in S 2p photoionization. The Fano resonance is caused by the interference between the direct S 2p photoionization channel and the resonant channel that results from the participator decay of the S 2s(-1)6t(1u) excited state. The weak resonances below 210-eV photon energy, not predicted by theory, are tentatively suggested to originate from the coupling between S 2p shake-up photoionization and S 2p single-hole photoionization. The experimental and calculated angular anisotropy parameters for S 2p photoionization are in good agreement.

Dielectronic recombination and resonant transfer excitation processes for helium-like krypton

Institute of Scientific and Technical Information of China (English)

Hu Xiao-Li; Qu Yi-Zhi; Zhang Song-Bin; Zhang Yu

2012-01-01

The relativistic configuration interaction method is employed to calculate the dielectronic recombination (DR) cross sections of helium-like krypton via the 1s21nl' (n =2,3,...,15) resonances.Then,the resonant transfer excitation (RTE) processes of Kr34+ colliding with H,He,H2,and CHx (x =0-4) targets are investigated under the impulse approximation.The needed Compton profiles of targets are obtained from the Hartree-Fock wave functions.The RTE cross sections are strongly dependent on DR resonant energies and strengths,and the electron momentum distributions of the target.For H2 and H targets,the ratio of their RTE cross sections changes from 1.85 for the 1s2121' to 1.88 for other resonances,which demonstrates the weak molecular effects on the Compton profiles of H2.For CHx (x =0-4) targets,the main contribution to the RTE cross section comes from the carbon atom since carbon carries 6 electrons;as the number of hydrogen increases in CHx,the RTE cross section almost increases by the same value,displaying the strong separate atom character for the hydrogen.However,further comparison of the individual orbital contributions of C(2p,2s,ls) and CH4(1t2,2a1,1a1) to the RTE cross sections shows that the molecular effects induce differences of about 25.1％,19.9％,and 0.2％ between 2p-1t2,2s-2a1,and 1s-1a1 orbitals,respectively.

Pure-Phase Selective Excitation in Fast-Relaxing Systems

Science.gov (United States)

Zangger, Klaus; Oberer, Monika; Sterk, Heinz

2001-09-01

Selective pulses have been used frequently for small molecules. However, their application to proteins and other macromolecules has been limited. The long duration of shaped-selective pulses and the short T2 relaxation times in proteins often prohibited the use of highly selective pulses especially on larger biomolecules. A very selective excitation can be obtained within a short time by using the selective excitation sequence presented in this paper. Instead of using a shaped low-intensity radiofrequency pulse, a cluster of hard 90° pulses, delays of free precession, and pulsed field gradients can be used to selectively excite a narrow chemical shift range within a relatively short time. Thereby, off-resonance magnetization, which is allowed to evolve freely during the free precession intervals, is destroyed by the gradient pulses. Off-resonance excitation artifacts can be removed by random variation of the interpulse delays. This leads to an excitation profile with selectivity as well as phase and relaxation behavior superior to that of commonly used shaped-selective pulses. Since the evolution of scalar coupling is inherently suppressed during the double-selective excitation of two different scalar-coupled nuclei, the presented pulse cluster is especially suited for simultaneous highly selective excitation of N-H and C-H fragments. Experimental examples are demonstrated on hen egg white lysozyme (14 kD) and the bacterial antidote ParD (19 kD).

Nuclear spin and isospin excitations

International Nuclear Information System (INIS)

Osterfeld, F.

1992-01-01

A review is given of our present knowledge of collective spin-isospin excitations in nuclei. Most of this knowledge comes from intermediate-energy charge-exchange reactions and from inelastic electron- and proton-scattering experiments. The nuclear-spin dynamics is governed by the spin-isospin-dependent two-nucleon interaction in the medium. This interaction gives rise to collective spin modes such as the giant Gamow-Teller resonances. An interesting phenomenon is that the measured total Gamow-Teller transition strength in the resonance region is much less than a model-independent sum rule predicts. Two physically different mechanisms have been discussed to explain this so-called quenching of the total Gamow-Teller strength: coupling to subnuclear degrees of freedom in the form of Δ-isobar excitation and ordinary nuclear configuration mixing. Both detailed nuclear structure calculations and extensive analyses of the scattering data suggest that the nuclear configuration mixing effect is the more important quenching mechanism, although subnuclear degrees of freedom cannot be ruled out. The quenching phenomenon occurs for nuclear-spin excitations at low excitation energies (ω∼10--20 MeV) and small-momentum transfers (q≤0.5 fm -1 ). A completely opposite effect is anticipated in the high (ω,q)-transfer region (0≤ω≤500 MeV, 0.5≤q≤3 fm -1 ). The nuclear spin-isospin response might be enhanced due to the attractive pion field inside the nucleus. Charge-exchange reactions at GeV incident energies have been used to study the quasifree peak region and the Δ-resonance region. An interesting result of these experiments is that the Δ excitation in the nucleus is shifted downwards in energy relative to the Δ excitation of the free proton

Electron collisions and internal excitation in stored molecular ion beams

International Nuclear Information System (INIS)

Buhr, H.

2006-01-01

In storage ring experiments the role, which the initial internal excitation of a molecular ion can play in electron collisions, and the effect of these collisions on the internal excitation are investigated. Dissociative recombination (DR) and inelastic and super-elastic collisions are studied in the system of He + 2 . The DR rate coefficient at low energies depends strongly on the initial vibrational excitation in this system. Therefore changes in the DR rate coefficient are a very sensitive probe for changes in the vibrational excitation in He + 2 , which is used to investigate the effects of collisions with electrons and residual gas species. The low-energy DR of HD + is rich with resonances from the indirect DR process, when certain initial rotational levels in the molecular ion are coupled to levels in neutral Rydberg states lying below the ion state. Using new procedures for high-resolution electron-ion collision spectroscopy developed here, these resonances in the DR cross section can be measured with high energy sensitivity. This allows a detailed comparison with results of a MQDT calculation in an effort to assign some or all of the resonances to certain intermediate Rydberg levels. (orig.)

Electron collisions and internal excitation in stored molecular ion beams

Energy Technology Data Exchange (ETDEWEB)

Buhr, H.

2006-07-26

In storage ring experiments the role, which the initial internal excitation of a molecular ion can play in electron collisions, and the effect of these collisions on the internal excitation are investigated. Dissociative recombination (DR) and inelastic and super-elastic collisions are studied in the system of He{sup +}{sub 2}. The DR rate coefficient at low energies depends strongly on the initial vibrational excitation in this system. Therefore changes in the DR rate coefficient are a very sensitive probe for changes in the vibrational excitation in He{sup +}{sub 2}, which is used to investigate the effects of collisions with electrons and residual gas species. The low-energy DR of HD{sup +} is rich with resonances from the indirect DR process, when certain initial rotational levels in the molecular ion are coupled to levels in neutral Rydberg states lying below the ion state. Using new procedures for high-resolution electron-ion collision spectroscopy developed here, these resonances in the DR cross section can be measured with high energy sensitivity. This allows a detailed comparison with results of a MQDT calculation in an effort to assign some or all of the resonances to certain intermediate Rydberg levels. (orig.)

Accurate Cross Sections for Excitation of Resonance Transitions in Atomic Oxygen

Science.gov (United States)

Tayal, S. S.

2004-01-01

Electron collision excitation cross sections for the resonance 2p(sup)4 (sup 3)P-2p(sup 3)3s (sup 3)S(sup 0), 2p(sup 4) (sup 3)P-2p(sup 3)3d (sup 3)D(sup 0), 2p4 (sup 3)P-2p(sup 3)3s (sup 3)D(sup 0), 2p(sup 4) (sup 3)P-2p(sup 3)3s (sup 3)P(sup 0) and 2p(sup 4) (sup 3)P-2s2p(sup 5) (sup 3)P(sup 0) transitions have been calculated by using the R matrix with a pseudostates approach for incident electron energies from near threshold to 100 eV. The excitation of these transition sgives rise to strong atomic oxygen emission features at 1304, 1027, 989, 878, and 792 Angstrom in the spectra of several planetary atmospheres. We included 22 spectroscopic bound and autoionizing states and 30 pseudostates in the close-coupling expansion. The target wave functions are chosen to properly account for the important correlation and relaxation effects. The effect of coupling to the continuum is included through the use of pseudostates. The contribution of the ionization continuum is significant for resonance transitions. Measured absolute direct excitation cross sections of 0 I are reported by experimental groups from the Jet Propulsion Laboratory and Johns Hopkins University. Good agreement is noted for the 2p(sup)4 (sup 3)P-2p(sup 3)3s (sup 3)S(sup 0) transition (lambda 1304 Ang) with measured cross sections from both groups that agree well with each other. There is disagreement between experiments for other transitions. Our results support the measured cross sections from the Johns Hopkins University for the 2p(sup 4) (sup 3)P-2p(sup 3)3d (sup 3)D(sup 0) and 2p4 (sup 3)P-2p(sup 3)3s (sup 3)D(sup 0) transitions, while for the 2p4 (sup 3)P-2p(sup 3)3s (sup 3)D(sup 0) transition the agreement is switched to the measured cross sections from the Jet Propulsion Laboratory.

High power laser exciter accelerators

International Nuclear Information System (INIS)

Martin, T.H.

1975-01-01

Recent developments in untriggered oil and water switching now permit the construction of compact, high energy density pulsed power sources for laser excitation. These accelerators, developed principally for electron beam fusion studies, appear adaptable to laser excitation and will provide electron beams of 10 13 to 10 14 W in the next several years. The accelerators proposed for e-beam fusion essentially concentrate the available power from the outside edge of a disk into the central region where the electron beam is formed. One of the main problem areas, that of power flow at the vacuum diode insulator, is greatly alleviated by the multiplicity of electron beams that are allowable for laser excitation. A proposal is made whereby the disk-shaped pulsed power sections are stacked vertically to form a series of radially flowing electron beams to excite the laser gas volume. (auth)

Interaction between doubly-excited 4p4nln'l' resonances in KrI

International Nuclear Information System (INIS)

Sukhorukov, V L; Petrov, I D; Demekhin, Ph V; Schmoranzer, H; Mickat, S; Kammer, S; Schartner, K-H; Klumpp, S; Werner, L; Ehresmann, A

2007-01-01

Photoionization cross sections for the 4p 4 ( 3 P)5s 4 P 5/2,3/2,1/2 satellites and 4s → εl, 4p → εl main lines of Kr II were measured using the photon-induced fluorescence spectroscopy in the exciting-photon energy range between 27.80 eV and 29.44 eV with extremely narrow bandwidth (1.7 meV at 28.55 eV) of the monochromatized synchrotron radiation. The observed resonances were assigned to the 4p 4 5s( 4 P 1/2 )np and 4p 4 5s( 2 P 3/2 )np Rydberg series on the basis of the calculations including core relaxation and interaction between many resonances and many continua. The calculation shows that the resonance structure in the photoionization channels exists due to the 4p 4 ( 1 D)5s 2 D 5/2 6p 3/2 and 4p 4 ( 1 D)5s 2 D 3/2 6p 3/2,1/2 promoter states which strongly perturb the above Rydberg series

Multispectral code excited linear prediction coding and its application in magnetic resonance images.

Science.gov (United States)

Hu, J H; Wang, Y; Cahill, P T

1997-01-01

This paper reports a multispectral code excited linear prediction (MCELP) method for the compression of multispectral images. Different linear prediction models and adaptation schemes have been compared. The method that uses a forward adaptive autoregressive (AR) model has been proven to achieve a good compromise between performance, complexity, and robustness. This approach is referred to as the MFCELP method. Given a set of multispectral images, the linear predictive coefficients are updated over nonoverlapping three-dimensional (3-D) macroblocks. Each macroblock is further divided into several 3-D micro-blocks, and the best excitation signal for each microblock is determined through an analysis-by-synthesis procedure. The MFCELP method has been applied to multispectral magnetic resonance (MR) images. To satisfy the high quality requirement for medical images, the error between the original image set and the synthesized one is further specified using a vector quantizer. This method has been applied to images from 26 clinical MR neuro studies (20 slices/study, three spectral bands/slice, 256x256 pixels/band, 12 b/pixel). The MFCELP method provides a significant visual improvement over the discrete cosine transform (DCT) based Joint Photographers Expert Group (JPEG) method, the wavelet transform based embedded zero-tree wavelet (EZW) coding method, and the vector tree (VT) coding method, as well as the multispectral segmented autoregressive moving average (MSARMA) method we developed previously.

Structural dynamics of phenylisothiocyanate in the light-absorbing excited states: Resonance Raman and complete active space self-consistent field calculation study

International Nuclear Information System (INIS)

Ouyang, Bing; Xue, Jia-Dan; Zheng, Xuming; Fang, Wei-Hai

2014-01-01

The excited state structural dynamics of phenyl isothiocyanate (PITC) after excitation to the light absorbing S 2 (A′), S 6 (A′), and S 7 (A′) excited states were studied by using the resonance Raman spectroscopy and complete active space self-consistent field method calculations. The UV absorption bands of PITC were assigned. The vibrational assignments were done on the basis of the Fourier transform (FT)-Raman and FT-infrared measurements, the density-functional theory computations, and the normal mode analysis. The A-, B-, and C-bands resonance Raman spectra in cyclohexane, acetonitrile, and methanol solvents were, respectively, obtained at 299.1, 282.4, 266.0, 252.7, 228.7, 217.8, and 208.8 nm excitation wavelengths to probe the corresponding structural dynamics of PITC. The results indicated that the structural dynamics in the S 2 (A′), S 6 (A′), and S 7 (A′) excited states were very different. The conical intersection point CI(S 2 /S 1 ) were predicted to play important role in the low-lying excited state decay dynamics. Two major decay channels were predicted for PITC upon excitation to the S 2 (A′) state: the radiative S 2,min → S 0 transition and the nonradiative S 2 → S 1 internal conversion via CI(S 2 /S 1 ). The differences in the decay dynamics between methyl isothiocyanate and PITC in the first light absorbing excited state were discussed. The role of the intersystem crossing point ISC(S 1 /T 1 ) in the excited state decay dynamics of PITC is evaluated

Resonant excitation of high order modes in the 3.9 GHz cavity of the Linac Coherent Light Source

Directory of Open Access Journals (Sweden)

A. Lunin

2018-02-01

Full Text Available Construction of the Linac Coherent Light Source II (LCLS-II is underway for the world’s first hard x-ray free-electron laser. A central part of the LCLS-II project is a 4 GeV superconducting radio frequency electron linac that will operate in the continuous wave (cw mode. The linac is segmented into four sections named as L0, L1, L2, and L3. Two 3.9 GHz cryomodules, each housing of eight third-harmonic cavities similar to the cavities developed for the European X-ray Free Electron Laser (XFEL, will be used in section L1 of the linac for linearizing the longitudinal beam profile. In this paper, we present a study of trapped high order modes (HOMs excited by a cw electron beam in the third-harmonic cavities of the LCLS-II linac. A detailed comparison of the original XFEL design and the LCLS-II design with a modified end group is performed in order to estimate the effect of a reduced beam pipe aperture on the efficiency of HOM damping. Furthermore, we apply a statistical analysis of the eigenmode spectrum for the estimation of the probability of resonant HOM losses and influence of HOMs on beam dynamics.

Peripheral collisions of heavy ions induced by 40Ar at intermediate energies: giant resonance high energy structures and projectile fragmentation

International Nuclear Information System (INIS)

Blumenfeld, Y.

1987-09-01

The results obtained in similar studies at low incident energies are first of all reviewed. The time of flight spectrometer built for the experiments is then described. A study of the properties of the projectile-like fragments shows numerous deviations from the relativistic energy fragmentation model. Evidence for a strong surface transfer reaction component is given and the persistence of mean field effects at intermediate energies is stressed. A calculation of the contribution of the transfer evaporation mechanism to the inelastic spectra shows that this mechanism is responible for the major part of the background measured at high excitation energy and can in some cases induce narrow structures in the spectra. The inelastic spectra shows a strong excitation of the giant quadrupole resonance. In the region between 20 and 80 MeV excitation energy narrow structures are present for all the studied systems. Statistical and Fourier analysises allow to quantify the probabilities of existence, the widths and the excitation energies of these structures. A transfer evaporation hypothesis cannot consistently reproduce all the observed structures. The excitation energies of the structures can be well described by phenomenological laws where the energies are proportional to the -1/3 power of the target mass. Complete calculations of the excitation probabilities of giant resonances and multiphonon states are performed within a model where the nuclear excitation are calculated microscopically in the Random Phase Approximation. It is shown that a possible interpretation of the structures is the excitation of multiphonon states built with 2 + giant resonances [fr

Nonlinear optical sub-bandgap excitation of ZnO-based photonic resonators

Energy Technology Data Exchange (ETDEWEB)

Bader, Christina A.; Zeuner, Franziska; Bader, Manuel H. W.; Zentgraf, Thomas; Meier, Cedrik [Department of Physics and Center for Optoelectronics and Photonics Paderborn (CeOPP), Universität Paderborn, Warburger Str. 100, 33098 Paderborn (Germany)

2015-12-07

Zinc oxide (ZnO) is a versatile candidate for photonic devices due to its highly efficient optical emission. However, for pumping of ZnO photonic devices UV-sources are required. Here, we investigate the alternative usage of widely available pulsed near-infrared (NIR)-sources and compare the efficiency of linear and nonlinear excitation processes. We found that bulk ZnO, ZnO thin films grown by molecular beam epitaxy, and ZnO/SiO{sub 2} microdisk devices exhibit strong nonlinear response when excited with NIR pulses (λ ≈ 1060 nm). In addition, we show that the ZnO/SiO{sub 2} microdisks exhibit sharp whispering gallery modes over the blue-yellow part of the visible spectrum for both excitation conditions and high Q-factors up to Q = 4700. The results demonstrate that nonlinear excitation is an efficient way to pump ZnO photonic devices.

Electron dynamics in the core-excited CS 2 molecule revealed through resonant inelastic x-ray scattering spectroscopy

OpenAIRE

Marchenko , T; Carniato , S; Journel , L; Guillemin , R; Kawerk , E; Žitnik , M; Kavčič , M; Bučar , K; Bohinc , R; Petric , M; da Cruz , V Vaz; Gel'mukhanov , F; Simon , Marielle

2015-01-01

International audience; We present an experimental and theoretical study of resonant inelastic x-ray scattering (RIXS) in the CS2 molecule near the S 1s edge. We show that localization of the S 1s core-hole occurs in CS2 during the RIXS process due to the orientational dephasing of interference between the waves scattering on the two sulfur atoms. Strong evolution of the RIXS profile with the excitation energy far below the first absorption resonance reflects the onset of electron dynamics tr...

Probing single magnon excitations in Sr₂IrO₄ using O K-edge resonant inelastic x-ray scattering.

Science.gov (United States)

Liu, X; Dean, M P M; Liu, J; Chiuzbăian, S G; Jaouen, N; Nicolaou, A; Yin, W G; Rayan Serrao, C; Ramesh, R; Ding, H; Hill, J P

2015-05-27

Resonant inelastic x-ray scattering (RIXS) at the L-edge of transition metal elements is now commonly used to probe single magnon excitations. Here we show that single magnon excitations can also be measured with RIXS at the K-edge of the surrounding ligand atoms when the center heavy metal elements have strong spin-orbit coupling. This is demonstrated with oxygen K-edge RIXS experiments on the perovskite Sr2IrO4, where low energy peaks from single magnon excitations were observed. This new application of RIXS has excellent potential to be applied to a wide range of magnetic systems based on heavy elements, for which the L-edge RIXS energy resolution in the hard x-ray region is usually poor.

A study on the complexity of a business cycle model with great excitements in non-resonant condition

International Nuclear Information System (INIS)

Ma Junhai; Cui Yaqiang; Liulixia

2009-01-01

Based on the researches of Szydlowski and Krawiec, we studied the inherent complexity of a chaotic business cycle with great excitements in non-resonant condition. First, we got the first-order and second-order approximate solutions of the system by using multiple scale method. Then deduced the formulation reflecting the complex relations between vibration, phase, bifurcation parameter μ and excite frequency Ω of first-order solution. As the great excitement F varied, the global changes of the system solutions were analyzed. We also explored the different paths leading the systems with different parameter combinations into catastrophe region, fuzzy region or chaos region. Finally, we discussed the evolution trends of business cycle models under the above-mentioned conditions. Hence, this paper has some theoretical and practical significance.

Excitation of terahertz modes localized on a layered superconductor: Anomalous dispersion and resonant transmission

Science.gov (United States)

Apostolov, S. S.; Makarov, N. M.; Yampol'skii, V. A.

2018-01-01

We study theoretically the optic transmission through a slab of layered superconductor separated from two dielectric leads by spatial gaps. Based on the transfer matrix formalism along with the Josephson plasma electrodynamic approach, we derive analytic expressions for the transmittance and identify the conditions for the perfect transmission. The special interest of the study is focused on the resonant transmission, which occurs when the wave does not propagate in the spatial gaps. Far from the resonance, the transmittance is exponentially small due to the total internal reflection from the lead-gap interface. However, the excitation of electromagnetic modes localized on the layered superconductor gives rise to a remarkable resonant enhancement of the transmission. Moreover, this phenomenon is significantly modified for the layered superconductors in comparison with usual dielectrics or conductors. The dispersion curves for the modes localized on the layered superconductor are proved to be nonmonotonic, thus resulting in the specific dependence of the transmittance T on the incidence angle θ . In particular, we predict the onset of two resonant peaks in the T (θ ) dependence and their subsequent merge into the broadened single peak with increasing of the wave frequency. Our analytical results are demonstrated by numerical data.

Multi frequency excited MEMS cantilever beam resonator for Mixer-Filter applications

KAUST Repository

Chandran, Akhil A.; Younis, Mohammad I.

2016-01-01

Wireless communication uses Radio Frequency waves to transfer information from one point to another. The modern RF front end devices are implementing MEMS in their designs so as to exploit the inherent properties of MEMS devices, such as its low mass, low power consumption, and small size. Among the components in the RF transceivers, band pass filters and mixers play a vital role in achieving the optimum RF performance. And this paper aims at utilizing an electrostatically actuated micro cantilever beam resonator's nonlinear frequency mixing property to realize a Mixer-Filter configuration through multi-frequency excitation. The paper studies about the statics and dynamics of the device. Simulations are carried out to study the added benefits of multi frequency excitation. The modelling of the cantilever beam has been done using a Reduced Order Model of the Euler-Bernoulli's beam equation by implementing the Galerkin discretization. The device is shown to be able to down-convert signals from 960 MHz of frequency to an intermediate frequency around 50 MHz and 70 MHz in Phase 1 and 2, respectively. The simulation showed promising results to take the project to the next level. © 2016 IEEE.

High energy excitations in itinerant ferromagnets

International Nuclear Information System (INIS)

Prange, R.E.

1984-01-01

Itinerant magnets, those whose electrons move throughout the crystal, are described by band theory. Single particle excitations offer confirmation of band theory, but their description requires important corrections. The energetics of magnetism in iron and nickel is also described in band theory but requires complex bands. Magnetism above the critical temperature and the location of the critical temperature offer discriminants between the two major models of magnetism at high temperature and can be addressed by high energy excitations

Dynamics of Microbeams under Multi-Frequency Excitations

KAUST Repository

Ibrahim, Alwathiqbellah

2017-01-24

This paper presents an investigation of the dynamics of microbeams under multiple harmonic electrostatic excitation frequencies. First, the response of a cantilever microbeam to two alternating current (AC) source excitation is examined. We show by simulations the response of the microbeam at primary resonance (near the fundamental natural frequency) and at secondary resonances (near half, superharmonic, and twice, subharmonic, the fundamental natural frequency). A multimode Galerkin method combined with the Euler-Bernoulli beam equation, accounting for the nonlinear electrostatic force, has been used to develop a reduced order model. The response of the cantilever microbeam to three AC source excitation is also investigated and shown as a promising technique to enhance the bandwidth of resonators. Finally, an experimental study of a clamped-clamped microbeam is conducted, demonstrating the multi-frequency excitation resonances using two, three, and four AC sources.

Dynamics of Microbeams under Multi-Frequency Excitations

KAUST Repository

Ibrahim, Alwathiqbellah; Jaber, Nizar; Chandran, Akhil; Thirupathi, Maloth; Younis, Mohammad I.

2017-01-01

This paper presents an investigation of the dynamics of microbeams under multiple harmonic electrostatic excitation frequencies. First, the response of a cantilever microbeam to two alternating current (AC) source excitation is examined. We show by simulations the response of the microbeam at primary resonance (near the fundamental natural frequency) and at secondary resonances (near half, superharmonic, and twice, subharmonic, the fundamental natural frequency). A multimode Galerkin method combined with the Euler-Bernoulli beam equation, accounting for the nonlinear electrostatic force, has been used to develop a reduced order model. The response of the cantilever microbeam to three AC source excitation is also investigated and shown as a promising technique to enhance the bandwidth of resonators. Finally, an experimental study of a clamped-clamped microbeam is conducted, demonstrating the multi-frequency excitation resonances using two, three, and four AC sources.

Extracting the cross section angular distributions for 15C high-energy resonance excited via the (18O,16O two-neutron transfer reaction

Directory of Open Access Journals (Sweden)

Carbone D.

2016-01-01

Full Text Available The 13C(18O,16O15C reaction has been studied at 84 MeV incident energy. The ejectiles have been momentum analized by the MAGNEX spectrometer and 15C excitation energy spectra have been obtained up to about 20 MeV. In the region above the two-neutron separation energy, a bump has been observed at 13.7 MeV. The extracted cross section angular distribution for this structure, obtained by using different models for background, displays a clear oscillating pattern, typical of resonant state of the residual nucleus.

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.)

Pairing and deformation effects in nuclear excitation spectra

Energy Technology Data Exchange (ETDEWEB)

Repko, A. [Slovak Academy of Sciences, Institute of Physics, Bratislava (Slovakia); Kvasil, J. [Charles University, Institute of Particle and Nuclear Physics, Prague (Czech Republic); Nesterenko, V.O. [Joint Institute for Nuclear Research, Laboratory of Theoretical Physics, Dubna (Russian Federation); State University ' ' Dubna' ' , Dubna (Russian Federation); Reinhard, P.G. [Universitaet Erlangen, Institut fuer Theoretische Physik II, Erlangen (Germany)

2017-11-15

We investigate effects of pairing and of quadrupole deformation on two sorts of nuclear excitations, γ-vibrational K{sup π} = 2{sup +} states and dipole resonances (isovector dipole, pygmy, compression, toroidal). The analysis is performed within the quasiparticle random phase approximation (QRPA) based on the Skyrme energy functional using the Skyrme parametrization SLy6. Particular attention is paid to i) the role of the particle-particle (pp) channel in the residual interaction of QRPA, ii) comparison of volume pairing (VP) and surface pairing (SP), iii) peculiarities of deformation splitting in the various resonances. We find that the impact of the pp-channel on the considered excitations is negligible. This conclusion applies also to any other excitation except for the K{sup π} = 0{sup +} states. Furthermore, the difference between VP and SP is found small (with exception of peak height in the toroidal mode). In the low-energy isovector dipole (pygmy) and isoscalar toroidal modes, the branch K{sup π} = 1{sup -} is shown to dominate over the K{sup π} = 0{sup -} one in the range of excitation energy E < 8-10 MeV. The effect becomes impressive for the toroidal resonance whose low-energy part is concentrated in a high peak of almost pure K{sup π} = 1{sup -} nature. This peculiarity may be used as a fingerprint of the toroidal mode in future experiments. The interplay between pygmy, toroidal and compression resonances is discussed, the interpretation of the observed isoscalar giant dipole resonance is partly revised. (orig.)

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)

Laser-excited Fluorescence And Electron-spin Resonance Of Er3+ In Polycrystalline Alcl3

OpenAIRE

Ceotto G.; Pires M.A.; Sanjurjo J.A.; Rettori C.; Barberis G.E.

1990-01-01

The green fluorescence transitions among the levels corresponding to the 4S3/2 and 4I15/2 configurations of Er3+ diluted in AlCl3 have been measured using laser excitation. The data allow us to determine the crystalline-field splittings of these levels and, in turn, the spin-Hamiltonian parameters. The electron-paramagnetic-resonance spectrum observed at low temperatures is in good agreement with that expected from these parameters. © 1990 The American Physical Society.

Measurement of the Auger decay after resonance excitation of Xe 4d and Kr 3d resonance lines

International Nuclear Information System (INIS)

Eberhardt, W.; Kalkoffen, G.; Kunz, C.

1978-03-01

The Nsub(4,5) 0sub(2,3) 0sub(2,3) Auger spectra from Xe and the Msub(4,5) Nsub(2,3) Nsub(2,3) Auger spectra from Kr are investigated for different photon energies around threshold of ionization. When exciting at the resonance line (4d 9 5s 2 5p 6 6p for Xe and 3d 9 4s 2 4p 6 5p for Kr) we observe the usual Auger multiplet structure to be shifted to higher kinetic energies. Additionally, new lines appear which can be assigned to shake-up processes int he Xe + and Kr + ions. (orig.) [de

Electromagnetic excitation of 136Xe in relativistic heavy ion collisions

International Nuclear Information System (INIS)

Schmidt, R.D.

1991-11-01

In the framework of the experimental program at the accelerator facilities SIS/ESR at the Society for Heavy Ion Research in Darmstadt a detector system for relativistic neutrons was developed, constructed, and applied in first experiments. An essential research aim is the study of collective states after electromagnetic excitation in relativistic heavy ion collisions. In peripheral collisions high-energy virtual photons are exchanged. This leads to the excitation of giant resonances, especially of the giant dipole and quadrupole resonance. An essential decay channel of giant resonances in heavy nuclei is the emission of neutrons, followed by the emission of γ radiation below the particle threshold. These decay channels were studied with the detector system developed by the LAND collaboration. A first experiment on the electromagnetic excitation was performed with a 136 Xe beam at an energy of 700 MeV/u and Pb respectively C targets. (orig./HSI) [de

Radiative capture studies of the electromagnetic decays of highly excited states

Energy Technology Data Exchange (ETDEWEB)

Snover, K. A. [Washington Univ., Seattle (USA). Dept. of Physics; Ikegami, H.; Muraoka, M. [eds.; Osaka Univ., Suita (Japan). Research Center for Nuclear Physics

1980-01-01

Selected examples of interesting E1, M1 and E2 resonance studies in (p, ..gamma..) and (..cap alpha.., ..gamma..) reactions are discussed. These include a unique determination of E1 amplitudes in the /sup 12/C(p,..gamma..sub(o))/sup 13/N reaction, E2 strength in light nuclei, M1 decays to the ground states and to the excited O/sup +/ states of the doubly magic /sup 16/O and /sup 40/Ca nuclei, ''second harmonic'' E1 resonances in (p, ..gamma..), and M1 ..gamma..-decay of stretched particle-hole states in /sup 16/O and /sup 28/Si.

Quantum mechanical resonances

International Nuclear Information System (INIS)

Cisneros S, A.; McIntosh, H.V.

1982-01-01

A discussion of the nature of quantum mechanical resonances is presented from the point of view of the spectral theory of operators. In the case of Bohr-Feshbach resonances, graphs are presented to illustrate the theory showing the decay of a doubly excited metastable state and the excitation of the resonance by an incident particle with proper energy. A characterization of resonances is given as well as a procedure to determine widths using the spectral density function. A sufficient condition is given for the validity of the Breit-Wigner formula for Bohr-Feshbach resonances. (author)

Confocal microscopy and spectroscopy of nanocrystals on a high-Q microsphere resonator

International Nuclear Information System (INIS)

Goetzinger, S; Menezes, L de S; Benson, O; Talapin, D V; Gaponik, N; Weller, H; Rogach, A L; Sandoghdar, V

2004-01-01

We report on experiments where we used a home-made confocal microscope to excite single nanocrystals on a high-Q microsphere resonator. In that way spectra of an individual quantum emitter could be recorded. The Q factor of the microspheres coated with nanocrystals was still up to 10 9 . We also demonstrate the use of a prism coupler as a well-defined output port to collect the fluorescence of an ensemble of nanocrystals coupled to whispering-gallery modes

QPM Analysis of 205Tl Nuclear Excitations below the Giant Dipole Resonance

Directory of Open Access Journals (Sweden)

Benouaret N.

2015-01-01

Full Text Available We analysed our experimental recent findings of the dipole response of the odd-mass stable nucleus 205Tl within the quasi-particle phonon model. Using the phonon basis constructed for the neighbouring 204Hg and wave function configurations for 205Tl consisting of a mixture of quasiparticle ⊗ N-phonon configurations (N=0,1,2, only one group of fragmented dipole excited states has been reproduced at 5.5 MeV in comparison to the experimental distribution which shows a second group at about 5 MeV. The computed dipole transition strengths are mainly of E1 character which could be associated to the pygmy dipole resonance.

QPM Analysis of 205Tl Nuclear Excitations below the Giant Dipole Resonance

Science.gov (United States)

Benouaret, N.; Beller, J.; Isaak, J.; Kelley, J. H.; Pai, H.; Pietralla, N.; Ponomarev, V. Yu.; Raut, R.; Romig, C.; Rusev, G.; Savran, D.; Scheck, M.; Schnorrenberger, L.; Sonnabend, K.; Tonchev, A. P.; Tornow, W.; Weller, H. R.; Zweidinger, M.

2015-05-01

We analysed our experimental recent findings of the dipole response of the odd-mass stable nucleus 205Tl within the quasi-particle phonon model. Using the phonon basis constructed for the neighbouring 204Hg and wave function configurations for 205Tl consisting of a mixture of quasiparticle ⊗ N-phonon configurations (N=0,1,2), only one group of fragmented dipole excited states has been reproduced at 5.5 MeV in comparison to the experimental distribution which shows a second group at about 5 MeV. The computed dipole transition strengths are mainly of E1 character which could be associated to the pygmy dipole resonance.

Ultraviolet Resonant Raman Enhancements in the Detection of Explosives

Energy Technology Data Exchange (ETDEWEB)

Short Jr., Billy Joe [Naval Postgraduate School, Monterey, CA (United States)

2009-06-01

Raman-based spectroscopy is potentially militarily useful for standoff detection of high explosives. Normal (non-resonance) and resonance Raman spectroscopies are both light scattering techniques that use a laser to measure the vibrational spectrum of a sample. In resonance Raman, the laser is tuned to match the wavelength of a strong electronic absorbance in the molecule of interest, whereas, in normal Raman the laser is not tuned to any strong electronic absorbance bands. The selection of appropriate excitation wavelengths in resonance Raman can result in a dramatic increase in the Raman scattering efficiency of select band(s) associated with the electronic transition. Other than the excitation wavelength, however, resonance Raman is performed experimentally the same as normal Raman. In these studies, normal and resonance Raman spectral signatures of select solid high explosive (HE) samples and explosive precursors were collected at 785 nm, 244 nm and 229 nm. Solutions of PETN, TNT, and explosive precursors (DNT & PNT) in acetonitrile solvent as an internal Raman standard were quantitatively evaluated using ultraviolet resonance Raman (UVRR) microscopy and normal Raman spectroscopy as a function of power and select excitation wavelengths. Use of an internal standard allowed resonance enhancements to be estimated at 229 nm and 244 nm. Investigations demonstrated that UVRR provided ~2000-fold enhancement at 244 nm and ~800-fold improvement at 229 nm while PETN showed a maximum of ~25-fold at 244 nm and ~190-fold enhancement at 229 nm solely from resonance effects when compared to normal Raman measurements. In addition to the observed resonance enhancements, additional Raman signal enhancements are obtained with ultraviolet excitation (i.e., Raman scattering scales as !4 for measurements based on scattered photons). A model, based partly on the resonance Raman enhancement results for HE solutions, is presented for estimating Raman enhancements for solid HE samples.

The interference effects in the alignment and orientation of the Kr II 4p45p states following Kr I 3d9np resonance excitation

International Nuclear Information System (INIS)

Lagutin, B M; Petrov, I D; Sukhorukov, V L; Demekhin, Ph V; Zimmermann, B; Mickat, S; Kammer, S; Schartner, K-H; Ehresmann, A; Shutov, Yu A; Schmoranzer, H

2003-01-01

The energy dependence of the alignment parameter A 20 for the Kr II 4p 4 5p(E 1 J 1 ) states following excitation in the Raman regime with the exciting-photon energy passing through the Kr I 3dJ 9 barnpjbar resonances was investigated theoretically and experimentally. Interference between the resonance and direct photoionization channels explains the dependence of A 20 on the excitation energy. Experimentally, A 20 was determined after the analysis of 5p-5s fluorescence decay of the 4p 4 5p(E 1 J 1 ) states excited with monochromatized synchrotron radiation. The band pass of the synchrotron radiation was set to 10 meV which is smaller than the natural width of the 3d 9 np resonances (∼83 meV). Additionally, a strong energy dependence was predicted for the orientation parameter O 10 as well as for the angular distribution parameter of photoelectrons, β e , for several 4p 4 5p(E 1 J 1 ) ionic states

Resonantly enhanced collisional ionization measurements of radionuclides

International Nuclear Information System (INIS)

Whitaker, T.J.; Bushaw, B.A.; Gerke, G.K.

1986-01-01

The authors developed a new laser technique to analyze for radionuclides at extremely low levels. The technique, called resonantly enhanced collisional ionization (RECI), uses two nitrogen-laser pumped dye lasers to excite the target isotope to a high-energy Rydberg state. Atoms in these Rydberg states (within a few hundred wavenumbers in energy from the ionization threshold) efficiently ionize upon colliding with an inert gas and the ions can be detected by conventional means. The principal advantage of resonantly-enhanced collisional ionization is the extreme sensitivity coupled with its relative simplicity and low cost. Actinides typically have an ionization potential of about 6eV (uranium I.P. = 6.2 eV, plutonium I.P. = 5.7 eV). Two-step laser excitation to a state just below threshold requires wavelengths in the blue region of the visible spectrum. They showed that when both steps in the excitation process are resonant steps, relatively low-power lasers can populate the Rydberg state with almost unit efficiency. This is because the resonant excitations have much larger cross-sections than do photoionization processes. They also demonstrated that a few torr of a buffer gas will cause most of the excited-state atoms to be ionized

Active high-power RF pulse compression using optically switched resonant delay lines

International Nuclear Information System (INIS)

Tantawi, S.G.; Ruth, R.D.; Vlieks, A.E.

1996-11-01

The authors present the design and a proof of principle experimental results of an optically controlled high power rf pulse compression system. The design should, in principle, handle few hundreds of Megawatts of power at X-band. The system is based on the switched resonant delay line theory. It employs resonant delay lines as a means of storing rf energy. The coupling to the lines is optimized for maximum energy storage during the charging phase. To discharge the lines, a high power microwave switch increases the coupling to the lines just before the start of the output pulse. The high power microwave switch, required for this system, is realized using optical excitation of an electron-hole plasma layer on the surface of a pure silicon wafer. The switch is designed to operate in the TE 01 mode in a circular waveguide to avoid the edge effects present at the interface between the silicon wafer and the supporting waveguide; thus, enhancing its power handling capability

Study of the giant multipole resonances, especially the isoscalar giant E2 resonance in 208Pb by inelastic electron scattering with medium and high energy resolution

International Nuclear Information System (INIS)

Kuehner, E.G.F.

1982-01-01

In the nucleus 208 Pb giant multipole resonances were looked for by inelastic electron scattering up to excitation energies of Esub(x) = 35 MeV. Twelve spectra were taken up at incident energies of Esub(o) = 45-65 MeV under scattering angles from upsilon = 93 0 to 165 0 . The cross sections extracted from this were analyzed by means of DWBA calculations using RPA amplitudes from a model with separable residual interaction. Basing on this analysis for the first time it could be shown that the maximum in the electron scattering cross section at Esub(x) approx.= 14 MeV can be consistently described as a superposition of the Jsup(π) = 1 - , ΔT = 1 with a Jsup(π) = 0 + , ΔT = 0 giant resonance. Furthermore the spectra under backward scattering angles indicate the existence of a magnetic excitation at Esub(x) approx.= 15 MeV which is interpreted as Jsup(π) = 3 + giant resonance. Besides under forwards angles a further weak excitation appears at Esub(x) approx.= 14.6 MeV which is very well compatible with Jsup(π) = 2 + . At Esub(x) = 17.5 MeV a Jsup(π) = 3 - resonance was found which recently is also observed in (α,α') scattering experiments and therefore gets a ΔT = 0 assignment. A further resonance at Esub(x) approx.= 21 MeV has also Jsup(π) = 3 - character but has partly to be assigned to a Jsup(π) = 1 - , ΔT = 0 excitation. At Esub(x) = 23.8 MeV a Jsup(π) = 2 + excitation was found which gels because of model predictions a ΔT = 1 assignment. (orig./HSI) [de

Study of the giant multipole resonances especially of the isoscalar giant E2 resonance in 208Pb by medium and high energy resolution inelastic electron scattering

International Nuclear Information System (INIS)

Kuehner, G.

1982-01-01

In the nucleus 208 Pb giant multipole resonances up to excitation energies of Esub(x) = 35 MeV were looked for by medium resolution inelastic electron scattering. Twelve spectra were taken up at incident energies of E 0 = 45-65 MeV under scattering angles from upsilon = 93 0 to 165 0 . The cross sections extracted from this were analyzed by means of DWBA calculations using RPA amplitudes from a model with separable residual interaction. On the base of this analysis for the first time it could be shown that the maximum in the electron scattering cross section at Esub(x) approx.= 14 MeV can be consistently described as superposition of the Jsup(π) = 1 - , ΔT = 1 with a Jsup(π) = 0 + , ΔT = 0 giant resonance. Furthermore the spectra under backward scattering angles indicate the existence of a magnetic excitation at Esub(x) approx.= 15 MeV which is interpreted as Jsup(π) = 3 + giant resonance. Besides under forward angles a further weak excitation at Esub(x) approx.= 14.6 MeV appears which is very well compatible with Jsup(π) = 2 + . At Esub(x) = 17.5 MeV a Jsup(π) = 3 - resonance was found which recently is observed also in (α, α') experiments and therefore gets a ΔT = 0 assignment. A further resonance at Esub(x) approx.= 21 MeV has also a Jsup(π) = 3 - character but has to be partly assigned to a Jsup(π) = 1 - , ΔT = 0 excitation. At Esub(x) = 23.8 MeV a Jsup(π) = 2 + excitation was found which gets because of model predictions a ΔT = 1 assignment. (orig./HSI) [de

Excitation of giant monopole resonance in {sup 208}Pb and {sup 116}Sn using inelastic deuteron scattering

Energy Technology Data Exchange (ETDEWEB)

Patel, D.; Garg, U. [Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States); Joint Institute for Nuclear Astrophysics, University of Notre Dame, Notre Dame, IN 46556 (United States); Itoh, M. [Cyclotron and Radioisotope Center, Tohoku University, Sendai 980-8578 (Japan); Akimune, H. [Department of Physics, Konan University, Kobe 568-8501 (Japan); Berg, G.P.A. [Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States); Joint Institute for Nuclear Astrophysics, University of Notre Dame, Notre Dame, IN 46556 (United States); Fujiwara, M. [Research Center for Nuclear Physics, Osaka University, Osaka 567-0047 (Japan); Harakeh, M.N. [Kernfysisch Versneller Instituut, University of Groningen, 9747 AA Groningen (Netherlands); GANIL, CEA/DSM-CNRS/IN2P3, 14076 Caen (France); Iwamoto, C. [Department of Physics, Konan University, Kobe 568-8501 (Japan); Kawabata, T. [Division of Physics and Astronomy, Kyoto University, Kyoto 606-8502 (Japan); Kawase, K. [Japan Atomic Energy Agency, Kyoto 619-0215 (Japan); Matta, J.T. [Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States); Joint Institute for Nuclear Astrophysics, University of Notre Dame, Notre Dame, IN 46556 (United States); Murakami, T. [Division of Physics and Astronomy, Kyoto University, Kyoto 606-8502 (Japan); Okamoto, A. [Department of Physics, Konan University, Kobe 568-8501 (Japan); Sako, T. [Japan Atomic Energy Agency, Kyoto 619-0215 (Japan); Schlax, K.W. [Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States); Takahashi, F. [Research Center for Nuclear Physics, Osaka University, Osaka 567-0047 (Japan); White, M. [Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States); Yosoi, M. [Research Center for Nuclear Physics, Osaka University, Osaka 567-0047 (Japan)

2014-07-30

The excitation of the isoscalar giant monopole resonance (ISGMR) in {sup 208}Pb and {sup 116}Sn has been investigated using small-angle (including 0°) inelastic scattering of 100 MeV/u deuteron and multipole-decomposition analysis (MDA). The extracted strength distributions agree well with those from inelastic scattering of 100 MeV/u α particles. These measurements establish deuteron inelastic scattering at E{sub d}∼100 MeV/u as a suitable probe for extraction of the ISGMR strength with MDA, making feasible the investigation of this resonance in radioactive isotopes in inverse kinematics.

Survey of the (3He,t) reaction: Excitation of the isobaric analog of the giant dipole resonance

International Nuclear Information System (INIS)

Tabor, S.L.; Chang, C.C.; Collins, M.T.; Wagner, G.J.; Wu, J.R.; Halderson, D.W.; Petrovich, F.

1982-01-01

The ( 3 He,t) reaction at 130 and 170 MeV has been investigated on targets of 12 C, 16 O, 27 Al, 28 Si, 40 Ca, 46 Ti, and 90 Zr. Data for the ( 3 He, 3 He') reaction were measured simultaneously for reference purposes. Structure is observed in the spectra from the ( 3 He, 3 He') and ( 3 He,t) reaction at the expected positions of the giant quadrupole resonance and the isobaric analog of the giant dipole resonance, respectively. An angular distribution was measured for the suspected giant dipole resonance structure in the 40 Ca( 3 He,t) 40 Sc reaction at 130 MeV. The data are reasonably described by a collective model calculation based on the Goldhaber-Teller model for the giant dipole resonance. Several other strong peaks at excitation energies below the giant dipole resonance are observed in the ( 3 He,t) spectra. Most notable of these are the ones at the expected positions for analogs of well known 1 + states and 1hω stretched states in the targets

Magnetophonon resonance in photoluminescence excitation spectra of magnetoexcitons in GaAs/Al0.3Ga0.7As superlattice

DEFF Research Database (Denmark)

Dickmann, S.; Tartakovskii, A. I.; Timofeev, V. B.

2000-01-01

A strong increase in the intensity of the peaks of excited magnetoexciton (ME) states in the photoluminescence excitation (PLE) spectra recorded for the ground heavy-hole magnetoexcitons (of the 1sHH type) has been found in a GaAs/Al0.3Ga0.7As superlattice in strong magnetic field B applied normal...... to the sample layers. While varying B, the intensities of the PLE peaks have been measured as functions of energy separation Delta E between excited ME peaks and the ground state of the system. The resonance profiles have been found to have maxima at Delta E-max close to the energy of the GaAs LO phonon...

Resonance ionization spectroscopy in dysprosium

Energy Technology Data Exchange (ETDEWEB)

Studer, D., E-mail: dstuder@uni-mainz.de; Dyrauf, P.; Naubereit, P.; Heinke, R.; Wendt, K. [Johannes Gutenberg-Universität Mainz, Institut für Physik (Germany)

2017-11-15

We report on resonance ionization spectroscopy (RIS) of high-lying energy levels in dysprosium. We developed efficient excitation schemes and re-determined the first ionization potential (IP) via analysis of Rydberg convergences. For this purpose both two- and three-step excitation ladders were investigated. An overall ionization efficiency of 25(4) % could be demonstrated in the RISIKO mass separator of Mainz University, using a three-step resonance ionization scheme. Moreover, an extensive analysis of the even-parity 6sns- and 6snd-Rydberg-series convergences, measured via two-step excitation was performed. To account for strong perturbations in the observed s-series, the approach of multichannel quantum defect theory (MQDT) was applied. Considering all individual series limits we extracted an IP-value of 47901.76(5) cm{sup −1}, which agrees with the current literature value of 47901.7(6) cm{sup −1}, but is one order of magnitude more precise.

Recent research directions in Fribourg: nuclear dynamics in resonances revealed by 2-dimensional EEL spectra, electron collisions with ionic liquids and electronic excitation of pyrimidine

International Nuclear Information System (INIS)

Allan, M.; Regeta, K.; Gorfinkiel, J.D.; Masin, Z.; Grimme, S.; Bannwarth, C.

2016-01-01

The article briefly reviews three subjects recently investigated in Fribourg: 1) electron collisions with surfaces of ionic liquids, 2) two-dimensional (2D) electron energy loss spectra and 3) resonances in absolute cross sections for electronic excitation of unsaturated compounds. Electron energy loss spectra of four ionic liquids revealed a number of excited states, including triplet states. A solution of a dye in an ionic liquid showed an energy-loss band of the solute, but not in all ionic liquids. 2D spectra reveal state-to-state information (given resonance to given final state) and are shown to be an interesting means to gain insight into dynamics of nuclear motion in resonances. Absolute cross sections for pyrimidine are reported as a function of scattering angle and as a function of electron energy. They reveal resonant structure which was reproduced very nicely by R-matrix calculations. The calculation provided an assignment of the resonances which reveals common patterns in compounds containing double bonds. (authors)

Non-resonant energy harvesting via an adaptive bistable potential

International Nuclear Information System (INIS)

Hosseinloo, Ashkan Haji; Turitsyn, Konstantin

2016-01-01

Narrow bandwidth and easy detuning, inefficiency in broadband and non-stationary excitations, and difficulties in matching a linear harvester’s resonance frequency to low-frequency excitations at small scales, have convinced researchers to investigate nonlinear, and in particular bistable, energy harvesters in recent years. However, bistable harvesters suffer from co-existing low and high energy orbits, and sensitivity to initial conditions, and have recently been proven inefficient when subjected to many real-world random and non-stationary excitations. Here, we propose a novel non-resonant buy-low-sell-high strategy that can significantly improve the harvester’s effectiveness at low frequencies in a much more robust fashion. This strategy could be realized by a passive adaptive bistable system. Simulation results confirm the high effectiveness of the adaptive bistable system following a buy-low-sell-high logic when subjected to harmonic and random non-stationary walking excitations compared to its conventional bistable and linear counterparts. (paper)

Recent experiments involving highly excited atoms

International Nuclear Information System (INIS)

Latimer, C.J.

1979-01-01

Very large and fragile atoms may be produced by exciting normal atoms with light or by collisions with other atomic particles. Atoms as large as 10 -6 m are now routinely produced in the laboratory and their properties studied. In this review some of the simpler experimental methods available for the production and detection of such atoms are described including tunable dye laser-excitation and field ionization. A few recent experiments which illustrate the collision properties and the effects of electric and and magnetic fields are also described. The relevance of highly excited atoms in other areas of research including radioastronomy and isotope separation are discussed. (author)

Ultrafast electrical control of a resonantly driven single photon source

International Nuclear Information System (INIS)

Cao, Y.; Bennett, A. J.; Ellis, D. J. P.; Shields, A. J.; Farrer, I.; Ritchie, D. A.

2014-01-01

We demonstrate generation of a pulsed stream of electrically triggered single photons in resonance fluorescence, by applying high frequency electrical pulses to a single quantum dot in a p-i-n diode under resonant laser excitation. Single photon emission was verified, with the probability of multiple photon emission reduced to 2.8%. We show that despite the presence of charge noise in the emission spectrum of the dot, resonant excitation acts as a “filter” to generate narrow bandwidth photons

Coherent electromagnetic excitation and disintegration of relativistic nuclei passing through crystals

International Nuclear Information System (INIS)

Pivovarov, Yu.L.; Shirokov, A.A.; Vorobiev, S.A.

1990-01-01

The energy dependence of electromagnetic excitation and electromagnetic disintegration cross sections for relativistic nuclei passing through crystals is investigated both theoretically and by means of computer simulation. For electromagnetic excitation, resonant peaks are found at definite energy values. An increase of electromagnetic excitation and disintegration cross sections in crystals at very high energies is found to be due to coherent addition of amplitudes. Numerical results are presented for the electric dipole excitation of fluorine nuclei and electromagnetic deuteron disintegration. (orig.)

Electron-collision excitation cross section of the silver atom

International Nuclear Information System (INIS)

Krasavin, A.Y.; Kuchenev, A.N.; Smirnov, Y.M.

1983-01-01

The cross sections for direct excitation by electron collision were measured for fifteen transitions of the silver atom. For thirteen of these transitions the optical excitation functions were recorded, varying the energy of the exciting electrons from the threshold energy to 250 eV. The operating region of the spectrum was 2000--5500 A. The excitation cross sections of the two principal lines exceeded the excitation cross sections of all the remaining lines by more than an order of magnitude. Reabsorption of the resonance lines was detected from the change in the ratio of intensities of the lines at 3280.68 and 3382.89 A, and so their intensity has been corrected relative to the intensities of the nonreabsorbed lines. All radiative transitions, with the exception of resonance transitions, participate in cascade population of the lowest resonance levels, making it possible to determine the resulting direct excitation cross sections of the 5p 2 P/sub 1/2/ and 5p 2 P/sub 3/2/ levels from the ground state of the silver atom. The part played by cascade population of the resonance levels is not large and is 2 P/sub 3/2/ level, and 10% for the 5p 2 P/sub 1/2/ level, of the excitation cross sections of the corresponding resonance transitions

Demonstration of Magnetic Dipole Resonances of Dielectric Nanospheres in the Visible Region

DEFF Research Database (Denmark)

Evlyukhin, A. B.; Novikov, S. M.; Zywietz, U.

2012-01-01

Strong resonant light scattering by individual spherical Si nanoparticles is experimentally demonstrated, revealing pronounced resonances associated with the excitation of magnetic and electric modes in these nanoparticles. It is shown that the low-frequency resonance corresponds to the magnetic...... dipole excitation. Due to high permittivity, the magnetic dipole resonance is observed in the visible spectral range for Si nanoparticles with diameters of similar to 200 nm, thereby opening a way to the realization of isotropic optical metamaterials with strong magnetic responses in the visible region....

Higher Order Modes Excitation of Micro Cantilever Beams

KAUST Repository

Jaber, Nizar

2014-05-01

In this study, we present analytical and experimental investigation of electrically actuated micro cantilever based resonators. These devices are fabricated using polyimide and coated with chrome and gold layers from both sides. The cantilevers are highly curled up due to stress gradient, which is a common imperfection in surface micro machining. Using a laser Doppler vibrometer, we applied a noise signal to experimentally find the first four resonance frequencies. Then, using a data acquisition card, we swept the excitation frequency around the first four natural modes of vibrations. Theoretically, we derived a reduced order model using the Galerkin method to simulate the dynamics of the system. Extensive numerical analysis and computations were performed. The numerical analysis was able to provide good matching with experimental values of the resonance frequencies. Also, we proved the ability to excite higher order modes using partial electrodes with shapes that resemble the shape of the mode of interest. Such micro-resonators are shown to be promising for applications in mass and gas sensing.

Probing single magnon excitations in Sr2IrO4 using O K-edge resonant inelastic x-ray scattering

International Nuclear Information System (INIS)

Liu, X; Ding, H; Dean, M P M; Yin, W G; Hill, J P; Liu, J; Ramesh, R; Chiuzbăian, S G; Jaouen, N; Nicolaou, A; Serrao, C Rayan

2015-01-01

Resonant inelastic x-ray scattering (RIXS) at the L-edge of transition metal elements is now commonly used to probe single magnon excitations. Here we show that single magnon excitations can also be measured with RIXS at the K-edge of the surrounding ligand atoms when the center heavy metal elements have strong spin–orbit coupling. This is demonstrated with oxygen K-edge RIXS experiments on the perovskite Sr 2 IrO 4 , where low energy peaks from single magnon excitations were observed. This new application of RIXS has excellent potential to be applied to a wide range of magnetic systems based on heavy elements, for which the L-edge RIXS energy resolution in the hard x-ray region is usually poor. (fast track communication)

Resonance Raman scattering of β-carotene solution excited by visible laser beams into second singlet state.

Science.gov (United States)

Lu, Luyao; Shi, Lingyan; Secor, Jeff; Alfano, Robert

2018-02-01

This study aimed to use self-absorption correction to determine the Raman enhancement of β-carotene. The Raman spectra of β-carotene solutions were measured using 488nm, 514nm, 532nm and 633nm laser beams, which exhibited significant resonance Raman (RR) enhancement when the laser energy approaches the electronic transition energy from S 0 to S 2 state. The Raman intensity and the actual resonance Raman gain without self-absorption from S 2 state by β-carotene were also obtained to evaluate the effect of self-absorption on RR scattering. Moreover, we observed the Raman intensity strength followed the absorption spectra. Our study found that, although 488nm and 514nm pumps seemed better for stronger RR enhancement, 532nm would be the optimum Raman pump laser with moderate RR enhancement due to reduced fluorescence and self-absorption. The 532nm excitation will be helpful for applying resonance Raman spectroscopy to investigate biological molecules in tissues. Copyright © 2017 Elsevier B.V. All rights reserved.

Gaussian basis sets for highly excited and resonance states of helium

Czech Academy of Sciences Publication Activity Database

Kaprálová-Žďánská, Petra Ruth; Šmydke, Jan

2013-01-01

Roč. 138, č. 2 (2013), 024105 ISSN 0021-9606 R&D Projects: GA AV ČR IAAX00100903; GA MŠk(CZ) ME10046; GA ČR GAP205/11/0571 Institutional support: RVO:68378271 Keywords : approximation theory * Gaussian processes * ground states * helium neutral atoms * optimisation * resonant states * Rydberg states Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 3.122, year: 2013

Efficient excitation of nonlinear phonons via chirped pulses: Induced structural phase transitions

Science.gov (United States)

Itin, A. P.; Katsnelson, M. I.

2018-05-01

Nonlinear phononics play important role in strong laser-solid interactions. We discuss a dynamical protocol for efficient phonon excitation, considering recent inspiring proposals: inducing ferroelectricity in paraelectric perovskites, and inducing structural deformations in cuprates [Subedi et al., Phys. Rev. B 89, 220301(R) (2014), 10.1103/PhysRevB.89.220301; Phys. Rev. B 95, 134113 (2017), 10.1103/PhysRevB.95.134113]. High-frequency phonon modes are driven by midinfrared pulses, and coupled to lower-frequency modes those indirect excitations cause structural deformations. We study in more detail the case of KTaO3 without strain, where it was not possible to excite the needed low-frequency phonon mode by resonant driving of the higher frequency one. Behavior of the system is explained using a reduced model of coupled driven nonlinear oscillators. We find a dynamical mechanism which prevents effective excitation at resonance driving. To induce ferroelectricity, we employ driving with sweeping frequency, realizing so-called capture into resonance. The method can be applied to many other related systems.

Detection of leak-defective fuel rods using the circumferential Lamb waves excited by the resonance backscattering of ultrasonic pulses

International Nuclear Information System (INIS)

Choi, M.S.; Yang, M.S.; Kim, H.C.

1992-01-01

A new ultrasonic technique for detecting the infiltrated water in leaked fuel rods is developed. Propagation characteristics of the circumferential Lamb waves in the cladding tubes are estimated by the resonance scattering theory. The Lamb waves are excited by the resonance backscattering of ultrasonic pulses. In sound fuel rods, the existence of the Lamb waves is revealed by a series of periodic echoes. In leaked fuel rods, however, the Lamb waves are perturbed strongly by the scattered waves from the surface of fuel pellets, thus the periodic echoes are not observed. (author)

On-Demand Single Photons with High Extraction Efficiency and Near-Unity Indistinguishability from a Resonantly Driven Quantum Dot in a Micropillar

DEFF Research Database (Denmark)

Ding, Xing; He, Yu; Duan, Z.-C.

2016-01-01

Scalable photonic quantum technologies require on-demand single-photon sources with simultaneously high levels of purity, indistinguishability, and efficiency. These key features, however, have only been demonstrated separately in previous experiments. Here, by s-shell pulsed resonant excitation ...

Effective excitation of DBD lamp with a long feedline

International Nuclear Information System (INIS)

Schitz, D V; Nechoroshev, V O

2016-01-01

The proposed solution makes possible the transfer of high-voltage excitation pulses through the long coaxial cable with the minimum losses and the excilamp efficiency. Use of resonant topology of the pulse converter provides ZCS at switching-ON and ZVC at switching- OFF of the transistors. The values of efficiency of radiation of ∼ 9% at the feedline of 2.5 m in length obtained during the experiments are about twice as much as the efficiency at the XeCl- excilamp excitation by the quasi-square pulses power supply due to the decrease of losses at switching and the increase of electric efficiency of a resonant power supply with the long coaxial feedline. (paper)

Total cross section of highly excited strings

International Nuclear Information System (INIS)

Lizzi, F.; Senda, I.

1990-01-01

The unpolarized total cross section for the joining of two highly excited strings is calculated. The calculation is performed by taking the average overall states in the given excitation levels of the initial strings. We find that the total cross section grows with the energy and momentum of the initial states. (author). 8 refs, 1 fig

Intermediate resonance excitation in the {gamma}p->p{pi}{sup 0}{pi}{sup 0} reaction

Energy Technology Data Exchange (ETDEWEB)

Ahrens, J. [Institut fuer Kernphysik, Universitaet Mainz, D-55099 Mainz (Germany); Altieri, S. [INFN, Sezione di Pavia, I-27100 Pavia (Italy); Dipartimento di Fisica Nucleare e Teorica, Universita di Pavia, I-27100 Pavia (Italy); Annand, J.R.M. [Department of Physics and Astronomy, University of Glasgow (United Kingdom)] (and others)

2005-09-29

The helicity dependence of the total cross section for the {gamma}->p->->p{pi}{sup 0}{pi}{sup 0} reaction has been measured for the first time at incident photon energies from 400 to 800 MeV. The measurement, performed at the tagged photon beam facility of the MAMI accelerator in Mainz, used the large acceptance detector DAPHNE and a longitudinally polarized frozen-spin target. This channel is found to be excited predominantly when the photon and proton have a parallel spin orientation, most likely due to the intermediate production of the D{sub 13}(1520) resonance. However, the contribution of the antiparallel spin configuration, arising from other reaction mechanisms, is also not negligible. This result gives important new information to resolve the existing model discrepancies in the identification of the nucleon resonances contributing to this channel.

Electron excitation of alkali atoms

International Nuclear Information System (INIS)

Ormonde, S.

1979-02-01

The development and testing of a synthesized close-coupling effective model potential ten-channel electron-atom scattering code and some preliminary calculations of resonances in cross sections for the excitation of excited states of potassium by low energy electrons are described. The main results obtained are: identification of 1 S and 1 D structures in excitation cross sections below the 5 2 S threshold of neutral potassium; indications of additional structures - 1 P and 1 D between the 5 2 S and 5 2 D thresholds; and a suggested explanation of anomalously high interstate-electron impact excitation cross sections inferred from experiments on potassium-seeded plasmas. The effective potential model imbedded in the code can be used to simulate any atomic system that can be approximated by a single bound electron outside an ionic core. All that is needed is a set of effective potential parameters--experimental or theoretical. With minor modifications the code could be adapted to calculations of electron scattering by two-electron systems

Synchronization of Two Non-Identical Coupled Exciters in a Non-Resonant Vibrating System of Linear Motion. Part I: Theoretical Analysis

Directory of Open Access Journals (Sweden)

Chunyu Zhao

2009-01-01

Full Text Available In this paper an analytical approach is proposed to study the feature of frequency capture of two non-identical coupled exciters in a non-resonant vibrating system. The electromagnetic torque of an induction motor in the quasi-steady-state operation is derived. With the introduction of two perturbation small parameters to average angular velocity of two exciters and their phase difference, we deduce the Equation of Frequency Capture by averaging two motion equations of two exciters over their average period. It converts the synchronization problem of two exciters into that of existence and stability of zero solution for the Equation of Frequency Capture. The conditions of implementing frequency capture and that of stabilizing synchronous operation of two motors have been derived. The concept of torque of frequency capture is proposed to physically explain the peculiarity of self-synchronization of the two exciters. An interesting conclusion is reached that the moments of inertia of the two exciters in the Equation of Frequency Capture reduce and there is a coupling moment of inertia between the two exciters. The reduction of moments of inertia and the coupling moment of inertia have an effect on the stability of synchronous operation.

Simultaneous electrical and mechanical resonance drive for large signal amplification of micro resonators

KAUST Repository

Hasan, M. H.

2018-01-12

Achieving large signal-noise ratio using low levels of excitation signal is key requirement for practical applications of micro and nano electromechanical resonators. In this work, we introduce the double electromechanical resonance drive concept to achieve an order-of-magnitude dynamic signal amplification in micro resonators. The concept relies on simultaneously activating the micro-resonator mechanical and electrical resonance frequencies. We report an input voltage amplification up to 15 times for a micro-resonator when its electrical resonance is tuned to match the mechanical resonance that leads to dynamic signal amplification in air (Quality factor enhancement). Furthermore, using a multi-frequency excitation technique, input voltage and vibrational amplification of up to 30 times were shown for the same micro-resonator while relaxing the need to match its mechanical and electrical resonances.

Simultaneous electrical and mechanical resonance drive for large signal amplification of micro resonators

KAUST Repository

Hasan, M. H.; Alsaleem, F. M.; Jaber, Nizar; Hafiz, Md Abdullah Al; Younis, Mohammad I.

2018-01-01

Achieving large signal-noise ratio using low levels of excitation signal is key requirement for practical applications of micro and nano electromechanical resonators. In this work, we introduce the double electromechanical resonance drive concept to achieve an order-of-magnitude dynamic signal amplification in micro resonators. The concept relies on simultaneously activating the micro-resonator mechanical and electrical resonance frequencies. We report an input voltage amplification up to 15 times for a micro-resonator when its electrical resonance is tuned to match the mechanical resonance that leads to dynamic signal amplification in air (Quality factor enhancement). Furthermore, using a multi-frequency excitation technique, input voltage and vibrational amplification of up to 30 times were shown for the same micro-resonator while relaxing the need to match its mechanical and electrical resonances.

Energy dependence of the ionization of highly excited atoms by collisions with excited atoms

International Nuclear Information System (INIS)

Shirai, T.; Nakai, Y.; Nakamura, H.

1979-01-01

Approximate analytical expressions are derived for the ionization cross sections in the high- and low-collision-energy limits using the improved impulse approximation based on the assumption that the electron-atom inelastic-scattering amplitude is a function only of the momentum transfer. Both cases of simultaneous excitation and de-excitation of one of the atoms are discussed. The formulas are applied to the collisions between two excited hydrogen atoms and are found very useful for estimating the cross sections in the wide range of collisions energies

Ultra-broadband and high-efficiency polarization conversion metasurface with multiple plasmon resonance modes

Science.gov (United States)

Dong, Guo-Xiang; Shi, Hong-Yu; Xia, Song; Li, Wei; Zhang, An-Xue; Xu, Zhuo; Wei, Xiao-Yong

2016-08-01

In this paper, we present a novel metasurface design that achieves a high-efficiency ultra-broadband cross polarization conversion. The metasurface is composed of an array of unit resonators, each of which combines an H-shaped structure and two rectangular metallic patches. Different plasmon resonance modes are excited in unit resonators and allow the polarization states to be manipulated. The bandwidth of the cross polarization converter is 82% of the central frequency, covering the range from 15.7 GHz to 37.5 GHz. The conversion efficiency of the innovative new design is higher than 90%. At 14.43 GHz and 40.95 GHz, the linearly polarized incident wave is converted into a circularly polarized wave. Project supported by the National Natural Science Foundation of China (Grant Nos. 61471292, 61331005, 61471388, 51277012, 41404095, and 61501365), the 111 Project, China (Grant No. B14040), the National Basic Research Program of China (Grant No. 2015CB654602), and the China Postdoctoral Science Foundation ( Grant No. 2015M580849).

Self-excited vibration control for axially fast excited beam by a time delay state feedback

International Nuclear Information System (INIS)

Hamdi, Mustapha; Belhaq, Mohamed

2009-01-01

This work examines the control of self-excited vibration of a simply-supported beam subjected to an axially high-frequency excitation. The investigation of the resonant cases are not considered in this paper. The control is implemented via a corrective position feedback with time delay. The objective of this control is to eliminate the undesirable self-excited vibrations with an appropriate choice of parameters. The issue of stability is also addressed in this paper. Using the technique of direct partition of motion, the dynamic of discretized equations is separated into slow and fast components. The multiple scales method is then performed on the slow dynamic to obtain a slow flow for the amplitude and phase. Analysis of this slow flow provides analytical approximations locating regions in parameters space where undesirable self-excited vibration can be eliminated. A numerical study of these regions is performed on the original discretized system and compared to the analytical prediction showing a good agreement.

High excitation ISM and gas

NARCIS (Netherlands)

Peeters, E; Martinez-Hernandez, NL; Rodriguez-Fernandez, NJ; Tielens, [No Value

An overview is given of ISO results on regions of high excitation ISM and gas, i.e. H II regions, the Galactic Centre and Supernova Remnants. IR emission due to fine-structure lines, molecular hydrogen, silicates, polycyclic aromatic hydrocarbons and dust are summarised, their diagnostic

A Coupled Resonator for Highly Tunable and Amplified Mixer/Filter

KAUST Repository

Ilyas, Saad; Jaber, Nizar; Younis, Mohammad I.

2017-01-01

We present an H-shaped resonator made of two clamped-clamped microbeams mechanically coupled at the middle with a strong coupler to achieve, in a single device, mechanical amplification of the response signal, filtering, and frequency conversion simultaneously. Using mechanical amplification combined with combination resonances generated from a mixed-frequency excitation, a wideband tunable filter, and a simultaneous frequency up and down convertors at multiple bands is demonstrated. The proposed coupled structure, when combined with the easy-to-implement technique of frequency mixing, is promising for applications in an RF chain.

A Coupled Resonator for Highly Tunable and Amplified Mixer/Filter

KAUST Repository

Ilyas, Saad

2017-04-25

We present an H-shaped resonator made of two clamped-clamped microbeams mechanically coupled at the middle with a strong coupler to achieve, in a single device, mechanical amplification of the response signal, filtering, and frequency conversion simultaneously. Using mechanical amplification combined with combination resonances generated from a mixed-frequency excitation, a wideband tunable filter, and a simultaneous frequency up and down convertors at multiple bands is demonstrated. The proposed coupled structure, when combined with the easy-to-implement technique of frequency mixing, is promising for applications in an RF chain.

Excitation transfer in two two-level systems coupled to an oscillator

International Nuclear Information System (INIS)

Hagelstein, P L; Chaudhary, I U

2008-01-01

We consider a generalization of the spin-boson model in which two different two-level systems are coupled to an oscillator, under conditions where the oscillator energy is much less than the two-level system energies, and where the oscillator is highly excited. We find that the two-level system transition energy is shifted, producing a Bloch-Siegert shift in each two-level system similar to what would be obtained if the other were absent. At resonances associated with energy exchange between a two-level system and the oscillator, the level splitting is about the same as would be obtained in the spin-boson model at a Bloch-Siegert resonance. However, there occur resonances associated with the transfer of excitation between one two-level system and the other, an effect not present in the spin-boson model. We use a unitary transformation leading to a rotated system in which terms responsible for the shift and splittings can be identified. The level splittings at the anticrossings associated with both energy exchange and excitation transfer resonances are accounted for with simple two-state models and degenerate perturbation theory using operators that appear in the rotated Hamiltonian

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

High-Q micromechanical resonators for mass sensing in dissipative media

International Nuclear Information System (INIS)

Tappura, Kirsi; Pekko, Panu; Seppä, Heikki

2011-01-01

Single crystal silicon-based micromechanical resonators are developed for mass sensing in dissipative media. The design aspects and preliminary characterization of the resonators are presented. For the suggested designs, quality factors of about 20 000 are typically measured in air at atmospheric pressure and 1000–2000 in contact with liquid. The performance is based on a wine-glass-type lateral bulk acoustic mode excited in a rectangular resonator plate. The mode essentially eliminates the radiation of acoustic energy into the sample media leaving viscous drag as the dominant fluid-based dissipation mechanism in the system. For a mass loading distributed over the central areas of the resonator a sensitivity of 27 ppm ng −1 is measured exhibiting good agreement with the results of the finite element method-based simulations. It is also shown that the mass sensitivity can be somewhat enhanced, not only by the proper distribution of the loaded mass, but also by introducing shallow barrier structures on the resonator

Novel spin excitation in the high field phase of an S=1 antiferromagnetic chain

International Nuclear Information System (INIS)

Hagiwara, M.; Kashiwagi, T.; Kimura, S.; Honda, Z.; Kindo, K.

2007-01-01

We report the results of high-field multi-frequency ESR experiment on the S=1 Heisenberg antiferromagnetic chain Ni(C 5 H 14 N 2 ) 2 N 3 (PF 6 ) for the fields up to about 55T and the frequencies up to about 2THz. We have found that excitation branches above the critical field (H c ) where the energy gap closes change into one branch around 15T which becomes close to the paramagnetic line at high fields. The branch above 15T fits well the conventional antiferromagnetic resonance mode with easy planar anisotropy. We compare the results with those in a weakly coupled antiferromagnetic dimer compound KCuCl 3 and discuss the origin of the branches observed above H c

Magnetic resonance imaging apparatus

International Nuclear Information System (INIS)

Ehnholm, G.J.

1991-01-01

This patent describes an electron spin resonance enhanced magnetic resonance (MR) imaging (ESREMRI) apparatus able to generate a primary magnetic field during periods of nuclear spin transition excitation and magnetic resonance signal detection. This allows the generation of ESREMRI images of a subject. A primary magnetic field of a second and higher value generated during periods of nuclear spin transition excitation and magnetic resonance signal detection can be used to generate conventional MR images of a subject. The ESREMRI and native MR images so generated may be combined, (or superimposed). (author)

Nonlinear dynamics of trions under strong optical excitation in monolayer MoSe2.

Science.gov (United States)

Ye, Jialiang; Yan, Tengfei; Niu, Binghui; Li, Ying; Zhang, Xinhui

2018-02-05

By employing ultrafast transient reflection measurements based on two-color pump-probe spectroscopy, the population and valley polarization dynamics of trions in monolayer MoSe 2 were investigated at relatively high excitation densities under near-resonant excitation. Both the nonlinear dynamic photobleaching of the trion resonance and the redshift of the exciton resonance were found to be responsible for the excitation-energy- and density-dependent transient reflection change as a result of many-body interactions. Furthermore, from the polarization-resolved measurements, it was revealed that the initial fast population and polarization decay process upon strong photoexcitation observed for trions was determined by trion formation, transient phase-space filling and the short valley lifetime of excitons. The results provide a basic understanding of the nonlinear dynamics of population and valley depolarization of trions, as well as exciton-trion correlation in atomically thin MoSe 2 and other transition metal dichalcogenide materials.

Photon energy dependence of left-right asymmetry parameters of Kr 4p photoelectrons in the vicinity of 3d resonant excitations

International Nuclear Information System (INIS)

Ricz, S.; Holste, K.; Borovik, Jr.A.A.; Bernhardt, D.; Schippers, S.; Muller, A.; Kover, A.; Varga, D.

2011-01-01

Complete text of publication follows. A left-right asymmetry was observed experimentally for the outer s-shell photoelectrons of noble gases and of the H 2 molecule in our previous studies (see the cited articles for the definition of 'left' and 'right' as well as for the details of the experimental method). Recently, the angular distribution of 4p photoelectrons of Kr was measured with linearly polarized synchrotron radiation in the photon energy range (90 - 94.4 eV) of the 3d -1 → np resonant excitations in order to determine the anisotropy parameters. Now, also the left-right asymmetry parameters have been determined from the measured spectra of Ref. [3]. The experiment was performed at beamline BW3 of the DORIS III storage ring at HASYLAB (Hamburg, Germany). The emitted electrons were analyzed using the ESA-22D electrostatic electron spectrometer. Fig. 1 shows the measured left-right asymmetry parameters (A LR ) of the two fine structure components of Kr 4p photoelectrons. The asymmetry parameters (A LR ) are increasing with increasing photon energies reaching a maximum value of 0.04, definitely different from zero when considering the error bars. Furthermore, the left-right asymmetry parameters oscillate around the (3d 3/2,5/2 ) -1 → 5p resonant excitation for both fine structure components. Currently, we do not know what kind of interaction can produce a left-right asymmetry in photon-atom collisions but the shape of the oscillations shows interference between the unknown and the resonant excitation channels. One of the most important observations is that the sign of A LR changes from positive to negative and then back again to positive just within a narrow photon energy range of only 250 meV around the (3d 5/2 ) -1 → 5p resonant excitation. Within such a narrow range artificial asymmetry of the experimental setup is totally unconceivable. Acknowledgements. The authors thank the DORIS III staff for providing excellent working conditions. This work was

Design and development of a parametrically excited nonlinear energy harvester

International Nuclear Information System (INIS)

Yildirim, Tanju; Ghayesh, Mergen H.; Li, Weihua; Alici, Gursel

2016-01-01

Highlights: • A parametrically broadband energy harvester was fabricated. • Strong softening-type nonlinear behaviour was observed. • Experiments were conducted showing the large bandwidth of the device. - Abstract: An energy harvester has been designed, fabricated and tested based on the nonlinear dynamical response of a parametrically excited clamped-clamped beam with a central point-mass; magnets have been used as the central point-mass which pass through a coil when parametrically excited. Experiments have been conducted for the energy harvester when the system is excited (i) harmonically near the primary resonance; (ii) harmonically near the principal parametric resonance; (iii) by means of a non-smooth periodic excitation. An electrodynamic shaker was used to parametrically excite the system and the corresponding displacement of the magnet and output voltages of the coil were measured. It has been shown that the system displays linear behaviour at the primary resonance; however, at the principal parametric resonance, the motion characteristic of the magnet substantially changed displaying a strong softening-type nonlinearity. Theoretical simulations have also been conducted in order to verify the experimental results; the comparison between theory and experiment were within very good agreement of each other. The energy harvester developed in this paper is capable of harvesting energy close to the primary resonance as well as the principal parametric resonance; the frequency-band has been broadened significantly mainly due to the nonlinear effects as well as the parametric excitation.

Pre-Excitation Studies for Rubidium-Plasma Generation

CERN Document Server

Aladi, M; Barna, I.F.; Czitrovszky, Aladar; Djotyan, Gagik; Dombi, Peter; Dzsotjan, David; FöLdes, Istvan; Hamar, Gergo; Ignacz, Peter; Kedves, Miklos; Kerekes, Attila; Levai, Peter; Marton, Istvan; Nagy, Attila; Oszetzky, Daniel; Pocsai, Mihaly; Racz, Peter; Raczkevi, Bela; Szigeti, Janos; Sörlei, Zsuzsa; Szipöcs, Robert; Varga, Dezso; Varga-Umbrich, Karoly; Varro, Sandor; Vamos, Lenard; Vesztergombi, György

2014-01-01

The key element in the Proton-Driven-Plasma-Wake-Field-Accelerator (AWAKE) project is the generation of highly uniform plasma from Rubidium vapor. The standard way to achieve full ionization is to use high power laser which can assure the over-barrier-ionization (OBI) along the 10 meters long active region. The Wigner-team in Budapest is investigating an alternative way of uniform plasma generation. The proposed Resonance Enhanced Multi Photon Ionization (REMPI) scheme probably can be realized by much less laser power. In the following the resonant pre-excitations of the Rb atoms are investigated, theoretically and the status report about the preparatory work on the experiment are presented.

Highly excited atoms

International Nuclear Information System (INIS)

Kleppner, D.; Littman, M.G.; Zimmerman, M.L.

1981-01-01

Highly excited atoms are often called Rydberg atoms. These atoms have a wealth of exotic properties which are discussed. Of special interest, are the effects of electric and magnetic fields on Rydberg atoms. Ordinary atoms are scarcely affected by an applied electric or magnetic field; Rydberg atoms can be strongly distorted and even pulled apart by a relatively weak electric field, and they can be squeezed into unexpected shapes by a magnetic field. Studies of the structure of Rydberg atoms in electric and magnetic fields have revealed dramatic atomic phenomena that had not been observed before

Theories and experiments on the stiffening effect of high-frequency excitation for continuous elastic systems

DEFF Research Database (Denmark)

Thomsen, Jon Juel

2003-01-01

theories, each providing valuable insight. One of these is capable of predicting the vertical string lift due to stiffening in terms of simple expressions, with results that agree very well with experimental measurements for a wide range of conditions. It appears that resonance effects cannot be ignored...... for demonstrating and measuring the stiffening effect in a simple setting, in the form of a horizontal piano string subjected to longitudinal high-frequency excitation at the clamped base and free at the other end. A simplest possible theoretical model is set up and analyzed using a hierarchy of three approximating......, as was done in a few related studies¿¿unless the system has very low modal density or heavy damping; thus first-order consideration to resonance effects is included. Using the specific example with experimental support to put confidence on the proposed theory, expressions for predicting the stiffening effect...

Acceleration of electrons at wakefield excitation by a sequence of relativistic electron bunches in dielectric resonator

International Nuclear Information System (INIS)

Kiselev, V.A.; Linnik, A.F.; Mirnyj, V.I.; Onishchenko, I.N.; Uskov, V.V.

2009-01-01

Method is proposed to divide a regular sequence of electron bunches into parts of bunches driving wakefield and witness bunches, which should be accelerated. It allows to avoid the necessity of additional electron accelerator for witness bunches producing and the necessity of precision short time techniques of injection phase adjusting. The idea concludes to the frequency detuning between bunches repetition frequency and the frequency of the fundamental mode of excited wakefield. Experiments were carried out on the linear resonant accelerator 'Almaz-2', which injected in the dielectric resonator a sequence of 6000 short bunches of relativistic electrons with energy 4.5 MeV, charge 0.16 nC and duration 60 psec each, the repetition interval 360 ps. Frequency detuning was entered by change of frequency of the master generator of the klystron within the limits of one percent so that the phase taper on the length of bunches sequence achieved 2π. Energy spectra of electrons of bunches sequence, which have been propagated through the dielectric resonator are measured and analyzed

Resonance enhancement of neutrinoless double electron capture

International Nuclear Information System (INIS)

Krivoruchenko, M.I.; Simkovic, Fedor; Frekers, Dieter; Faessler, Amand

2011-01-01

The process of neutrinoless double electron (0νECEC) capture is revisited for those cases where the two participating atoms are nearly degenerate in mass. The theoretical framework is the formalism of an oscillation of two atoms with different total lepton number (and parity), one of which can be in an excited state so that mass degeneracy is realized. In such a case and assuming light Majorana neutrinos, the two atoms will be in a mixed configuration with respect to the weak interaction. A resonant enhancement of transitions between such pairs of atoms will occur, which could be detected by the subsequent electromagnetic de-excitation of the excited state of the daughter atom and nucleus. Available data of atomic masses, as well as nuclear and atomic excitations are used to select the most likely candidates for the resonant transitions. Assuming an effective mass for the Majorana neutrino of 1 eV, some half-lives are predicted to be as low as 10 22 years in the unitary limit. It is argued that, in order to obtain more accurate predictions for the 0νECEC half-lives, precision mass measurements of the atoms involved are necessary, which can readily be accomplished by today's high precision Penning traps. Further advancements also require a better understanding of high-lying excited states of the final nuclei (i.e. excitation energy, angular momentum and parity) and the calculation of the nuclear matrix elements.

High Excitation Gas and ISM

Science.gov (United States)

Peeters, E.; Martin-Hernandez, N. L.; Rodriguez-Fernandez, N. J.; Tielens, A. G. G. M.

2004-01-01

An overview is given of ISO results on regions of high excitation ISM and gas, i.e. HII regions, the Galactic Centre and Supernovae Remnants. IR emission due to fine-structure lines, molecular hydrogen, silicates, polycyclic aromatic hydrocarbons and dust are summarized, their diagnostic capabilities illustrated and their implications highlighted.

Acoustic spin pumping in magnetoelectric bulk acoustic wave resonator

Directory of Open Access Journals (Sweden)

N. I. Polzikova

2016-05-01

Full Text Available We present the generation and detection of spin currents by using magnetoelastic resonance excitation in a magnetoelectric composite high overtone bulk acoustic wave (BAW resonator (HBAR formed by a Al-ZnO-Al-GGG-YIG-Pt structure. Transversal BAW drives magnetization oscillations in YIG film at a given resonant magnetic field, and the resonant magneto-elastic coupling establishes the spin-current generation at the Pt/YIG interface. Due to the inverse spin Hall effect (ISHE this BAW-driven spin current is converted to a dc voltage in the Pt layer. The dependence of the measured voltage both on magnetic field and frequency has a resonant character. The voltage is determined by the acoustic power in HBAR and changes its sign upon magnetic field reversal. We compare the experimentally observed amplitudes of the ISHE electrical field achieved by our method and other approaches to spin current generation that use surface acoustic waves and microwave resonators for ferromagnetic resonance excitation, with the theoretically expected values.

Acoustic spin pumping in magnetoelectric bulk acoustic wave resonator

Energy Technology Data Exchange (ETDEWEB)

Polzikova, N. I., E-mail: polz@cplire.ru; Alekseev, S. G.; Pyataikin, I. I.; Kotelyanskii, I. M.; Luzanov, V. A.; Orlov, A. P. [Kotel’nikov Institute of Radio Engineering and Electronics of Russian Academy of Sciences, Mokhovaya 11, building 7, Moscow, 125009 (Russian Federation)

2016-05-15

We present the generation and detection of spin currents by using magnetoelastic resonance excitation in a magnetoelectric composite high overtone bulk acoustic wave (BAW) resonator (HBAR) formed by a Al-ZnO-Al-GGG-YIG-Pt structure. Transversal BAW drives magnetization oscillations in YIG film at a given resonant magnetic field, and the resonant magneto-elastic coupling establishes the spin-current generation at the Pt/YIG interface. Due to the inverse spin Hall effect (ISHE) this BAW-driven spin current is converted to a dc voltage in the Pt layer. The dependence of the measured voltage both on magnetic field and frequency has a resonant character. The voltage is determined by the acoustic power in HBAR and changes its sign upon magnetic field reversal. We compare the experimentally observed amplitudes of the ISHE electrical field achieved by our method and other approaches to spin current generation that use surface acoustic waves and microwave resonators for ferromagnetic resonance excitation, with the theoretically expected values.

High resolution resonant Raman scattering in InP and GaAs

International Nuclear Information System (INIS)

Kernohan, E.T.M.

1996-04-01

Previous studies of III-V semiconductors using resonant Raman scattering have concentrated on measuring the variations in scattering intensity under different excitation conditions. The shape of the Raman line also contains important information, but this has usually been lost because the low signal strengths mean that resolution has been sacrificed for sensitivity. It might therefore be expected that further insights into the processes involved in Raman scattering could be obtained by using high resolution methods. In this thesis I have measured single- and multiple- phonon scattering from bulk GaAs and InP with a spectral resolution better than the intrinsic widths of the Raman lines. For scattering in the region of one longitudinal optic (LO) phonon energy, it is found that in InP the scattering in the allowed and forbidden configurations occur at different Raman shifts, above and below the zone-centre phonon energy respectively. These shifts are used to determine the scattering processes involved, and how they differ between InP and GaAs. The lineshapes obtained in multiple-phonon scattering are found to depend strongly on the excitation energy used, providing evidence for the presence of intermediate resonances. The measured spectra are used to provide information about the phonon dispersion of InP, whose dispersion it is difficult to measure in any other way, and the first evidence is found for an upward dispersion of the LO mode. Raman lineshapes are measured for InP in a magnetic field. The field alters the electronic bandstructure, leading to a series of strong resonances in the Raman efficiency due to interband magneto-optical transitions between Landau levels. This allows multiphonon processes up to sixth-order to be investigated. (author)

Stark-shift induced resonances in multiphoton ionization

International Nuclear Information System (INIS)

Potvliege, R M; Vuci, Svetlana

2006-01-01

The resonance enhancements marking the ATI spectrum of argon are discussed in the light of a recently compiled map of the quasienergies of this atom. Many of the dressed excited states of interest shift nonponderomotively in complicated ways, but keep an ionization width narrow enough to produce sharp substructures of both low and high ATI peaks through Stark-shift induced resonances. The most prominent enhancement observed in the high-order ATI peaks originates from ionization from the dressed ground state perturbed by the influence of neighbouring resonant dressed states

Excited QCD 2017

CERN Document Server

2017-01-01

This edition is the ninth in a series of workshops that had been previously organised in Poland (2009), Slovakia (2010 and 2015), France (2011), Portugal (2012 and 2016) and Bosnia and Herzegovina (2013 and 2014). In the year 2017 the workshop goes to the beautiful Sintra near Lisbon, Portugal. The workshop covers diverse aspects of QCD: (i) QCD at low energies: excited hadrons, new resonances, glueballs, multiquarks. (ii) QCD at high temperatures and large densities: heavy-ion collisions, jets, diffraction, hadronisation, quark-gluon plasma, holography, colour-glass condensate, compact stars, applications to astrophysics.

Suppression of chaos by weak resonant excitations in a non-linear oscillator with a non-symmetric potential

International Nuclear Information System (INIS)

Litak, Grzegorz; Syta, Arkadiusz; Borowiec, Marek

2007-01-01

We examine the Melnikov criterion for transition to chaos in case of one degree of freedom non-linear oscillator with non-symmetric potential. This system, when subjected to an external periodic force, shows homoclinic transition from regular vibrations to chaos just before escape from a potential well. We focus especially on the effect of a second resonant excitation with a different phase on the system transition to chaos. We propose a way of its control

Dual frequency parametric excitation of a nonlinear, multi degree of freedom mechanical amplifier with electronically modified topology

Science.gov (United States)

Dolev, A.; Bucher, I.

2018-04-01

Mechanical or electromechanical amplifiers can exploit the high-Q and low noise features of mechanical resonance, in particular when parametric excitation is employed. Multi-frequency parametric excitation introduces tunability and is able to project weak input signals on a selected resonance. The present paper addresses multi degree of freedom mechanical amplifiers or resonators whose analysis and features require treatment of the spatial as well as temporal behavior. In some cases, virtual electronic coupling can alter the given topology of the resonator to better amplify specific inputs. An analytical development is followed by a numerical and experimental sensitivity and performance verifications, illustrating the advantages and disadvantages of such topologies.

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

μ-'Diving suit' for liquid-phase high-Q resonant detection.

Science.gov (United States)

Yu, Haitao; Chen, Ying; Xu, Pengcheng; Xu, Tiegang; Bao, Yuyang; Li, Xinxin

2016-03-07

A resonant cantilever sensor is, for the first time, dressed in a water-proof 'diving suit' for real-time bio/chemical detection in liquid. The μ-'diving suit' technology can effectively avoid not only unsustainable resonance due to heavy liquid-damping, but also inevitable nonspecific adsorption on the cantilever body. Such a novel technology ensures long-time high-Q resonance of the cantilever in solution environment for real-time trace-concentration bio/chemical detection and analysis. After the formation of the integrated resonant micro-cantilever, a patterned photoresist and hydrophobic parylene thin-film are sequentially formed on top of the cantilever as sacrificial layer and water-proof coat, respectively. After sacrificial-layer release, an air gap is formed between the parylene coat and the cantilever to protect the resonant cantilever from heavy liquid damping effect. Only a small sensing-pool area, located at the cantilever free-end and locally coated with specific sensing-material, is exposed to the liquid analyte for gravimetric detection. The specifically adsorbed analyte mass can be real-time detected by recording the frequency-shift signal. In order to secure vibration movement of the cantilever and, simultaneously, reject liquid leakage from the sensing-pool region, a hydrophobic parylene made narrow slit structure is designed surrounding the sensing-pool. The anti-leakage effect of the narrow slit and damping limited resonance Q-factor are modelled and optimally designed. Integrated with electro-thermal resonance excitation and piezoresistive frequency readout, the cantilever is embedded in a micro-fluidic chip to form a lab-chip micro-system for liquid-phase bio/chemical detection. Experimental results show the Q-factor of 23 in water and longer than 20 hours liquid-phase continuous working time. Loaded with two kinds of sensing-materials at the sensing-pools, two types of sensing chips successfully show real-time liquid-phase detection to ppb

Current-driven parametric resonance in magnetic multilayers

International Nuclear Information System (INIS)

Wang, C; Seinige, H; Tsoi, M

2013-01-01

Current-induced parametric excitations were observed in point-contact spin-valve nanodevices. Point contacts were used to inject high densities of direct and microwave currents into spin valves, thus producing oscillating spin-transfer and Oersted-field torques on magnetic moments. The resulting magnetodynamics were observed electrically by measuring rectified voltage signals across the contact. In addition to the spin-torque-driven ferromagnetic resonance we observe doubled-frequency signals which correspond to the parametric excitation of magnetic moments. Numerical simulations suggest that while both spin-transfer torque and ac Oersted field contribute to the parametrically excited dynamics, the ac spin torque dominates, and dc spin torque can switch it on and off. The dc bias dependence of the parametric resonance signal enabled the mapping of instability regions characterizing the nonlinearity of the oscillation. (paper)

Development and characterization of high-frequency resonance-enhanced microjet actuators for control of high-speed jets

Science.gov (United States)

Upadhyay, Puja; Gustavsson, Jonas P. R.; Alvi, Farrukh S.

2016-05-01

For flow control applications requiring high-frequency excitation, very few actuators have sufficient dynamic response and/or control authority to be useful in high-speed flows. Due to this reason, experiments involving high-frequency excitation, attempted in the past, have been limited to either low-frequency actuation with reasonable control authority or moderate-frequency actuation with limited control authority. The current work expands on the previous development of the resonance-enhanced microactuators to design actuators that are capable of producing high-amplitude pulses at much higher frequencies [{O} (10 kHz)]. Using lumped element modeling, two actuators have been designed with nominal frequencies of 20 and 50 kHz. Extensive benchtop characterization using acoustic measurements as well as optical diagnostics using a high-resolution micro-schlieren setup is employed to characterize the dynamic response of these actuators. The actuators performed at a range of frequencies, 20.3-27.8 and 54.8-78.2 kHz, respectively. In addition to providing information on the actuator flow physics and performance at various operating conditions, this study serves to develop easy-to-integrate high-frequency actuators for active control of high-speed jets. Preliminary testing of these actuators is performed by implementing the 20-kHz actuator on a Mach 0.9 free jet flow field for noise reduction. Acoustic measurements in the jet near field demonstrate attenuation of radiated noise at all observation angles.

Resonance Raman and surface-enhanced resonance Raman spectra of LH2 antenna complex from Rhodobacter sphaeroides and Ectothiorhodospira sp. excited in the Qx and Qy transitions.

Science.gov (United States)

Chumanov, G; Picorel, R; Ortiz de Zarate, I; Cotton, T M; Seibert, M

2000-05-01

Well-resolved vibrational spectra of LH2 complex isolated from two photosynthetic bacteria, Rhodobacter sphaeroides and Ectothiorhodospira sp., were obtained using surface-enhanced resonance Raman scattering (SERRS) exciting into the Qx and the Qy transitions of bacteriochlorophyll a. High-quality SERRS spectra in the Qy region were accessible because the strong fluorescence background was quenched near the roughened Ag surface. A comparison of the spectra obtained with 590 nm and 752 nm excitation in the mid- and low-frequency regions revealed spectral differences between the two LH2 complexes as well as between the LH2 complexes and isolated bacteriochlorophyll a. Because peripheral modes of pigments contribute mainly to the low-frequency spectral region, frequencies and intensities of many vibrational bands in this region are affected by interactions with the protein. The results demonstrate that the microenvironment surrounding the pigments within the two LH2 complexes is somewhat different, despite the fact that the complexes exhibit similar electronic absorption spectra. These differences are most probably due to specific pigment-pigment and pigment-protein interactions within the LH2 complexes, and the approach might be useful for addressing subtle static and dynamic structural variances between pigment-protein complexes from different sources or in complexes altered chemically or genetically.

High-spin excitations of atomic nuclei

International Nuclear Information System (INIS)

Xu Furong; National Laboratory of Heavy Ion Physics, Lanzhou; Chinese Academy of Sciences, Beijing

2004-01-01

The authors used the cranking shell model to investigate the high-spin motions and structures of atomic nuclei. The authors focus the collective rotations of the A∼50, 80 and 110 nuclei. The A∼50 calculations show complicated g spectroscopy, which can have significant vibration effects. The A≅80 N≅Z nuclei show rich shape coexistence with prolate and oblate rotational bands. The A≅110 nuclei near the r-process path can have well-deformed oblate shapes that become yrast and more stable with increasing rotational frequency. As another important investigation, the authors used the configuration-constrained adiabatic method to calculate the multi-quasiparticle high-K states in the A∼130, 180 and superheavy regions. The calculations show significant shape polarizations due to quasi-particle excitations for soft nuclei, which should be considered in the investigations of high-K states. The authors predicted some important high-K isomers, e.g., the 8 - isomers in the unstable nuclei of 140 Dy and 188 Pb, which have been confirmed in experiments. In superheavy nuclei, our calculations show systematic existence of high-K states. The high-K excitations can increase the productions of synthesis and the survival probabilities of superheavy nuclei. (authors)

Geometrical scaling and modal decay rates in periodic arrays of deeply subwavelength Terahertz resonators

International Nuclear Information System (INIS)

Isić, Goran; Gajić, Radoš

2014-01-01

It is well known that due to the high conductivity of noble metals at terahertz frequencies and scalability of macroscopic Maxwell equations, a geometrical downscaling of a terahertz resonator results in the linear upscaling of its resonance frequency. However, the scaling laws of modal decay rates, important for the resonator excitation efficiency, are much less known. Here, we investigate the extent to which the scale-invariance of decay rates is violated due to the finite conductivity of the metal. We find that the resonance quality factor or the excitation efficiency may be substantially affected by scaling and show that this happens as a result of the scale-dependence of the metal absorption rate, while the radiative decay and the dielectric cavity absorption rates are approximately scale-invariant. In particular, we find that by downscaling overcoupled resonators, their excitation efficiency increases, while the opposite happens with undercoupled resonators

Multiphoton resonances

International Nuclear Information System (INIS)

Shore, B.W.

1977-01-01

The long-time average of level populations in a coherently-excited anharmonic sequence of energy levels (e.g., an anharmonic oscillator) exhibits sharp resonances as a function of laser frequency. For simple linearly-increasing anharmonicity, each resonance is a superposition of various multiphoton resonances (e.g., a superposition of 3, 5, 7, . . . photon resonances), each having its own characteristic width predictable from perturbation theory

NiO as a test case for high resolution resonant inelastic soft x-ray scattering

International Nuclear Information System (INIS)

Ghiringhelli, G; Matsubara, M; Dallera, C; Fracassi, F; Gusmeroli, R; Piazzalunga, A; Tagliaferri, A; Brookes, N B; Kotani, A; Braicovich, L

2005-01-01

Resonant inelastic x-ray scattering (RIXS) at the L 2,3 edges of 3d transition metal compounds has recently become a high resolution spectroscopic technique thanks to improvements in the instrumentation. We have chosen the prototypical case of NiO to explore the various levels of interpretation applicable to L 3 RIXS spectra of strongly correlated electron systems. Starting from a set of experimental data measured across the Ni L 3 absorption edge with 550 meV combined energy resolution, we analyse the rich spectral structure within an atomic framework. The spectra can be separated into dd and charge transfer excitation regions. The dd excitations can be interpreted and well reproduced within a crystal field model. The charge transfer excitations are analysed through the comparison with calculations made in the Anderson impurity model. A series of parameters belonging to the proposed models (crystal field strength, charge transfer energy, hybridization integrals) can thus be extracted in a very direct and unambiguous way

Double excitation of helium by 3 MeV proton impact: experiment and theory

Energy Technology Data Exchange (ETDEWEB)

Bordenave-Montesquieu, A.; Gleizes, A.; Moretto-Capelle, P.; Benoit-Cattin, P. (Toulouse-3 Univ., 31 (France). Centre de Physique Atomique); Andriamonje, S. (Bordeaux-1 Univ., 33 -Gradignan (France)); Martin, F. (Universidad Autonoma de Madrid (Spain). Dept. de Quimica); Salin, A. (Bordeaux-1 Univ., 33 - Talence (France))

1992-08-14

Doubly differential cross sections for the double excitation of helium by high velocity protons are measured and compared with the predictions of the first-order Born approximation. Preliminary experimental data for the shapes and intensities of the resonances 2s[sup 2] [sup 1]S, 2p[sup 2] [sup 1]D and 2s2p [sup 1]P have been obtained from high resolution electron spectra at 20[sup o], 90[sup o] and 150[sup o] for a proton energy of 3 MeV. Both experiment and theory show that the excitation of the [sup 1]P resonance largely exceeds the [sup 1]D and [sup 1]S ones at this collision velocity. The shape and emission yield of the [sup 1]P line is well described by theory over the whole angular range. The agreement for the other two resonances is not always satisfactory. (author).

Magnetic excitations and amplitude fluctuations in insulating cuprates

Science.gov (United States)

Chelwani, N.; Baum, A.; Böhm, T.; Opel, M.; Venturini, F.; Tassini, L.; Erb, A.; Berger, H.; Forró, L.; Hackl, R.

2018-01-01

We present results from light scattering experiments on three insulating antiferromagnetic cuprates, YBa2Cu3O6.05 , Bi2Sr2YCu2O8 +δ , and La2CuO4 as a function of polarization and excitation energy using samples of the latest generation. From the raw data we derive symmetry-resolved spectra. The spectral shape in B1 g symmetry is found to be nearly universal and independent of excitation energy. The spectra agree quantitatively with predictions by field theory [Eur. Phys. J. B 88, 237 (2015), 10.1140/epjb/e2015-60438-1] facilitating the precise extraction of the Heisenberg coupling J . In addition, the asymmetric lineshape on the high-energy side is found to be related to amplitude fluctuations of the magnetization. In La2CuO4 alone, minor contributions from resonance effects may be identified. The spectra in the other symmetries are not universal. The variations may be traced back to weak resonance effects and extrinsic contributions. For all three compounds we find support for the existence of chiral excitations appearing as a continuum in A2 g symmetry having an onset slightly below 3 J . In La2CuO4 an additional isolated excitation appears on top of the A2 g continuum.

Active Radiative Thermal Switching with Graphene Plasmon Resonators.

Science.gov (United States)

Ilic, Ognjen; Thomas, Nathan H; Christensen, Thomas; Sherrott, Michelle C; Soljačić, Marin; Minnich, Austin J; Miller, Owen D; Atwater, Harry A

2018-03-27

We theoretically demonstrate a near-field radiative thermal switch based on thermally excited surface plasmons in graphene resonators. The high tunability of graphene enables substantial modulation of near-field radiative heat transfer, which, when combined with the use of resonant structures, overcomes the intrinsically broadband nature of thermal radiation. In canonical geometries, we use nonlinear optimization to show that stacked graphene sheets offer improved heat conductance contrast between "ON" and "OFF" switching states and that a >10× higher modulation is achieved between isolated graphene resonators than for parallel graphene sheets. In all cases, we find that carrier mobility is a crucial parameter for the performance of a radiative thermal switch. Furthermore, we derive shape-agnostic analytical approximations for the resonant heat transfer that provide general scaling laws and allow for direct comparison between different resonator geometries dominated by a single mode. The presented scheme is relevant for active thermal management and energy harvesting as well as probing excited-state dynamics at the nanoscale.

Gross resonance-like structure of the complete fusion excitation function for the 16O + 28Si reaction

International Nuclear Information System (INIS)

Zheng Jiwen; Zheng Pingzi; Liu Guoxing

1993-01-01

The complete fusion excitation function for the 16 O + 28 Si reaction is measured in the incident energy range from 50 to 90 MeV with step of 1.0 MeV using a position sensitive ΔE-E telescope system. The striking gross resonance-like structure is observed when E c.m. c.m. 34.5, 38.5 and 43.0 MeV respectively. The structure vanishes gradually when E c.m. > 46.0 MeV

High quality-factor optical resonators

International Nuclear Information System (INIS)

Henriet, Rémi; Salzenstein, Patrice; Coillet, Aurélien; Saleh, Khaldoun; Chembo, Yanne K; Ristic, Davor; Ferrari, Maurizio; Mortier, Michel; Rasoloniaina, Alphonse; Dumeige, Yannick; Féron, Patrice; Cibiel, Gilles; Llopis, Olivier

2014-01-01

Various resonators are investigated for microwave photonic applications. Micro-sphere, disk and fiber ring resonators were designed, realized and characterized. Obtained quality factors are as high as Q = 10 10 . (paper)

Experimental REMPI [Resonance Enhanced Multiphoton Ionization] studies of small molecules

International Nuclear Information System (INIS)

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

1986-01-01

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 exciting opportunities for both basic and applied science. On the applied side, REMPI has great potential as an ultrasensitive, highly selective detector for trace, reactive, or transient species. On the basic side, REMPI affords an unprecedented means of exploring excited state physics and chemistry at the quantum-state-specific level. We shall give an overview together with examples of current studies of excited molecular states to illustrate the principles of and prospects for REMPI. 27 refs., 3 figs

Dissociation dynamics of anionic and excited neutral fragments of gaseous SiCl4 following Cl 2p and Si 2p core-level excitations

International Nuclear Information System (INIS)

Chen, J M; Lu, K T; Lee, J M; Chou, T L; Chen, H C; Chen, S A; Haw, S C; Chen, T H

2008-01-01

The state-selective dissociation dynamics for anionic and excited neutral fragments of gaseous SiCl 4 following Cl 2p and Si 2p core-level excitations were characterized by combining measurements of the photon-induced anionic dissociation, x-ray absorption and UV/visible dispersed fluorescence. The transitions of core electrons to high Rydberg states/doubly excited states in the vicinity of both Si 2p and Cl 2p ionization thresholds of gaseous SiCl 4 lead to a remarkably enhanced production of anionic, Si - and Cl - , fragments and excited neutral atomic, Si*, fragments. This enhancement via core-level excitation near the ionization threshold of gaseous SiCl 4 is explained in terms of the contributions from the Auger decay of doubly excited states, shake-modified resonant Auger decay, or/and post-collision interaction. These complementary results provide insight into the state-selective anionic and excited neutral fragmentation of gaseous molecules via core-level excitation.

Studies of isovector excitations in nuclei by neutron-induced reactions

International Nuclear Information System (INIS)

Nilsson, L.

1987-01-01

In this paper isovector excitations in nuclei, in particular the giant isovector quadrupole resonance in spherical nuclei, will be discussed. Several methods to investigate this excitation have been used, e.g. inelastic electron scattering and charge-exchange reactions. An alternative method to study isovector E2 resonances in nuclei, based on the radiative capture of fast neutrons, will be presented. Results from such experiments performed at the tandem accelerator laboratories in Los Alamos and Uppsala will be presented and discussed in terms of the direct-semidirect capture model. As a separate issue, the preparations being undertaken at Uppsala for studies of isovector excitations in nuclei by means of the (n,p) reaction will be described. A schematic lay-out of the experiment will be presented together with some relevant neutron beam parameters. Among isovector excitations to be studied by this method are the isovector monopole resonance and the Gamow-Teller resonance. 54 references, 6 figures, 1 table

Synchronization of Two Non-Identical Coupled Exciters in a Non-Resonant Vibrating System of Linear Motion. Part II: Numeric Analysis

Directory of Open Access Journals (Sweden)

Chunyu Zhao

2009-01-01

Full Text Available The paper focuses on the quantitative analysis of the coupling dynamic characteristics of two non-identical exciters in a non-resonant vibrating system. The load torque of each motor consists of three items, including the torque of sine effect of phase angles, that of coupling sine effect and that of coupling cosine effect. The torque of frequency capture results from the torque of coupling cosine effect, which is equal to the product of the coupling kinetic energy, the coefficient of coupling cosine effect, and the sine of phase difference of two exciters. The motions of the system excited by two exciters in the same direction make phase difference close to π and that in opposite directions makes phase difference close to 0. Numerical results show that synchronous operation is stable when the dimensionless relative moments of inertia of two exciters are greater than zero and four times of their product is greater than the square of their coefficient of coupling cosine effect. The stability of the synchronous operation is only dependent on the structural parameters of the system, such as the mass ratios of two exciters to the vibrating system, and the ratio of the distance between an exciter and the centroid of the system to the equivalent radius of the system about its centroid.

Inductive measurements of ferromagnetic resonance

International Nuclear Information System (INIS)

Woodward, R.C.; Kennewell, K.; Crew, D.C.; Stamps, R.L.

2004-01-01

Full text: The rapid advance in magnetic data storage has driven groundbreaking work in the science that underpins the properties of ferromagnetic materials at high frequencies. Recent work in this area has included the use of precession in order to produce ultra-high speed switching of magnetic elements, the generation of excited dynamical structures by application of inhomogeneous field pulses, and examination of the propagation of localized spin waves. This paper describes explorations of ultra-fast magnetization dynamics being undertaken at The University of Western Australia. We have studied the differences in magnetization dynamics in simple permalloy films when a sample is excited with sharp pulse compared to the to the dynamics generated by the application of a small amplitude continuous wave signal. We have observed a difference in the resonant frequency determined from these two excitations and will propose reasons for the different resonance responses of the system. Using the ultra-fast techniques described above we have measured dynamical properties that are significantly different to the static properties. These results are explained by the dynamical measurements being made on time scales smaller than the characteristic relaxation time. Future applications of these devices will be to examine broadening of line widths and frequency shifts associated with the excitation of magnetostatic modes, factors limiting quasiballistic reversal and differences between the dynamic and static properties of magnetic materials

Micro-machined resonator oscillator

Science.gov (United States)

Koehler, Dale R.; Sniegowski, Jeffry J.; Bivens, Hugh M.; Wessendorf, Kurt O.

1994-01-01

A micro-miniature resonator-oscillator is disclosed. Due to the miniaturization of the resonator-oscillator, oscillation frequencies of one MHz and higher are utilized. A thickness-mode quartz resonator housed in a micro-machined silicon package and operated as a "telemetered sensor beacon" that is, a digital, self-powered, remote, parameter measuring-transmitter in the FM-band. The resonator design uses trapped energy principles and temperature dependence methodology through crystal orientation control, with operation in the 20-100 MHz range. High volume batch-processing manufacturing is utilized, with package and resonator assembly at the wafer level. Unique design features include squeeze-film damping for robust vibration and shock performance, capacitive coupling through micro-machined diaphragms allowing resonator excitation at the package exterior, circuit integration and extremely small (0.1 in. square) dimensioning. A family of micro-miniature sensor beacons is also disclosed with widespread applications as bio-medical sensors, vehicle status monitors and high-volume animal identification and health sensors. The sensor family allows measurement of temperatures, chemicals, acceleration and pressure. A microphone and clock realization is also available.

Strongly driven electron spins using a Ku band stripline electron paramagnetic resonance resonator

Science.gov (United States)

Yap, Yung Szen; Yamamoto, Hiroshi; Tabuchi, Yutaka; Negoro, Makoto; Kagawa, Akinori; Kitagawa, Masahiro

2013-07-01

This article details our work to obtain strong excitation for electron paramagnetic resonance (EPR) experiments by improving the resonator's efficiency. The advantages and application of strong excitation are discussed. Two 17 GHz transmission-type, stripline resonators were designed, simulated and fabricated. Scattering parameter measurements were carried out and quality factor were measured to be around 160 and 85. Simulation results of the microwave's magnetic field distribution are also presented. To determine the excitation field at the sample, nutation experiments were carried out and power dependence were measured using two organic samples at room temperature. The highest recorded Rabi frequency was rated at 210 MHz with an input power of about 1 W, which corresponds to a π/2 pulse of about 1.2 ns.

The [NeIV] Lines in High Excitation Gaseous Nebulae.

Science.gov (United States)

Aller, L H

1970-04-01

The "forbidden" lines of three times ionized neon are among the most precious indicators of electron temperature and excitation. They are also predicted to be among the strongest lines observed in the far ultraviolet spectra of high excitation nebulae.

Excitation of giant resonances via charge exchange reactions

International Nuclear Information System (INIS)

Goodman, C.D.

1979-01-01

Charge-exchange reactions can be useful for identifying isovector resonances. At present the most promising use of charge-exchange reactions with respect to giant resonances is to locate and study Gamow-Teller (GT) resonances. Detailed comparisons between GT and M1 strengths can yield further structure information. 7 figures

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

Predictions for Excited Strange Baryons

Energy Technology Data Exchange (ETDEWEB)

Fernando, Ishara P.; Goity, Jose L. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

2016-04-01

An assessment is made of predictions for excited hyperon masses which follow from flavor symmetry and consistency with a 1/N c expansion of QCD. Such predictions are based on presently established baryonic resonances. Low lying hyperon resonances which do not seem to fit into the proposed scheme are discussed.

Giant first-forbidden resonances

International Nuclear Information System (INIS)

Krmpotic, F.; Nakayama, K.; Sao Paulo Univ.; Pio Galeao, A.; Sao Paulo Univ.

1983-01-01

Recent experimental data on first-forbidden charge-exchange resonances are discussed in the framework of a schematic model. We also evaluate the screening of the weak coupling constants induced by both the giant resonances and the δ-isobar. It is shown that the last effect does not depend on the multipolarity of the one-particle moment. Due to the same reason, the fraction of the reaction strength pushed up into the δ-resonance region is always the same regardless of the quantum numbers carried by the excitation. Simple expressions are derived for the dependence of the excitation energies of the first-forbidden giant resonances on the mass number and isospin of the target. The model reproduces consistently both the Gamow-Teller and the first-forbidden resonances. (orig.)

vuv fluorescence from selective high-order multiphoton excitation of N2

International Nuclear Information System (INIS)

Coffee, Ryan N.; Gibson, George N.

2004-01-01

Recent fluorescence studies suggest that ultrashort pulse laser excitation may be highly selective. Selective high-intensity laser excitation holds important consequences for the physics of multiphoton processes. To establish the extent of this selectivity, we performed a detailed comparative study of the vacuum ultraviolet fluorescence resulting from the interaction of N 2 and Ar with high-intensity infrared ultrashort laser pulses. Both N 2 and Ar reveal two classes of transitions, inner-valence ns ' l ' . From their pressure dependence, we associate each transition with either plasma or direct laser excitation. Furthermore, we qualitatively confirm such associations with the time dependence of the fluorescence signal. Remarkably, only N 2 presents evidence of direct laser excitation. This direct excitation produces ionic nitrogen fragments with inner-valence (2s) holes, two unidentified transitions, and one molecular transition, the N 2 + :X 2 Σ g + 2 Σ u + . We discuss these results in the light of a recently proposed model for multiphoton excitation

Asymmetric excitation of surface plasmons by dark mode coupling

KAUST Repository

Zhang, X.

2016-02-19

Control over surface plasmons (SPs) is essential in a variety of cutting-edge applications, such as highly integrated photonic signal processing systems, deep-subwavelength lasing, high-resolution imaging, and ultrasensitive biomedical detection. Recently, asymmetric excitation of SPs has attracted enormous interest. In free space, the analog of electromagnetically induced transparency (EIT) in metamaterials has been widely investigated to uniquely manipulate the electromagnetic waves. In the near field, we show that the dark mode coupling mechanism of the classical EIT effect enables an exotic and straightforward excitation of SPs in a metasurface system. This leads to not only resonant excitation of asymmetric SPs but also controllable exotic SP focusing by the use of the Huygens-Fresnel principle. Our experimental findings manifest the potential of developing plasmonic metadevices with unique functionalities.

Asymmetric excitation of surface plasmons by dark mode coupling

KAUST Repository

Zhang, X.; Xu, Q.; Li, Q.; Xu, Y.; Gu, J.; Tian, Z.; Ouyang, C.; Liu, Y.; Zhang, S.; Zhang, Xixiang; Han, J.; Zhang, W.

2016-01-01

Control over surface plasmons (SPs) is essential in a variety of cutting-edge applications, such as highly integrated photonic signal processing systems, deep-subwavelength lasing, high-resolution imaging, and ultrasensitive biomedical detection. Recently, asymmetric excitation of SPs has attracted enormous interest. In free space, the analog of electromagnetically induced transparency (EIT) in metamaterials has been widely investigated to uniquely manipulate the electromagnetic waves. In the near field, we show that the dark mode coupling mechanism of the classical EIT effect enables an exotic and straightforward excitation of SPs in a metasurface system. This leads to not only resonant excitation of asymmetric SPs but also controllable exotic SP focusing by the use of the Huygens-Fresnel principle. Our experimental findings manifest the potential of developing plasmonic metadevices with unique functionalities.

Application of laser resonance scattering to the study of high-temperature plasma-wall interaction

International Nuclear Information System (INIS)

Maeda, Mitsuo; Muraoka, Katsunori; Hamamoto, Makoto; Akazaki, Masanori; Miyazoe, Yasushi

1981-01-01

Studies on laser resonance scattering and its application to the study of high-temperature plasma-wall interaction are reviewed. The application of dye laser beam to resonant scattering method has been developed. This method is able to detect low density atoms. The fluorescent photon counts can be estimated for a two-level system and a three-level system. The S/N ratio, Which is in close connection with the detection limit, has been estimated. The doppler effect due to the thermal motion of atoms is taken into consideration. The calibration of the absolute number of atoms is necessary. Tunable coherent light is used as the light source for resonance scattering method. This is able to excite atoms strongly and to increase the detection efficiency. As dye lasers, a N 2 laser, a YAG laser, and a KrF excimer laser have been studied. In VUV region, rare gas or rare gas halide lasers can be used. The strong output power can be expected when the resonance lines of atoms meet the synchronizing region of the excimer laser. The resonance scattering method is applied to the detection of impurity metal atoms in plasma. The studies of laser systems for the detection of hydrogen atoms are also in progress. (Kato, T.)

Excitation of graphene plasmons as an analogy with the two-level system

International Nuclear Information System (INIS)

Fu, Jiahui; Lv, Bo; Li, Rujiang; Ma, Ruyu; Chen, Wan; Meng, Fanyi

2016-01-01

The excitation of graphene plasmons (GPs) is presented as an interaction between the GPs and the incident electromagnetic field. In this Letter, the excitation of GPs in a plasmonic system is interpreted as an analogy with the two-level system by taking the two-coupled graphene-covered gratings as an example. Based on the equivalent circuit theory, the excitation of GPs in the graphene-covered grating is equivalent to the resonance of an oscillator. Thus, according to the governing equation, the electric currents at the resonant frequencies for two-coupled graphene-covered gratings correspond to the energy states in a two-level system. In addition, the excitation of GPs in different two-coupled graphene-covered gratings is numerically studied to validate our theoretical model. Our work provides an intuitive understanding of the excitation of GPs using an analogy with the two-level system. - Highlights: • The excitation of graphene plasmons (GPs) in graphene-covered grating is equivalent to the resonance of an oscillator. • We establish the equivalent circuit of two-level system to analyze the resonant character. • The excitation of GPs in different two-coupled graphene-covered gratings are numerically studied to validate our theoretical model.

Excitation of graphene plasmons as an analogy with the two-level system

Energy Technology Data Exchange (ETDEWEB)

Fu, Jiahui [Microwave and Electromagnetic Laboratory, Harbin Institute of Technology, No. 92, Xidazhi Street, Nangang District, Harbin City, Heilongjiang Province (China); Lv, Bo, E-mail: lb19840313@126.com [Microwave and Electromagnetic Laboratory, Harbin Institute of Technology, No. 92, Xidazhi Street, Nangang District, Harbin City, Heilongjiang Province (China); Li, Rujiang [College of Information Science and Electronic Engineering, Zhejiang University, Hangzhou 310027 (China); Ma, Ruyu; Chen, Wan; Meng, Fanyi [Microwave and Electromagnetic Laboratory, Harbin Institute of Technology, No. 92, Xidazhi Street, Nangang District, Harbin City, Heilongjiang Province (China)

2016-02-15

The excitation of graphene plasmons (GPs) is presented as an interaction between the GPs and the incident electromagnetic field. In this Letter, the excitation of GPs in a plasmonic system is interpreted as an analogy with the two-level system by taking the two-coupled graphene-covered gratings as an example. Based on the equivalent circuit theory, the excitation of GPs in the graphene-covered grating is equivalent to the resonance of an oscillator. Thus, according to the governing equation, the electric currents at the resonant frequencies for two-coupled graphene-covered gratings correspond to the energy states in a two-level system. In addition, the excitation of GPs in different two-coupled graphene-covered gratings is numerically studied to validate our theoretical model. Our work provides an intuitive understanding of the excitation of GPs using an analogy with the two-level system. - Highlights: • The excitation of graphene plasmons (GPs) in graphene-covered grating is equivalent to the resonance of an oscillator. • We establish the equivalent circuit of two-level system to analyze the resonant character. • The excitation of GPs in different two-coupled graphene-covered gratings are numerically studied to validate our theoretical model.

Nonlinear plasma waves excited near resonance

International Nuclear Information System (INIS)

Cohen, B.I.; Kaufman, A.N.

1977-01-01

The nonlinear resonant response of a uniform plasma to an external plane-wave field is formulated in terms of the mismatch Δ/sub n l/ between the driving frequency and the time-dependent, complex, nonlinear normal mode frequency at the driving wavenumber. This formalism is applied to computer simulations of this process, yielding a deduced nonlinear frequency shift. The time dependence of the nonlinear phenomena, at frequency Δ/sub n l/ and at the bounce frequency of the resonant particles, is analyzed. The interdependence of the nonlinear features is described by means of energy and momentum relations

Computer Simulations of Resonant Coherent Excitation of Heavy Hydrogen-Like Ions Under Planar Channeling

Science.gov (United States)

Babaev, A. A.; Pivovarov, Yu L.

2010-04-01

Resonant coherent excitation (RCE) of relativistic hydrogen-like ions is investigated by computer simulations methods. The suggested theoretical model is applied to the simulations of recent experiments on RCE of 390 MeV/u Ar17+ ions under (220) planar channeling in a Si crystal performed by T.Azuma et al at HIMAC (Tokyo). Theoretical results are in a good agreement with these experimental data and clearly show the appearance of the doublet structure of RCE peaks. The simulations are also extended to greater ion energies in order to predict the new RCE features at the future accelerator facility FAIR OSI and as an example, RCE of II GeV/u U91+ ions is considered in detail.

Effects of Resonant and Random Excitations on the Proton Beam in the Large Hadron Collider, with Applications to the Design of Pulsed Hollow Electron Lenses for Active Halo Control

Energy Technology Data Exchange (ETDEWEB)

Fitterer, Miriam; Stancari, Giulio; Valishev, Alexander; Redaelli, Stefano; Valuch, Daniel

2018-04-19

We present the results of numerical simulations and experimental studies about the effects of resonant and random excitations on proton losses, emittances, and beam distributions in the Large Hadron Collider (LHC). In addition to shedding light on complex nonlinear effects, these studies are applied to the design of hollow electron lenses (HEL) for active beam halo control. In the High-Luminosity Large Hadron Collider (HL-LHC), a considerable amount of energy will be stored in the beam tails. To control and clean the beam halo, the installation of two hollow electron lenses, one per beam, is being considered. In standard electron-lens operation, a proton bunch sees the same electron current at every revolution. Pulsed electron beam operation (i.e., different currents for different turns) is also considered, because it can widen the range of achievable halo removal rates. For an axially symmetric electron beam, only protons in the halo are excited. If a residual field is present at the location of the beam core, these particles are exposed to time-dependent transverse kicks and to noise. We discuss the numerical simulations and the experiments conducted in 2016 and 2017 at injection energy in the LHC. The excitation patterns were generated by the transverse feedback and damping system, which acted as a flexible source of dipole kicks. Proton beam losses, emittances, and transverse distributions were recorded as a function of excitation patterns and strengths. The resonant excitations induced rich dynamical effects and nontrivial changes of the beam distributions, which, to our knowledge, have not previously been observed and studied in this detail. We conclude with a discussion of the tolerable and achievable residual fields and proposals for further studies.

Study of the neutron decays of giant resonances excited by the inelastic scattering of 36 Ar on 90 Zr and 94 Zr targets at 44 MeV/u: a signature of multiphonon states

International Nuclear Information System (INIS)

Pascalon-Rozier, V.

1997-01-01

In inelastic heavy ion scattering, to angles near to the grazing angle, giant resonances (GR) are excited with very large differential cross sections. It has been shown that multiphonon states, states built with several GR quanta, can also been excited. These states can be revealed through the measurement of their decay by light particle emission. In this thesis, we report on the study of inelastic scattering of 36 Ar at 44 MeV/u on target of 90 Zr and 94 Zr, measured in coincidence with neutrons detected with the EDEN multidetector. The analysis of the inelastic spectra show evidence for a structure at high excitation energy, exhibiting characteristics compatible with a two-photon excitation. The construction of missing energy spectra allows us to the study of the GR and the high energy structure. In both nuclei, the GR presents a direct decay branch of 8%, which yields informations on the microscopic structure of the resonance. A two phonon state, interpreted as two weakly coupled GR's, built on one top of the other, and each phonon is expected to exhibit the same direct decay pattern as the GR. Such a simple decay is observed in the data, proving that the structure observed is due to the excitation of the two phonon state in both nuclei studied. Finally, we present a theoretical development based on Random Phase Approximation calculation, predicting that the two phonon state should be very harmonic. This result is in agreement with experimental studies of double phonon states over a large range of nuclei (from A = 12 to 208) carried out with several different probes. (author)

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)

Non-linear operation of nanomechnical systems combining photothermal excitation and magneto-motive detection

International Nuclear Information System (INIS)

Koenig, Daniel R; Metzger, Constanze; Camerer, Stephan; Kotthaus, Joerg P

2006-01-01

We present a non-linear operation of a nanomechanical beam resonator by photothermal excitation at 4 K. The resonators dimensions are 10 μm in length, 200 nm in width, and 200 nm in height. The actuation mechanism is based on a pulsed diode laser focused onto the centre of the beam resonator. Thermally induced stress caused by the different thermal expansion coefficients of the bi-layer system periodically deflects the resonator. Magnetomotively detected amplitudes up to 150 nm are reached at the fundamental resonance mode at a frequency of 8.9 MHz. Furthermore, the third eigenmode of the resonator at a frequency 36 MHz is also excited. We conclude that the photothermal excitation at 4 K should be applicable up to the GHz regime, the operation in the non-linear regime can be used for performance enhancement of nanomechanical systems, and the combination of photothermal excitation and magneto-motive detection avoids undesired cross talk

KLL resonant Auger transitions in metallic Cu and Ni

International Nuclear Information System (INIS)

Koever, L.; Berenyi, Z.; Cserny, I.

2004-01-01

Complete text of publication follows. KLL Auger spectra of 3d transition metals contain important information on the effects of the solid environment on deep core Auger transitions. Following the changes in the spectra when fine tuning the exciting photon energy across the K-shell ionization threshold with high energy resolution is informative concerning the possible resonant processes, expected to indicate the single-step nature of threshold Auger emission. The satellite structures in these spectra are strongly related to the unoccupied local electronic states above the Fermi level, as well as to the excitation, relaxation and screening processes associated with core hole ionization. In spite of the fundamental significance of the phenomena mentioned above, even non resonant high energy resolution studies of KLL Auger spectra of 3d transition metals (using laboratory X-ray sources) are very scarce due to the demanding experimental conditions requested. A very efficient tool for studying these phenomena is the Tunable High Energy XPS developed at HASYLAB which provides unique conditions, photon x and energy resolution for deep core Auger spectroscopy. Using the THE-XPS instrument at the BW2 beamline the high energy resolution (ΔE = 0.2 eV) KL 2,3 L 2,3 Auger spectra of polycrystalline Cu and Ni foils were measured with the Scienta SES-200 hemispherical analyzer. In the high energy range Cu 2p photo-electron peaks appearing in the Cu KLL Auger spectra due to the excitation by internal Cu K X-rays and trusted value for the Cu 2p3/2 binding energy were used for energy calibration. The exciting photon energy range was tuned up to about 50 eV above the K absorption edge and for the resonant energy region to 5 eV (Cu KLL) and 4 eV (Ni KLL) below threshold ensuring a photon beam with an energy width of about 1.1 eV. The evolution of the satellite structure as a function of excitation energy above threshold indicates di rent behaviour for particular satellites, making

Slotted cage resonator for high-field magnetic resonance imaging of rodents

Energy Technology Data Exchange (ETDEWEB)

Marrufo, O; Vasquez, F; Solis, S E; Rodriguez, A O, E-mail: arog@xanum.uam.mx [Departamento de Ingenieria Electrica, Universidad Autonoma Metropolitana Iztapalapa, Mexico, DF 09340 (Mexico)

2011-04-20

A variation of the high-frequency cavity resonator coil was experimentally developed according to the theoretical frame proposed by Mansfield in 1990. Circular slots were used instead of cavities to form the coil endplates and it was called the slotted cage resonator coil. The theoretical principles were validated via a coil equivalent circuit and also experimentally with a coil prototype. The radio frequency magnetic field, B1, produced by several coil configurations was numerically simulated using the finite-element approach to investigate their performances. A transceiver coil, 8 cm long and 7.6 cm in diameter, and composed of 4 circular slots with a 15 mm diameter on both endplates, was built to operate at 300 MHz and quadrature driven. Experimental results obtained with the slotted cage resonator coil were presented and showed very good agreement with the theoretical expectations for the resonant frequency as a function of the coil dimensions and slots. A standard birdcage coil was also built for performance comparison purposes. Phantom images were then acquired to compute the signal-to-noise ratio of both coils showing an important improvement of the slotted cage coil over the birdcage coil. The whole-body images of the mouse were also obtained showing high-quality images. Volume resonator coils can be reliably built following the physical principles of the cavity resonator design for high-field magnetic resonance imaging applications of rodents.

Highly Tunable Electrostatic Nanomechanical Resonators

KAUST Repository

Kazmi, Syed Naveed Riaz

2017-11-24

There has been significant interest towards highly tunable resonators for on-demand frequency selection in modern communication systems. Here, we report highly tunable electrostatically actuated silicon-based nanomechanical resonators. In-plane doubly-clamped bridges, slightly curved as shallow arches due to residual stresses, are fabricated using standard electron beam lithography and surface nanomachining. The resonators are designed such that the effect of mid-plane stretching dominates the softening effect of the electrostatic force. This is achieved by controlling the gap-to-thickness ratio and by exploiting the initial curvature of the structure from fabrication. We demonstrate considerable increase in the resonance frequency of nanoresonators with the dc bias voltages up to 108% for 180 nm thick structures with a transduction gap of 1 $mu$m separating them from the driving/sensing electrodes. The experimental results are found in good agreement with those of a nonlinear analytical model based on the Euler-Bernoulli beam theory. As a potential application, we demonstrate a tunable narrow band-pass filter using two electrically coupled nanomechanical arch resonators with varied dc bias voltages.

Highly Tunable Electrostatic Nanomechanical Resonators

KAUST Repository

Kazmi, Syed Naveed Riaz; Hajjaj, Amal Z.; Hafiz, Md Abdullah Al; Da Costa, Pedro M. F. J.; Younis, Mohammad I.

2017-01-01

There has been significant interest towards highly tunable resonators for on-demand frequency selection in modern communication systems. Here, we report highly tunable electrostatically actuated silicon-based nanomechanical resonators. In-plane doubly-clamped bridges, slightly curved as shallow arches due to residual stresses, are fabricated using standard electron beam lithography and surface nanomachining. The resonators are designed such that the effect of mid-plane stretching dominates the softening effect of the electrostatic force. This is achieved by controlling the gap-to-thickness ratio and by exploiting the initial curvature of the structure from fabrication. We demonstrate considerable increase in the resonance frequency of nanoresonators with the dc bias voltages up to 108% for 180 nm thick structures with a transduction gap of 1 $mu$m separating them from the driving/sensing electrodes. The experimental results are found in good agreement with those of a nonlinear analytical model based on the Euler-Bernoulli beam theory. As a potential application, we demonstrate a tunable narrow band-pass filter using two electrically coupled nanomechanical arch resonators with varied dc bias voltages.

Soliton-induced nonlocal resonances observed through high-intensity tunable spectrally compressed second-harmonic peaks

DEFF Research Database (Denmark)

Zhou, Binbin; Guo, Hairun; Bache, Morten

2014-01-01

Experimental data of femtosecond thick-crystal second-harmonic generation show that when tuning away from phase matching, a dominating narrow spectral peak appears in the second harmonic that can be tuned over hundreds of nanometers by changing the phase-mismatch parameter. Traditional theory...... and the nonlocal theory indirectly proves that we have observed a soliton-induced nonlocal resonance. The soliton exists in the self-defocusing regime of the cascaded nonlinear interaction and in the normal dispersion regime of the crystal, and needs high input intensities to become excited....

Resonance internal conversion as a way of accelerating nuclear processes

International Nuclear Information System (INIS)

Karpeshin, F.F.

2006-01-01

Theory of resonance conversion is presented. Being a natural extension of the traditional internal conversion into the subthreshold area, resonance conversion in a number of cases strongly affects the nuclear processes. Moreover, concentrating the transition strength on the narrow bands corresponding to the spectral atomic lines, it offers a unique tool capable of accelerating nuclear decay rates. Furthermore, along with the conventional nonradiative process of nuclear excitation through NEET and its reverse, TEEN, resonance conversion offers an appropriate mathematics for consideration of a number of cross-invariant processes involving both nuclei and electrons: excitation and deexcitation of the nuclei by hyperfine magnetic field, nuclear spin mixing, hyperfine interaction and magnetic anomalies in the atomic spectra, collisional nuclear excitation via ionization of the shells in the muon decay in the orbit, etc. The mechanisms of the optical pumping of the isomers are also considered, as well as triggering their energy in the resonance field of a laser. The effect is especially high in the hydrogen-like heavy ions due to practical absence of any damping of the resonance. The theory is also generalized to the case of the discrete Auger transitions [ru

Theoretical investigation of the hyper-Raman scattering in hexagonal semiconductors under two-photon excitation near resonance with the An=2 exciton level

Science.gov (United States)

Semenova, L. E.

2018-04-01

The hyper-Raman scattering of light by LO-phonons under two-photon excitation near resonance with the An=2 exciton level in the wurtzite semiconductors A2B6 was theoretically investigated, taking into account the influence of the complex structure of the top valence band.

Surface plasmon-enhanced two-photon excited whispering-gallery modes ultraviolet laser from Zno microwire

Directory of Open Access Journals (Sweden)

Yunpeng Wang

2017-11-01

Full Text Available The two-photon excited UV laser with narrow line width and high Q value was obtained. The total internal reflection from the four side surfaces of the quadrilateral-ZnO microwire offered the whispering gallery mode (WGM resonant cavity. The UV emission, resonant mechanism, and laser mode characteristics were discussed in detail for this special type of micro-cavity. In addition, in order to enhance the power of the two-photon excited UV laser, the surface plasmon enhancement by the Au nanoparticles was also performed and explained well by the theory of the localized surface plasmon.

Selective Two-Photon Absorptive Resonance Femtosecond-Laser Electronic-Excitation Tagging (STARFLEET) Velocimetry in Flow and Combustion Diagnostics

Science.gov (United States)

Jiang, Naibo; Halls, Benjamin R.; Stauffer, Hans U.; Roy, Sukesh; Danehy, Paul M.; Gord, James R.

2016-01-01

Selective Two-Photon Absorptive Resonance Femtosecond-Laser Electronic-Excitation Tagging (STARFLEET), a non-seeded ultrafast-laser-based velocimetry technique, is demonstrated in reactive and non-reactive flows. STARFLEET is pumped via a two-photon resonance in N2 using 202.25-nm 100-fs light. STARFLEET greatly reduces the per-pulse energy required (30 µJ/pulse) to generate the signature FLEET emission compared to the conventional FLEET technique (1.1 mJ/pulse). This reduction in laser energy results in less energy deposited in the flow, which allows for reduced flow perturbations (reactive and non-reactive), increased thermometric accuracy, and less severe damage to materials. Velocity measurements conducted in a free jet of N2 and in a premixed flame show good agreement with theoretical velocities and further demonstrate the significantly less-intrusive nature of STARFLEET.

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

High-frequency domain wall excitations in magnetic garnet films with in-plane magnetization

International Nuclear Information System (INIS)

Synogach, V.T.; Doetsch, H.

1996-01-01

Magnetic garnet films of compositions (YBi) 3 Fe 5 O 12 and (LuBi) 3 Fe 5 O 12 are grown by liquid-phase epitaxy on [110]- and [100]-oriented substrates of gadolinium gallium garnet, respectively. All films have in-plane magnetization. 180 degree and 90 degree domain walls in these films are studied by microwave technique. In addition to the known low-frequency mode of wall translation new multiple resonant modes of both 90 degree and 180 degree domain walls with very small linewidth (4.2 MHz) are observed at frequencies near 1 GHz. Resonances are effectively excited by an rf magnetic field which is parallel or perpendicular to the wall plane. Resonance frequencies are shown to have nonlinear dispersion dependence on the mode number: they decrease with increasing in-plane magnetic field normal to the wall plane. copyright 1996 The American Physical Society

Laser excitation of 8-eV electronic states in Th{sup +}. A first pillar of the electronic bridge toward excitation of the Th-229 nucleus

Energy Technology Data Exchange (ETDEWEB)

Herrera-Sancho, Oscar-Andrey

2012-11-23

The possibility to realize a nuclear clock based on the optical magnetic dipole transition from the ground state to the low-energy isomeric state in the {sup 229}Th nucleus has motivated experiments and proposals toward highly accurate clocks with trapped ions and highly stable optical frequency standards with Th-doped solids. These systems hold great promise to open a field of research in the borderland between atomic and nuclear physics, which will enable highly sensitive tests of postulates from fundamental physics and also will allow us to coherently excite and control nuclear states, opening a wonderful and intriguing new field in physics. A major experimental obstacle that has to be overcome before any precision spectroscopy can be performed with this system is however the insufficient knowledge on the exact transition energy. The best experimental result so far is an indirect determination from {gamma}-spectroscopy with a relative uncertainty of about 6%. To facilitate the search for the nuclear transition within a wide uncertainty range around 8 eV, we investigate two-photon excitation in the dense electronic level structure of Th{sup +}, which enables the nuclear excitation via a resonantly enhanced inverse electronic bridge process. Experiments on one- and two-photon laser excitation of buffer gas cooled {sup 232}Th{sup +} ions in a radio-frequency ion trap are reported in this thesis. The strongest resonance line at 402 nm from the (6d{sup 2}7s)J=3/2 ground state to the (6d7s7p)J=5/2 state is driven as the first excitation step. Using nanosecond laser pulses in the 250-nm wavelength range for the second step of a two-photon excitation, we have observed seven previously unknown levels in the unexplored region of the electronic level structure around 8 eV. This investigation shows that the Th{sup +} ion seems to be well suited for the search of the isomer transition because both, theory and experimental results, agree on the density of strong transitions

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.

Parametric resonance in superconducting micron-scale waveguides

International Nuclear Information System (INIS)

Fomin, N.V.; Shalaev, O.L.; Shantsev, D.V.

1997-01-01

A parametric resonance due to temperature oscillations in superconducting micron-scale waveguides is considered. Oscillations of superconductor temperature are assumed to be induced by the irradiation of the waveguide with a laser beam. The laser power and parameters of the waveguide providing a possibility of parametric excitation have been calculated. It is shown that for a waveguide made of a YBa 2 Cu 3 O 7 microstrip with resonant frequency of 10 GHz a laser with a power of about 70 W/cm 2 is needed to excite oscillations. The effect can be used for the creation of high-sensitivity tuneable filters and optoelectric transformers on superconducting microstrips in the GHz range. copyright 1997 American Institute of Physics

Excitation of nonaxisymmetric perturbations by the axisymmetric explosive magnetorotational instability in Keplerian discs

Science.gov (United States)

Shtemler, Yu.; Mond, M.; Liverts, E.

2018-02-01

The excitation of nonaxisymmetric quasi-resonant triads by clustering around a dominant axisymmetric explosively unstable magnetorotational instability (MRI) in Keplerian discs is investigated. Clustering, namely, the mutual interactions of a large number of quasi-resonant triads that are connected by a single dominant explosively unstable axisymmetric triad, is invoked in order to provide a viable mechanism for the stabilization of the explosive nature of the latter. The results, however, are of wider scope as the proposed clustering scenario also provides a strong mechanism for the excitation of high-amplitude nonaxisymmetric perturbations. The latter play a major role in the nonlinear evolution of the MRI on the route to fully developed turbulence.

Extremely confined gap surface-plasmon modes excited by electrons

DEFF Research Database (Denmark)

Raza, Søren; Stenger, Nicolas; Pors, Anders Lambertus

2014-01-01

High-spatial and energy resolution electron energy-loss spectroscopy (EELS) can be used for detailed characterization of localized and propagating surface-plasmon excitations in metal nanostructures, giving insight into fundamental physical phenomena and various plasmonic effects. Here, applying...... EELS to ultra-sharp convex grooves in gold, we directly probe extremely confined gap surface-plasmon (GSP) modes excited by swift electrons in nanometre-wide gaps. We reveal the resonance behaviour associated with the excitation of the antisymmetric GSP mode for extremely small gap widths, down to ~5...... mode exploited in plasmonic waveguides with extreme light confinement is a very important factor that should be taken into account in the design of nanoplasmonic circuits and devices....

Improved ion acceleration via laser surface plasma waves excitation

Energy Technology Data Exchange (ETDEWEB)

Bigongiari, A. [CEA/DSM/LSI, CNRS, Ecole Polytechnique, 91128 Palaiseau Cedex (France); TIPS/LULI, Université Paris 6, CNRS, CEA, Ecole Polytechnique, 3, rue Galilée, 94200 Ivry-sur-Seine (France); Raynaud, M. [CEA/DSM/LSI, CNRS, Ecole Polytechnique, 91128 Palaiseau Cedex (France); Riconda, C. [TIPS/LULI, Université Paris 6, CNRS, CEA, Ecole Polytechnique, 3, rue Galilée, 94200 Ivry-sur-Seine (France); Héron, A. [CPHT, CNRS, Ecole Polytechnique, 91128 Palaiseau Cedex (France)

2013-05-15

The possibility of enhancing the emission of the ions accelerated in the interaction of a high intensity ultra-short (<100 fs) laser pulse with a thin target (<10λ{sub 0}), via surface plasma wave excitation is investigated. Two-dimensional particle-in-cell simulations are performed for laser intensities ranging from 10{sup 19} to 10{sup 20} Wcm{sup −2}μm{sup 2}. The surface wave is resonantly excited by the laser via the coupling with a modulation at the target surface. In the cases where the surface wave is excited, we find an enhancement of the maximum ion energy of a factor ∼2 compared to the cases where the target surface is flat.

11th Workshop on The Physics of Excited Nucleons

CERN Document Server

Hammer, Hans-Werner; Thoma, Ulrike; Schmieden, Hartmut; NSTAR 2007

2008-01-01

The excitation spectrum of the nucleon promises to offer important insights into the non-perturbative regime of QCD. Dedicated experimental programs at various laboratories exist to perform accurate measurements of meson photo- and electroproduction off the nucleon, studying its excitation. The NStar workshops are a well-established series of meetings that bring together experimenters and theoreticians working on baryon resonances and related areas to discuss New results on pseudoscalar and vector meson production; Partial wave analysis and resonance parameters; Baryon resonance structure and quark models; Dynamical models and coupled channel analysis; Baryon resonances in lattice QCD; Chiral symmetry and baryon resonances; Laboratory reports and future projects. The refereed and edited proceedings constitute an indispensable archival record of the progress in the field.

Collective 0+, 1+ and 2+ excitations in rotating nuclei

International Nuclear Information System (INIS)

Balbutsev, E.B.; Piperova, J.

1988-01-01

The energies and B(Eγ) factors of the isoscalar and isovector 0 + and 2 + resonances are calculated with Skyrme interaction. A satisfactory agreement with experimental data is obtained. It is shown that in rotating nuclei the 2 + excitations split into five branches and also 5 low-lying excitations appear. Two of these low-lying modes are angular resonances and the theory reproduces their energies and B(M1) factors. The experimentally observed splitting of giant monopole resonance in deformed nuclei is confirmed. 34 refs.; 10 figs.; 1 tab

Nucleon Resonance Physics

Energy Technology Data Exchange (ETDEWEB)

Burkert, Volker D.

2016-07-25

Recent results of meson photo-production at the existing electron machines with polarized real photon beams and the measurement of polarization observables of the final state baryons have provided high precision data that led to the discovery of new excited nucleon and $\\Delta$ states using multi-channel partial wave analyses procedures. The internal structure of several prominent excited states has been revealed employing meson electroproduction processes. On the theoretical front, lattice QCD is now predicting the baryon spectrum with very similar characteristics as the constituent quark model, and continuum QCD, such as is represented in the Dyson-Schwinger Equations approach and in light front relativistic quark models, describes the non-perturbative behavior of resonance excitations at photon virtuality of $Q^2 > 1.5GeV^2$. In this talk I discuss the need to continue a vigorous program of nucleon spectroscopy and the study of the internal structure of excited states as a way to reveal the effective degrees of freedom underlying the excited states and their dependence on the distance scale probed.

Strong Coupling Cavity QED with Gate-Defined Double Quantum Dots Enabled by a High Impedance Resonator

Directory of Open Access Journals (Sweden)

A. Stockklauser

2017-03-01

Full Text Available The strong coupling limit of cavity quantum electrodynamics (QED implies the capability of a matterlike quantum system to coherently transform an individual excitation into a single photon within a resonant structure. This not only enables essential processes required for quantum information processing but also allows for fundamental studies of matter-light interaction. In this work, we demonstrate strong coupling between the charge degree of freedom in a gate-defined GaAs double quantum dot (DQD and a frequency-tunable high impedance resonator realized using an array of superconducting quantum interference devices. In the resonant regime, we resolve the vacuum Rabi mode splitting of size 2g/2π=238  MHz at a resonator linewidth κ/2π=12  MHz and a DQD charge qubit decoherence rate of γ_{2}/2π=40  MHz extracted independently from microwave spectroscopy in the dispersive regime. Our measurements indicate a viable path towards using circuit-based cavity QED for quantum information processing in semiconductor nanostructures.

Measurement of resonance parameters of orbitally excited narrow B0 mesons.

Science.gov (United States)

Aaltonen, T; Adelman, J; Akimoto, T; Albrow, M G; González, B Alvarez; Amerio, S; Amidei, D; Anastassov, A; Annovi, A; Antos, J; Apollinari, G; Apresyan, A; Arisawa, T; Artikov, A; Ashmanskas, W; Attal, A; Aurisano, A; Azfar, F; Azzurri, P; Badgett, W; Barbaro-Galtieri, A; Barnes, V E; Barnett, B A; Bartsch, V; Bauer, G; Beauchemin, P-H; Bedeschi, F; Beecher, D; Behari, S; Bellettini, G; Bellinger, J; Benjamin, D; Beretvas, A; Beringer, J; Bhatti, A; Binkley, M; Bisello, D; Bizjak, I; Blair, R E; Blocker, C; Blumenfeld, B; Bocci, A; Bodek, A; Boisvert, V; Bolla, G; Bortoletto, D; Boudreau, J; Boveia, A; Brau, B; Bridgeman, A; Brigliadori, L; Bromberg, C; Brubaker, E; Budagov, J; Budd, H S; Budd, S; Burke, S; Burkett, K; Busetto, G; Bussey, P; Buzatu, A; Byrum, K L; Cabrera, S; Calancha, C; Campanelli, M; Campbell, M; Canelli, F; Canepa, A; Carls, B; Carlsmith, D; Carosi, R; Carrillo, S; Carron, S; Casal, B; Casarsa, M; Castro, A; Catastini, P; Cauz, D; Cavaliere, V; Cavalli-Sforza, M; Cerri, A; Cerrito, L; Chang, S H; Chen, Y C; Chertok, M; Chiarelli, G; Chlachidze, G; Chlebana, F; Cho, K; Chokheli, D; Chou, J P; Choudalakis, G; Chuang, S H; Chung, K; Chung, W H; Chung, Y S; Chwalek, T; Ciobanu, C I; Ciocci, M A; Clark, A; Clark, D; Compostella, G; Convery, M E; Conway, J; Cordelli, M; Cortiana, G; Cox, C A; Cox, D J; Crescioli, F; Almenar, C Cuenca; Cuevas, J; Culbertson, R; Cully, J C; Dagenhart, D; Datta, M; Davies, T; de Barbaro, P; De Cecco, S; Deisher, A; De Lorenzo, G; Dell'orso, M; Deluca, C; Demortier, L; Deng, J; Deninno, M; Derwent, P F; di Giovanni, G P; Dionisi, C; Di Ruzza, B; Dittmann, J R; D'Onofrio, M; Donati, S; Dong, P; Donini, J; Dorigo, T; Dube, S; Efron, J; Elagin, A; Erbacher, R; Errede, D; Errede, S; Eusebi, R; Fang, H C; Farrington, S; Fedorko, W T; Feild, R G; Feindt, M; Fernandez, J P; Ferrazza, C; Field, R; Flanagan, G; Forrest, R; Frank, M J; Franklin, M; Freeman, J C; Furic, I; Gallinaro, M; Galyardt, J; Garberson, F; Garcia, J E; Garfinkel, A F; Genser, K; Gerberich, H; Gerdes, D; Gessler, A; Giagu, S; Giakoumopoulou, V; Giannetti, P; Gibson, K; Gimmell, J L; Ginsburg, C M; Giokaris, N; Giordani, M; Giromini, P; Giunta, M; Giurgiu, G; Glagolev, V; Glenzinski, D; Gold, M; Goldschmidt, N; Golossanov, A; Gomez, G; Gomez-Ceballos, G; Goncharov, M; González, O; Gorelov, I; Goshaw, A T; Goulianos, K; Gresele, A; Grinstein, S; Grosso-Pilcher, C; Grundler, U; da Costa, J Guimaraes; Gunay-Unalan, Z; Haber, C; Hahn, K; Hahn, S R; Halkiadakis, E; Han, B-Y; Han, J Y; Happacher, F; Hara, K; Hare, D; Hare, M; Harper, S; Harr, R F; Harris, R M; Hartz, M; Hatakeyama, K; Hays, C; Heck, M; Heijboer, A; Heinrich, J; Henderson, C; Herndon, M; Heuser, J; Hewamanage, S; Hidas, D; Hill, C S; Hirschbuehl, D; Hocker, A; Hou, S; Houlden, M; Hsu, S-C; Huffman, B T; Hughes, R E; Husemann, U; Huston, J; Incandela, J; Introzzi, G; Iori, M; Ivanov, A; James, E; Jayatilaka, B; Jeon, E J; Jha, M K; Jindariani, S; Johnson, W; Jones, M; Joo, K K; Jun, S Y; Jung, J E; Junk, T R; Kamon, T; Kar, D; Karchin, P E; Kato, Y; Kephart, R; Keung, J; Khotilovich, V; Kilminster, B; Kim, D H; Kim, H S; Kim, H W; Kim, J E; Kim, M J; Kim, S B; Kim, S H; Kim, Y K; Kimura, N; Kirsch, L; Klimenko, S; Knuteson, B; Ko, B R; Kondo, K; Kong, D J; Konigsberg, J; Korytov, A; Kotwal, A V; Kreps, M; Kroll, J; Krop, D; Krumnack, N; Kruse, M; Krutelyov, V; Kubo, T; Kuhr, T; Kulkarni, N P; Kurata, M; Kusakabe, Y; Kwang, S; Laasanen, A T; Lami, S; Lammel, S; Lancaster, M; Lander, R L; Lannon, K; Lath, A; Latino, G; Lazzizzera, I; Lecompte, T; Lee, E; Lee, H S; Lee, S W; Leone, S; Lewis, J D; Lin, C-S; Linacre, J; Lindgren, M; Lipeles, E; Lister, A; Litvintsev, D O; Liu, C; Liu, T; Lockyer, N S; Loginov, A; Loreti, M; Lovas, L; Lucchesi, D; Luci, C; Lueck, J; Lujan, P; Lukens, P; Lungu, G; Lyons, L; Lys, J; Lysak, R; Macqueen, D; Madrak, R; Maeshima, K; Makhoul, K; Maki, T; Maksimovic, P; Malde, S; Malik, S; Manca, G; Manousakis-Katsikakis, A; Margaroli, F; Marino, C; Marino, C P; Martin, A; Martin, V; Martínez, M; Martínez-Ballarín, R; Maruyama, T; Mastrandrea, P; Masubuchi, T; Mathis, M; Mattson, M E; Mazzanti, P; McFarland, K S; McIntyre, P; McNulty, R; Mehta, A; Mehtala, P; Menzione, A; Merkel, P; Mesropian, C; Miao, T; Miladinovic, N; Miller, R; Mills, C; Milnik, M; Mitra, A; Mitselmakher, G; Miyake, H; Moggi, N; Moon, C S; Moore, R; Morello, M J; Morlok, J; Fernandez, P Movilla; Mülmenstädt, J; Mukherjee, A; Muller, Th; Mumford, R; Murat, P; Mussini, M; Nachtman, J; Nagai, Y; Nagano, A; Naganoma, J; Nakamura, K; Nakano, I; Napier, A; Necula, V; Nett, J; Neu, C; Neubauer, M S; Neubauer, S; Nielsen, J; Nodulman, L; Norman, M; Norniella, O; Nurse, E; Oakes, L; Oh, S H; Oh, Y D; Oksuzian, I; Okusawa, T; Orava, R; Griso, S Pagan; Palencia, E; Papadimitriou, V; Papaikonomou, A; Paramonov, A A; Parks, B; Pashapour, S; Patrick, J; Pauletta, G; Paulini, M; Paus, C; Peiffer, T; Pellett, D E; Penzo, A; Phillips, T J; Piacentino, G; Pianori, E; Pinera, L; Pitts, K; Plager, C; Pondrom, L; Poukhov, O; Pounder, N; Prakoshyn, F; Pronko, A; Proudfoot, J; Ptohos, F; Pueschel, E; Punzi, G; Pursley, J; Rademacker, J; Rahaman, A; Ramakrishnan, V; Ranjan, N; Redondo, I; Rekovic, V; Renton, P; Renz, M; Rescigno, M; Richter, S; Rimondi, F; Ristori, L; Robson, A; Rodrigo, T; Rodriguez, T; Rogers, E; Rolli, S; Roser, R; Rossi, M; Rossin, R; Roy, P; Ruiz, A; Russ, J; Rusu, V; Safonov, A; Sakumoto, W K; Saltó, O; Santi, L; Sarkar, S; Sartori, L; Sato, K; Savoy-Navarro, A; Schlabach, P; Schmidt, A; Schmidt, E E; Schmidt, M A; Schmidt, M P; Schmitt, M; Schwarz, T; Scodellaro, L; Scribano, A; Scuri, F; Sedov, A; Seidel, S; Seiya, Y; Semenov, A; Sexton-Kennedy, L; Sforza, F; Sfyrla, A; Shalhout, S Z; Shears, T; Shepard, P F; Shimojima, M; Shiraishi, S; Shochet, M; Shon, Y; Shreyber, I; Sidoti, A; Sinervo, P; Sisakyan, A; Slaughter, A J; Slaunwhite, J; Sliwa, K; Smith, J R; Snider, F D; Snihur, R; Soha, A; Somalwar, S; Sorin, V; Spalding, J; Spreitzer, T; Squillacioti, P; Stanitzki, M; St Denis, R; Stelzer, B; Stelzer-Chilton, O; Stentz, D; Strologas, J; Strycker, G L; Stuart, D; Suh, J S; Sukhanov, A; Suslov, I; Suzuki, T; Taffard, A; Takashima, R; Takeuchi, Y; Tanaka, R; Tecchio, M; Teng, P K; Terashi, K; Thom, J; Thompson, A S; Thompson, G A; Thomson, E; Tipton, P; Ttito-Guzmán, P; Tkaczyk, S; Toback, D; Tokar, S; Tollefson, K; Tomura, T; Tonelli, D; Torre, S; Torretta, D; Totaro, P; Tourneur, S; Trovato, M; Tsai, S-Y; Tu, Y; Turini, N; Ukegawa, F; Vallecorsa, S; van Remortel, N; Varganov, A; Vataga, E; Vázquez, F; Velev, G; Vellidis, C; Veszpremi, V; Vidal, M; Vidal, R; Vila, I; Vilar, R; Vine, T; Vogel, M; Volobouev, I; Volpi, G; Wagner, P; Wagner, R G; Wagner, R L; Wagner, W; Wagner-Kuhr, J; Wakisaka, T; Wallny, R; Wang, S M; Warburton, A; Waters, D; Weinberger, M; Weinelt, J; Wester, W C; Whitehouse, B; Whiteson, D; Wicklund, A B; Wicklund, E; Wilbur, S; Williams, G; Williams, H H; Wilson, P; Winer, B L; Wittich, P; Wolbers, S; Wolfe, C; Wright, T; Wu, X; Würthwein, F; Wynne, S M; Xie, S; Yagil, A; Yamamoto, K; Yamaoka, J; Yang, U K; Yang, Y C; Yao, W M; Yeh, G P; Yoh, J; Yorita, K; Yoshida, T; Yu, G B; Yu, I; Yu, S S; Yun, J C; Zanello, L; Zanetti, A; Zhang, X; Zheng, Y; Zucchelli, S

2009-03-13

We report a measurement of resonance parameters of the orbitally excited (L=1) narrow B0 mesons in decays to B;{(*)+}pi;{-} using 1.7 fb;{-1} of data collected by the CDF II detector at the Fermilab Tevatron. The mass and width of the B_{2};{*0} state are measured to be m(B_{2};{*0})=5740.2_{-1.8};{+1.7}(stat)-0.8+0.9(syst) MeV/c;{2} and Gamma(B_{2};{*0})=22.7_{-3.2};{+3.8}(stat)-10.2+3.2(syst) MeV/c;{2}. The mass difference between the B_{2};{*0} and B10 states is measured to be 14.9_{-2.5};{+2.2}(stat)-1.4+1.2(syst) MeV/c;{2}, resulting in a B10 mass of 5725.3_{-2.2};{+1.6}(stat)-1.5+1.4(syst) MeV/c;{2}. This is currently the most precise measurement of the masses of these states and the first measurement of the B_{2};{*0} width.

Two-photon excitation of argon

International Nuclear Information System (INIS)

Pindzola, P.S.; Payne, M.C.

1982-01-01

The authors calculate two photon excitation parameters for various excited states of argon assuming the absorption of near resonance broad-bandwidth laser radiation. Results are given for the case of two photons absorbed for the same laser beam as well as the case of absorbing photons of different frequency from each of two laser beams. The authors use multiconfiguration Hartree-Fock wave functions to evaluate the second-order sums over matrix elements. Various experimental laser schemes are suggested for the efficient excitation and subsequent ionization of argon

Two qubits in pure nuclear quadrupole resonance

International Nuclear Information System (INIS)

Furman, G.B.; Goren, S.D.; Meerovich, V.M.; Sokolovsky, V.L.

2002-01-01

It is shown theoretically that by the use of two radio-frequency fields of the same resonance frequency but with the different phases and directions the degeneracy of the energy spectrum of a spin system with I=3/2 is removed. This leads to four non-degenerate spin states which can be used as a platform for quantum computing. The feasibility of quantum computing based on a pure (without DC magnetic fields) nuclear quadrupole resonance technique is investigated in detail. Various quantum logic gates can be constructed by using different excitation techniques allowing different manipulations with the spin system states. Three realizations of quantum logic gates are considered: the application of an additional magnetic field with the resonance frequency, the amplitude modulation of one of the applied RF fields by the resonance frequency field, and the level-crossing method. It is shown that the probabilities of the resonance transitions depend on the method of excitation and on the direction of the excitation field. Feasibility of quantum computing is demonstrated with the examples of constructing a controlled-NOT logic gate using the resonance excitation technique and SWAP and NOT2 logic gates using the level-crossing method. (author)

Theoretical description of high-lying two-electrons states

International Nuclear Information System (INIS)

Greene, C.H.; Cavagnero, M.; Sadeghpour, H.R.

1993-01-01

Within the past two years, experiments on high-lying doubly-excited states in He and H- have shown spectra at energies near excited hydrogenic thresholds having principal quantum numbers in the range N=5--9. While they display some nontrivial complexities, the spectra are tremendously simpler than might be anticipated on the basis of independent electron models, in that only a small fraction of the total number of anticipated resonances are observed experimentally. Moreover, for principal quantum number N that are not too high, specifically N - , the resonance positions are described accurately by adiabatic calculations using hyperspherical coordinates and can be parametrized by a remarkably simple two-electron Rydberg formula. The observed propensity for excitation of only a small subset of the possible resonance states has been codified by several groups into approximate selection rules based on alternative (but apparently equivalent) classification schemes. Comparatively few attempts have been made at quantitative tests of the validity of these rules. The present review describes recent efforts to quantify their accuracy and limitations using R-matrix and quantum defect techniques, and Smith's delay-time matrix. Prospensity rules for exciting different degrees of freedom are found to differ greatly in their degree of validity

Consideration on excitation mechanisms in a high-power two-jet plasma

International Nuclear Information System (INIS)

Zaksas, Natalia P.; Gerasimov, Vladimir A.

2013-01-01

The study of excitation mechanisms in the region before the jet confluence of a high-power two-jet plasma used for analysis of different powders has been undertaken. Distribution of excited levels of Fe atoms and ions according to the Boltzmann population was found. Measuring Fe atomic and ionic excitation temperatures showed their considerable difference (≈ 2000–2500 K). The effect of argon on line intensities of a wide range of elements was investigated by the experiment with argon covering. A negligible effect of argon covering on line intensities of atoms with ionization energy of 8 eV was revealed. This is likely to be due to Penning ionization by metastable argon followed by ion recombination with an electron and stepwise de-excitations. A more pronounced effect of argon covering was observed for ionic lines of investigated elements with total excitation energy ranging from 11 to 21 eV. Penning ionization followed by electron impact is believed to be a probable mechanism for ion excitation. The contribution of metastable argon to excitation processes results in departure from local thermodynamic equilibrium and different atomic and ionic excitation temperatures. - Highlights: • Excitation mechanisms were investigated in a high-power TJP. • Boltzmann population of excited levels of Fe atoms and ions takes place. • The considerable difference in Fe atomic and ionic excitation temperatures occurs. • Argon covering was used to study the argon effect on line intensities. • Participation of metastable argon in atom ionization was shown

"Cul-de-sac" microstrip resonators for high-speed integrated optical commutator switches

Science.gov (United States)

Jaeger, Nicolas A.; Chen, Mingche

1993-04-01

A novel microstrip resonator structure for use with integrated Y-branch optical modulators fabricated in Ti:LiNbO3 is proposed. The legs of the structure are intended to act as the electrodes of the modulator, with light being directed into each of the output waveguides of the Y-branch on alternate half-cycles of the standing wave excited in the resonator; forming an optical commutator switch. Such resonators having Al2O3 substrates were designed, fabricated, and tested. Measurements on one such resonator, operating at 7.12 GHz and having an unloaded quality factor of 123, indicating that 50 V should develop across the ends of its legs for 35 mW dissipated power; the corresponding values, from the model used to design the resonator, were 179, 50 V,and 24 mW, respectively. Using the model it is shown that a similar resonator fabricated on LiNbO3 should be able to develop about 50 V for 100 mW dissipated power at 15 GHz.

MOSFET-based high voltage short pulse generator for ultrasonic transducer excitation

Science.gov (United States)

Hidayat, Darmawan; Setianto, Syafei, Nendi Suhendi; Wibawa, Bambang Mukti

2018-02-01

This paper presents the generation of a high-voltage short pulse for the excitation of high frequency ultrasonic transducers. This is highly required in the purpose of various ultrasonic-based evaluations, particularly when high resolution measurement is necessary. A high voltage (+760 V) DC voltage source was pulsated by an ultrafast switching MOSFET which was driven by a pulse generator circuit consisting of an astable multivibrator, a one-shot multivibrator with Schmitt trigger input and a high current MOSFET driver. The generated pulses excited a 200-kHz and a 1-MHz ultrasonic transducers and tested in the transmission mode propagation to evaluate the performances of the generated pulse. The test results showed the generator were able to produce negative spike pulses up to -760 V voltage with the shortest time-width of 107.1 nanosecond. The transmission-received ultrasonic waves show frequency oscillation at 200 and 961 kHz and their amplitudes varied with the voltage of excitation pulse. These results conclude that the developed pulse generator is applicable to excite transducer for the generation of high frequency ultrasonic waves.

Extreme secular excitation of eccentricity inside mean motion resonance. Small bodies driven into star-grazing orbits by planetary perturbations

Science.gov (United States)

Pichierri, Gabriele; Morbidelli, Alessandro; Lai, Dong

2017-09-01

Context. It is well known that asteroids and comets fall into the Sun. Metal pollution of white dwarfs and transient spectroscopic signatures of young stars like β-Pic provide growing evidence that extra solar planetesimals can attain extreme orbital eccentricities and fall into their parent stars. Aims: We aim to develop a general, implementable, semi-analytical theory of secular eccentricity excitation of small bodies (planetesimals) in mean motion resonances with an eccentric planet valid for arbitrary values of the eccentricities and including the short-range force due to General Relativity. Methods: Our semi-analytic model for the restricted planar three-body problem does not make use of series expansion and therefore is valid for any eccentricity value and semi-major axis ratio. The model is based on the application of the adiabatic principle, which is valid when the precession period of the longitude of pericentre of the planetesimal is much longer than the libration period in the mean motion resonance. In resonances of order larger than 1 this is true except for vanishingly small eccentricities. We provide prospective users with a Mathematica notebook with implementation of the model allowing direct use. Results: We confirm that the 4:1 mean motion resonance with a moderately eccentric (e' ≲ 0.1) planet is the most powerful one to lift the eccentricity of planetesimals from nearly circular orbits to star-grazing ones. However, if the planet is too eccentric, we find that this resonance is unable to pump the planetesimal's eccentricity to a very high value. The inclusion of the General Relativity effect imposes a condition on the mass of the planet to drive the planetesimals into star-grazing orbits. For a planetesimal at 1 AU around a solar mass star (or white dwarf), we find a threshold planetary mass of about 17 Earth masses. We finally derive an analytical formula for this critical mass. Conclusions: Planetesimals can easily fall into the central star

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

Theory of nuclear excitation by electron capture for heavy ions

Energy Technology Data Exchange (ETDEWEB)

Gagyi-Palffy, A.

2006-07-01

The resonant process of nuclear excitation by electron capture (NEEC) in collisions involving highly-charged ions has been investigated theoretically. NEEC is a rare recombination process in which a free electron is captured into a bound shell of an ion with the simultaneous excitation of the nucleus. Total cross sections for NEEC followed by the radiative decay of the excited nucleus are presented for various collision systems. The possibility to observe the NEEC in scattering experiments with trapped or stored ions was discussed focusing on the cases with the largest calculated resonance strength. As the photons emitted in different channels of the electron recombination process are indistinguishable in the total cross section, the interference between NEEC followed by the radiative decay of the nucleus and radiative recombination was investigated. The angular distribution of the emitted photons in the recombination process provides means to discern the two processes. Angular differential cross sections for the emitted photons in the case of E2 nuclear transitions were presented for several heavy elements. (orig.)

Giant resonances in heavy-ion reactions

International Nuclear Information System (INIS)

Hussein, M.S.

1982-11-01

The several roles of multipole giant resonances in heavy-ion reactions are discussed. In particular, the modifications in the effective ion-ion potencial due to the virtual excitation of giant resonances at low energies, are considered and estimated for several systems. Real excitation of giant resonances in heavy-ion reactions at intermediate energies are then discussed and their importance in the approach phase of deeply inelastic processes in emphasized. Several demonstrative examples are given. (Author) [pt

Dynamic behavior of three-dimensional composite beam under flapwise excitation

Energy Technology Data Exchange (ETDEWEB)

Eftekhari, Mojtaba [Dept. of Mechanical Engineering, Shahid Bahonar University of Kerman, Kerman (Iran, Islamic Republic of)

2016-08-15

In this paper, dynamic response of a symmetrically laminated composite beam is studied under harmonic base excitation. The base is subjected to flapwise excitation tuned to the primary resonance in the presence of 2:1 internal resonance between the out-of-plane bending motion and the in-plane bending and torsional motions. In literature, modified modulation equations of composite beam have been derived and the stability of fixed points has been investigated in frequency and forced responses. However, post-critical behavior of the modulation equations is studied in this study. In bifurcation diagrams sketched near primary and internal resonances, it appears that detuning the flapwise excitation amplitude causes phenomena like jumps, period doubling, multi and quasi-periodic solutions to occur.

Elementary excitations in single-chain magnets

Science.gov (United States)

Lutz, Philipp; Aguilà, David; Mondal, Abhishake; Pinkowicz, Dawid; Marx, Raphael; Neugebauer, Petr; Fâk, Björn; Ollivier, Jacques; Clérac, Rodolphe; van Slageren, Joris

2017-09-01

Single-chain magnets (SCMs) are one-dimensional coordination polymers or spin chains that display slow relaxation of the magnetization. Typically their static magnetic properties are described by the Heisenberg model, while the description of their dynamic magnetic properties is based on an Ising-like model. The types of excitations predicted by these models (collective vs localized) are quite different. Therefore we probed the nature of the elementary excitations for two SCMs abbreviated Mn2Ni and Mn2Fe , as well as a mononuclear derivative of the Mn2Fe chain, by means of high-frequency electron paramagnetic resonance spectroscopy (HFEPR) and inelastic neutron scattering (INS). We find that the HFEPR spectra of the chains are clearly distinct from those of the monomer. The momentum transfer dependence of the INS intensity did not reveal significant dispersion, indicating an essentially localized nature of the excitations. At the lowest temperatures these are modified by the occurrence of short-range correlations.

Structures excited by heavy ions in 208Pb target. Interpretation involving giant resonances and multiphonon excitations

International Nuclear Information System (INIS)

Chomaz, P.

1984-01-01

Kinetic energy spectra of heavy fragments from the 36Ar+208Pb reaction at 11 MeV/n and 20 Ne+ 208 Pb at 30 MeV/n have been measured with a time of flight spectrometer. Numerous structures ranging up to 100 MeV excitation energy are observed in the inelastic and few nucleon transfer channels. These structures are shown to be due to an excitation of the 208 Pb target nucleus and not to decay products of excited ejectiles. Positions of low lying structures (E* 208 Pb. The linear response of the target nucleus to the external field created by the projectile is calculated microscopically in the Random Phase Approximation resolved using the Green's function method in coordinate space with a Skyrme interaction. In the independant quasi-boson approximation multiple phonon excitations reproduce the main features of the experimental data and appear as a plausible interpretation of the observed structures. The theoretical calculations and experimental observations suggest that multiphonon excitations play an important role in heavy ion reactions and contribute strongly to the kinetic energy dissipation [fr

Decay of a Jπ=36+ Resonance in the 24Mg+24Mg Reaction

International Nuclear Information System (INIS)

Salsac, M.-D.; Haas, F.; Courtin, S.

2005-01-01

For the 24 Mg+ 24 Mg reaction, striking narrow and correlated resonance structures have been observed previously in the excitation functions of the elastic and low-lying channels. In our study we have decided to focus on the resonance at E C M =45.7 MeV, which is known to have J π =36 + . Despite the very high excitation energy(∼60 MeV) in the 48 Cr composite system, this resonance has a narrow total width of 170 keV. To determine precisely which states in the inelastic 24 Mg channels carry away the resonance flux, an experiment, on the 24 Mg + 24 Mg reaction at energies On and OFF resonance, has been performed at the Legnaro Tandem accelerator using the Prisma fragment spectrometer associated with the CLARA γ array

Exploring the resonant vibration of thin plates: Reconstruction of Chladni patterns and determination of resonant wave numbers.

Science.gov (United States)

Tuan, P H; Wen, C P; Chiang, P Y; Yu, Y T; Liang, H C; Huang, K F; Chen, Y F

2015-04-01

The Chladni nodal line patterns and resonant frequencies for a thin plate excited by an electronically controlled mechanical oscillator are experimentally measured. Experimental results reveal that the resonant frequencies can be fairly obtained by means of probing the variation of the effective impedance of the exciter with and without the thin plate. The influence of the extra mass from the central exciter is confirmed to be insignificant in measuring the resonant frequencies of the present system. In the theoretical aspect, the inhomogeneous Helmholtz equation is exploited to derive the response function as a function of the driving wave number for reconstructing experimental Chladni patterns. The resonant wave numbers are theoretically identified with the maximum coupling efficiency as well as the maximum entropy principle. Substituting the theoretical resonant wave numbers into the derived response function, all experimental Chladni patterns can be excellently reconstructed. More importantly, the dispersion relationship for the flexural wave of the vibrating plate can be determined with the experimental resonant frequencies and the theoretical resonant wave numbers. The determined dispersion relationship is confirmed to agree very well with the formula of the Kirchhoff-Love plate theory.

Review of high excitation energy structures in heavy ion collisions: target excitations and three body processes