Microwave quantum logic spectroscopy and control of molecular ions

DEFF Research Database (Denmark)

Shi, M.; F. Herskind, P.; Drewsen, M.

2013-01-01

the rotational state of a molecular ion and the electronic state of an atomic ion. In this setting, the atomic ion is used for read-out of the molecular ion state, in a manner analogous to quantum logic spectroscopy based on Raman transitions. In addition to high-precision spectroscopy, this setting allows...... for rotational ground state cooling, and can be considered as a candidate for the quantum information processing with polar molecular ions. All elements of our proposal can be realized with currently available technology....

Two dimensional molecular electronics spectroscopy for molecular fingerprinting, DNA sequencing, and cancerous DNA recognition.

Science.gov (United States)

Rajan, Arunkumar Chitteth; Rezapour, Mohammad Reza; Yun, Jeonghun; Cho, Yeonchoo; Cho, Woo Jong; Min, Seung Kyu; Lee, Geunsik; Kim, Kwang S

2014-02-25

Laser-driven molecular spectroscopy of low spatial resolution is widely used, while electronic current-driven molecular spectroscopy of atomic scale resolution has been limited because currents provide only minimal information. However, electron transmission of a graphene nanoribbon on which a molecule is adsorbed shows molecular fingerprints of Fano resonances, i.e., characteristic features of frontier orbitals and conformations of physisorbed molecules. Utilizing these resonance profiles, here we demonstrate two-dimensional molecular electronics spectroscopy (2D MES). The differential conductance with respect to bias and gate voltages not only distinguishes different types of nucleobases for DNA sequencing but also recognizes methylated nucleobases which could be related to cancerous cell growth. This 2D MES could open an exciting field to recognize single molecule signatures at atomic resolution. The advantages of the 2D MES over the one-dimensional (1D) current analysis can be comparable to those of 2D NMR over 1D NMR analysis.

Molecularization in nutritional science: a view from philosophy of science.

Science.gov (United States)

Ströhle, Alexander; Döring, Frank

2010-10-01

Over the past decade, a trend toward molecularization, which could be observed in almost all bioscientific disciplines, now appears to have also developed in nutritional science. However, molecular nutrition research gives birth to a series of questions. Therefore, we take a look at the epistemological foundation of (molecular) nutritional science. We (i) analyze the scientific status of (molecular) nutritional science and its position in the canon of other scientific disciplines, (ii) focus on the cognitive aims of nutritional science in general and (iii) on the chances and limits of molecular nutrition research in particular. By taking up the thoughts of an earlier work, we are analyzing (molecular) nutritional science from a strictly realist and emergentist-naturalist perspective. Methodologically, molecular nutrition research is bound to a microreductive research approach. We emphasize, however, that it need not be a radical microreductionism whose scientific reputation is not the best. Instead we favor moderate microreductionism, which combines reduction with integration. As mechanismic explanations are one of the primary aims of factual sciences, we consider it as the task of molecular nutrition research to find profound, i.e. molecular-mechanismic, explanations for the conditions, characteristics and changes of organisms related to the organism-nutrition environment interaction.

Improving transition voltage spectroscopy of molecular junctions

DEFF Research Database (Denmark)

Markussen, Troels; Chen, Jingzhe; Thygesen, Kristian Sommer

2011-01-01

Transition voltage spectroscopy (TVS) is a promising spectroscopic tool for molecular junctions. The principles in TVS is to find the minimum on a Fowler-Nordheim plot where ln(I/V2) is plotted against 1/V and relate the voltage at the minimum Vmin to the closest molecular level. Importantly, Vmin...

Moessbauer Spectroscopy in Materials Science

International Nuclear Information System (INIS)

2006-01-01

The publication in electronic form has been set up as proceedings of the conference dealing with applications of the Moessbauer spectroscopy in material science. Twenty-three abstracts and twenty-two presentations are included.

Molecular sciences

International Nuclear Information System (INIS)

Anon.

1975-01-01

The research in molecular sciences summarized includes photochemistry, radiation chemistry, geophysics, electromechanics, heavy-element oxidizers , heavy element chemistry collisions, atoms, organic solids. A list of publications is included

Linear and Nonlinear Molecular Spectroscopy with Laser Frequency Combs

Science.gov (United States)

Picque, Nathalie

2013-06-01

The regular pulse train of a mode-locked femtosecond laser can give rise to a comb spectrum of millions of laser modes with a spacing precisely equal to the pulse repetition frequency. Laser frequency combs were conceived a decade ago as tools for the precision spectroscopy of atomic hydrogen. They are now becoming enabling tools for an increasing number of applications, including molecular spectroscopy. Recent experiments of multi-heterodyne frequency comb Fourier transform spectroscopy (also called dual-comb spectroscopy) have demonstrated that the precisely spaced spectral lines of a laser frequency comb can be harnessed for new techniques of linear absorption spectroscopy. The first proof-of-principle experiments have demonstrated a very exciting potential of dual-comb spectroscopy without moving parts for ultra-rapid and ultra-sensitive recording of complex broad spectral bandwidth molecular spectra. Compared to conventional Michelson-based Fourier transform spectroscopy, recording times could be shortened from seconds to microseconds, with intriguing prospects for spectroscopy of short lived transient species. The resolution improves proportionally to the measurement time. Therefore longer recordings allow high resolution spectroscopy of molecules with extreme precision, since the absolute frequency of each laser comb line can be known with the accuracy of an atomic clock. Moreover, since laser frequency combs involve intense ultrashort laser pulses, nonlinear interactions can be harnessed. Broad spectral bandwidth ultra-rapid nonlinear molecular spectroscopy and imaging with two laser frequency combs is demonstrated with coherent Raman effects and two-photon excitation. Real-time multiplex accessing of hyperspectral images may dramatically expand the range of applications of nonlinear microscopy. B. Bernhardt et al., Nature Photonics 4, 55-57 (2010); A. Schliesser et al. Nature Photonics 6, 440-449 (2012); T. Ideguchi et al. arXiv:1201.4177 (2012) T

Applications of Raman spectroscopy in life science

Science.gov (United States)

Martin, Airton A.; T. Soto, Cláudio A.; Ali, Syed M.; Neto, Lázaro P. M.; Canevari, Renata A.; Pereira, Liliane; Fávero, Priscila P.

2015-06-01

Raman spectroscopy has been applied to the analysis of biological samples for the last 12 years providing detection of changes occurring at the molecular level during the pathological transformation of the tissue. The potential use of this technology in cancer diagnosis has shown encouraging results for the in vivo, real-time and minimally invasive diagnosis. Confocal Raman technics has also been successfully applied in the analysis of skin aging process providing new insights in this field. In this paper it is presented the latest biomedical applications of Raman spectroscopy in our laboratory. It is shown that Raman spectroscopy (RS) has been used for biochemical and molecular characterization of thyroid tissue by micro-Raman spectroscopy and gene expression analysis. This study aimed to improve the discrimination between different thyroid pathologies by Raman analysis. A total of 35 thyroid tissues samples including normal tissue (n=10), goiter (n=10), papillary (n=10) and follicular carcinomas (n=5) were analyzed. The confocal Raman spectroscopy allowed a maximum discrimination of 91.1% between normal and tumor tissues, 84.8% between benign and malignant pathologies and 84.6% among carcinomas analyzed. It will be also report the application of in vivo confocal Raman spectroscopy as an important sensor for detecting advanced glycation products (AGEs) on human skin.

Time-resolved vibrational spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Tokmakoff, Andrei [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Champion, Paul [Northeastern Univ., Boston, MA (United States); Heilweil, Edwin J. [National Inst. of Standards and Technology (NIST), Boulder, CO (United States); Nelson, Keith A. [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Ziegler, Larry [Boston Univ., MA (United States)

2009-05-14

This document contains the Proceedings from the 14th International Conference on Time-Resolved Vibrational Spectroscopy, which was held in Meredith, NH from May 9-14, 2009. The study of molecular dynamics in chemical reaction and biological processes using time-resolved spectroscopy plays an important role in our understanding of energy conversion, storage, and utilization problems. Fundamental studies of chemical reactivity, molecular rearrangements, and charge transport are broadly supported by the DOE's Office of Science because of their role in the development of alternative energy sources, the understanding of biological energy conversion processes, the efficient utilization of existing energy resources, and the mitigation of reactive intermediates in radiation chemistry. In addition, time-resolved spectroscopy is central to all fiveof DOE's grand challenges for fundamental energy science. The Time-Resolved Vibrational Spectroscopy conference is organized biennially to bring the leaders in this field from around the globe together with young scientists to discuss the most recent scientific and technological advances. The latest technology in ultrafast infrared, Raman, and terahertz spectroscopy and the scientific advances that these methods enable were covered. Particular emphasis was placed on new experimental methods used to probe molecular dynamics in liquids, solids, interfaces, nanostructured materials, and biomolecules.

FTIR spectroscopy applications in forensic science

International Nuclear Information System (INIS)

Roux, C.; Maynard, P.; Dawson, M.

1999-01-01

Infrared spectroscopy, and especially Fourier transform infrared spectroscopy, is a well-established technique in analytical chemistry and finds widespread application in qualitative and quantitative analyses. Infrared spectra depend on the nature of the functional groups present in the analyte, and are generally complex with numerous maxima and minima. These features are useful for comparison purposes and, in most cases, the infrared spectrum of an organic compound is considered as a unique functional print of this compound (i e the infrared spectrum constitutes the chemical signature or fingerprint of an organic compound). Many inorganic substances may also be uniquely identified using infrared spectroscopy. Until recently, infrared spectroscopy was of only limited utility in forensic science, despite its high selectivity. This is because infrared spectroscopy suffered from a lack of sensitivity in its early forms. However, with the advance of modern technology this is no longer the case. The widespread use of microscope attachments, along with numerous new sampling accessories, has overcome most of the previous limitations. For example, with an infrared microscope, it is possible to focus the infrared beam, and therefore select relevant areas of the sample as small as 10 x 10 μm and achieve a measurement in situ. Such a configuration enables the rapid generation of high-resolution spectra from samples of 10 ng. Typical forensic applications include the analysis of single textile fibres, minute paint chips or smears, drugs, laser printer and photocopy toners, polymers and miscellaneous unknown substances. Here we will broadly review the most common applications of infrared spectroscopy in forensic science

Theory and spectroscopy

Science.gov (United States)

Stanton, John F.

2015-05-01

The interaction between quantum-mechanical theory and spectroscopy is one of the most fertile interfaces in all of science, and has a richly storied history. Of course it was spectroscopy that provided essentially all of the evidence that not all was well (or, perhaps more correctly put, complete) with the world of 19th century classical physics. From the discoveries of the dark lines in the solar spectrum by Fraunhöfer in 1814 to the curiously simple geometric formula discovered seventy years later that described the hydrogen atom spectrum, spectroscopy and spectroscopists have consistently identified the areas of atomic and molecular science that are most in need of hard thinking by theoreticians. The rest of the story, of course, is well-known: spectroscopic results were used to understand and motivate the theory of radioactivity and ultimately the quantum theory, first in its immature form that was roughly contemporaneous with the first World War, and then the Heisenberg-Schrödinger-Dirac version that has withstood the test of time. Since the basic principles of quantum mechanics ware first understood, the subject has been successfully used to understand the patterns found in spectra, and how these relate to molecular structure, symmetry, energy levels, and dynamics. But further understanding required to attain these intellectual achievements has often come only as a result of vital and productive interactions between theoreticians and spectroscopists (of course, many people have strengths in both areas). And indeed, a field that might be termed "theoretical spectroscopy" was cultivated and is now an important part of modern molecular science.

Laser-induced blurring of molecular structure information in high harmonic spectroscopy

DEFF Research Database (Denmark)

Risoud, Francois; Leveque, Camille; Labeye, Marie

2017-01-01

High harmonic spectroscopy gives access to molecular structure with Angstrom resolution. Such information is encoded in the destructive interferences occurring between the harmonic emissions from the different parts of the molecule. By solving the time-dependent Schrodinger equation, either....... These findings have important consequences for molecular imaging and orbital tomography using high harmonic spectroscopy....

Molecular science for drug development and biomedicine.

Science.gov (United States)

Zhong, Wei-Zhu; Zhou, Shu-Feng

2014-11-04

With the avalanche of biological sequences generated in the postgenomic age, molecular science is facing an unprecedented challenge, i.e., how to timely utilize the huge amount of data to benefit human beings. Stimulated by such a challenge, a rapid development has taken place in molecular science, particularly in the areas associated with drug development and biomedicine, both experimental and theoretical. The current thematic issue was launched with the focus on the topic of "Molecular Science for Drug Development and Biomedicine", in hopes to further stimulate more useful techniques and findings from various approaches of molecular science for drug development and biomedicine.[...].

Practical guide to surface science and spectroscopy

CERN Document Server

Chung, Yip-Wah

2001-01-01

Practical Guide to Surface Science and Spectroscopy provides a practical introduction to surface science as well as describes the basic analytical techniques that researchers use to understand what occurs at the surfaces of materials and at their interfaces. These techniques include auger electron spectroscopy, photoelectron spectroscopy, inelastic scattering of electrons and ions, low energy electron diffraction, scanning probe microscopy, and interfacial segregation. Understanding the behavior of materials at their surfaces is essential for materials scientists and engineers as they design and fabricate microelectronics and semiconductor devices. The book gives over 100 examples, discussion questions and problems with varying levels of difficulty. Included with this book is a CD-ROM, which not only contains the same information, but also provides many elements of animation and interaction that are not easily emulated on paper. In diverse subject matters ranging from the operation of ion pumps, computer-...

Probing molecular orientations in thin films by x-ray photoelectron spectroscopy

Science.gov (United States)

Li, Y.; Li, P.; Lu, Z.-H.

2018-03-01

A great number of functional organic molecules in active thin-film layers of optoelectronic devices have highly asymmetric structures, such as plate-like, rod-like, etc. This makes molecular orientation an important aspect in thin-films as it can significantly affect both the optical and electrical performance of optoelectronic devices. With a combination of in-situ ultra violet photoelectron spectroscopy (UPS) and x-ray photoelectron spectroscopy (XPS) investigations for organic molecules having a broad range of structural properties, we discovered a rigid connection of core levels and frontier highest occupied molecular orbital levels at organic interfaces. This finding opens up opportunities of using X-ray photoemission spectroscopy as an alternative tool to UPS for providing an easy and unambiguous data interpretation in probing molecular orientations.

Contributions to advances in blend pellet products (BPP) research on molecular structure and molecular nutrition interaction by advanced synchrotron and globar molecular (Micro)spectroscopy.

Science.gov (United States)

Guevara-Oquendo, Víctor H; Zhang, Huihua; Yu, Peiqiang

2018-04-13

To date, advanced synchrotron-based and globar-sourced techniques are almost unknown to food and feed scientists. There has been little application of these advanced techniques to study blend pellet products at a molecular level. This article aims to provide recent research on advanced synchrotron and globar vibrational molecular spectroscopy contributions to advances in blend pellet products research on molecular structure and molecular nutrition interaction. How processing induced molecular structure changes in relation to nutrient availability and utilization of the blend pellet products. The study reviews Utilization of co-product components for blend pellet product in North America; Utilization and benefits of inclusion of pulse screenings; Utilization of additives in blend pellet products; Application of pellet processing in blend pellet products; Conventional evaluation techniques and methods for blend pellet products. The study focus on recent applications of cutting-edge vibrational molecular spectroscopy for molecular structure and molecular structure association with nutrient utilization in blend pellet products. The information described in this article gives better insight on how advanced molecular (micro)spectroscopy contributions to advances in blend pellet products research on molecular structure and molecular nutrition interaction.

Probing molecular orientations in thin films by x-ray photoelectron spectroscopy

Directory of Open Access Journals (Sweden)

Y. Li

2018-03-01

Full Text Available A great number of functional organic molecules in active thin-film layers of optoelectronic devices have highly asymmetric structures, such as plate-like, rod-like, etc. This makes molecular orientation an important aspect in thin-films as it can significantly affect both the optical and electrical performance of optoelectronic devices. With a combination of in-situ ultra violet photoelectron spectroscopy (UPS and x-ray photoelectron spectroscopy (XPS investigations for organic molecules having a broad range of structural properties, we discovered a rigid connection of core levels and frontier highest occupied molecular orbital levels at organic interfaces. This finding opens up opportunities of using X-ray photoemission spectroscopy as an alternative tool to UPS for providing an easy and unambiguous data interpretation in probing molecular orientations.

Using vibrational molecular spectroscopy to reveal association of steam-flaking induced carbohydrates molecular structural changes with grain fractionation, biodigestion and biodegradation

Science.gov (United States)

Xu, Ningning; Liu, Jianxin; Yu, Peiqiang

2018-04-01

Advanced vibrational molecular spectroscopy has been developed as a rapid and non-destructive tool to reveal intrinsic molecular structure conformation of biological tissues. However, this technique has not been used to systematically study flaking induced structure changes at a molecular level. The objective of this study was to use vibrational molecular spectroscopy to reveal association between steam flaking induced CHO molecular structural changes in relation to grain CHO fractionation, predicted CHO biodegradation and biodigestion in ruminant system. The Attenuate Total Reflectance Fourier-transform Vibrational Molecular Spectroscopy (ATR-Ft/VMS) at SRP Key Lab of Molecular Structure and Molecular Nutrition, Ministry of Agriculture Strategic Research Chair Program (SRP, University of Saskatchewan) was applied in this study. The fractionation, predicted biodegradation and biodigestion were evaluated using the Cornell Net Carbohydrate Protein System. The results show that: (1) The steam flaking induced significant changes in CHO subfractions, CHO biodegradation and biodigestion in ruminant system. There were significant differences between non-processed (raw) and steam flaked grain corn (P R2 = 0.87, RSD = 0.74, P R2 = 0.87, RSD = 0.24, P < .01). In summary, the processing induced molecular CHO structure changes in grain corn could be revealed by the ATR-Ft/VMS vibrational molecular spectroscopy. These molecular structure changes in grain were potentially associated with CHO biodegradation and biodigestion.

Neutron molecular spectroscopy: future prospects

International Nuclear Information System (INIS)

Tomkinson, J.; Carlile, C.J.; Krishna, P.S.R.

1994-07-01

The recent revolution in Neutron Molecular Spectroscopy, caused by extending the spectral range, is briefly reviewed. The need to constantly improve the spectral resolution is underlined and the likely benefits are identified. Recent work on improving the energy resolution on TFXA is presented and three future options for TFXA are outlined. Some preliminary high resolution results, from a mock-up spectrometer, are reported. These clearly show that narrow bands are available in solids and improved resolutions can be achieved to observe them. (Author)

Femtosecond laser spectroscopy

CERN Document Server

Hannaford, Peter

2005-01-01

As concepts and methodologies have evolved over the past two decades, the realm of ultrafast science has become vast and exciting and has impacted many areas of chemistry, biology and physics, and other fields such as materials science, electrical engineering, and optical communication. The field has recently exploded with the announcement of a series of remarkable new developments and advances. This volume surveys this recent growth in eleven chapters written by leading international researchers in the field. It includes sections on femtosecond optical frequency combs, soft x-ray femtosecond laser sources, and attosecond laser sources. In addition, the contributors address real-time spectroscopy of molecular vibrations with sub-5-fs pulses and multidimensional femtosecond coherent spectroscopies for studying molecular and electron dynamics. Novel methods for measuring and characterizing ultrashort laser pulses and ultrashort pulses of light are also described. The topics covered are revolutionizing the field...

Quantifying transition voltage spectroscopy of molecular junctions: Ab initio calculations

DEFF Research Database (Denmark)

Chen, Jingzhe; Markussen, Troels; Thygesen, Kristian Sommer

2010-01-01

Transition voltage spectroscopy (TVS) has recently been introduced as a spectroscopic tool for molecular junctions where it offers the possibility to probe molecular level energies at relatively low bias voltages. In this work we perform extensive ab initio calculations of the nonlinear current...

Raman spectroscopy as an advanced structural nanoprobe for conjugated molecular semiconductors

International Nuclear Information System (INIS)

Wood, Sebastian; Hollis, Joseph Razzell; Kim, Ji-Seon

2017-01-01

Raman spectroscopy has emerged as a powerful and important characterisation tool for probing molecular semiconducting materials. The useful optoelectronic properties of these materials arise from the delocalised π -electron density in the conjugated core of the molecule, which also results in large Raman scattering cross-sections and a strong coupling between its electronic states and vibrational modes. For this reason, Raman spectroscopy offers a unique insight into the properties of molecular semiconductors, including: chemical structure, molecular conformation, molecular orientation, and fundamental photo- and electro-chemical processes—all of which are critically important to the performance of a wide range of optical and electronic organic semiconductor devices. Experimentally, Raman spectroscopy is non-intrusive, non-destructive, and requires no special sample preparation, and so is suitable for a wide range of in situ measurements, which are particularly relevant to issues of thermal and photochemical stability. Here we review the development of the family of Raman spectroscopic techniques, which have been applied to the study of conjugated molecular semiconductors. We consider the suitability of each technique for particular circumstances, and the unique insights it can offer, with a particular focus on the significance of these measurements for the continuing development of stable, high performance organic electronic devices. (topical review)

Positron spectroscopy as an analytical tool in material sciences

International Nuclear Information System (INIS)

Pujari, P.K.

2010-01-01

Full text: Positron annihilation spectroscopy has emerged as a powerful tool in material sciences due to its ability to provide information about the electron momentum distribution and electron density in a given medium. These features help in identifying altered state of electronic rearrangements as one encounters in phase transitions. In addition, positrons prefer regions of lower electron density such as open volume defects i.e. vacancies or vacancy clusters in metals, alloys and semiconductors or free-volumes in molecular solids. Its sensitivity to defects is extremely high e.g. it can detect as small a defect as monovacancy to concentration as low as parts per million(ppm). Innovative nuclear instrumentation has helped in getting chemical specificity at the annihilation site. For example, precipitates, embedded, nanoparticles or element decorated vacancies can now be easily identified. This presentation is structured to introduce the technique and provide a global perspective on area of applications. Specific examples on defect characterization, nanostructure-property correlations in polymers, advantages of elemental specificity by indexing the core electron momentum will be given. In addition, slow positron beam based studies on nanostructured materials as well as particle accelerator based positron spectroscopy for volumetric assay of defects in large engineering samples will be presented

Molecular Imprinting Applications in Forensic Science.

Science.gov (United States)

Yılmaz, Erkut; Garipcan, Bora; Patra, Hirak K; Uzun, Lokman

2017-03-28

Producing molecular imprinting-based materials has received increasing attention due to recognition selectivity, stability, cast effectiveness, and ease of production in various forms for a wide range of applications. The molecular imprinting technique has a variety of applications in the areas of the food industry, environmental monitoring, and medicine for diverse purposes like sample pretreatment, sensing, and separation/purification. A versatile usage, stability and recognition capabilities also make them perfect candidates for use in forensic sciences. Forensic science is a demanding area and there is a growing interest in molecularly imprinted polymers (MIPs) in this field. In this review, recent molecular imprinting applications in the related areas of forensic sciences are discussed while considering the literature of last two decades. Not only direct forensic applications but also studies of possible forensic value were taken into account like illicit drugs, banned sport drugs, effective toxins and chemical warfare agents in a review of over 100 articles. The literature was classified according to targets, material shapes, production strategies, detection method, and instrumentation. We aimed to summarize the current applications of MIPs in forensic science and put forth a projection of their potential uses as promising alternatives for benchmark competitors.

Non-destructive state detection for quantum logic spectroscopy of molecular ions.

Science.gov (United States)

Wolf, Fabian; Wan, Yong; Heip, Jan C; Gebert, Florian; Shi, Chunyan; Schmidt, Piet O

2016-02-25

Precision laser spectroscopy of cold and trapped molecular ions is a powerful tool in fundamental physics--used, for example, in determining fundamental constants, testing for their possible variation in the laboratory, and searching for a possible electric dipole moment of the electron. However, the absence of cycling transitions in molecules poses a challenge for direct laser cooling of the ions, and for controlling and detecting their quantum states. Previously used state-detection techniques based on photodissociation or chemical reactions are destructive and therefore inefficient, restricting the achievable resolution in laser spectroscopy. Here, we experimentally demonstrate non-destructive detection of the quantum state of a single trapped molecular ion through its strong Coulomb coupling to a well controlled, co-trapped atomic ion. An algorithm based on a state-dependent optical dipole force changes the internal state of the atom according to the internal state of the molecule. We show that individual quantum states in the molecular ion can be distinguished by the strength of their coupling to the optical dipole force. We also observe quantum jumps (induced by black-body radiation) between rotational states of a single molecular ion. Using the detuning dependence of the state-detection signal, we implement a variant of quantum logic spectroscopy of a molecular resonance. Our state-detection technique is relevant to a wide range of molecular ions, and could be applied to state-controlled quantum chemistry and to spectroscopic investigations of molecules that serve as probes for interstellar clouds.

Use of X-ray diffraction, molecular simulations, and spectroscopy to determine the molecular packing in a polymer-fullerene bimolecular crystal

KAUST Repository

Miller, Nichole Cates

2012-09-05

The molecular packing in a polymer: fullerene bimolecular crystal is determined using X-ray diffraction (XRD), molecular mechanics (MM) and molecular dynamics (MD) simulations, 2D solid-state NMR spectroscopy, and IR absorption spectroscopy. The conformation of the electron-donating polymer is significantly disrupted by the incorporation of the electron-accepting fullerene molecules, which introduce twists and bends along the polymer backbone and 1D electron-conducting fullerene channels. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Use of X-ray diffraction, molecular simulations, and spectroscopy to determine the molecular packing in a polymer-fullerene bimolecular crystal

KAUST Repository

Miller, Nichole Cates; Cho, Eunkyung; Junk, Matthias J N; Gysel, Roman; Risko, Chad; Kim, Dongwook; Sweetnam, Sean; Miller, Chad E.; Richter, Lee J.; Kline, Regis Joseph; Heeney, Martin J.; McCulloch, Iain A.; Amassian, Aram; Acevedo-Feliz, Daniel; Knox, Christopher; Hansen, Michael Ryan; Dudenko, Dmytro V.; Chmelka, Bradley F.; Toney, Michael F.; Bré das, Jean Luc; McGehee, Michael D.

2012-01-01

The molecular packing in a polymer: fullerene bimolecular crystal is determined using X-ray diffraction (XRD), molecular mechanics (MM) and molecular dynamics (MD) simulations, 2D solid-state NMR spectroscopy, and IR absorption spectroscopy. The conformation of the electron-donating polymer is significantly disrupted by the incorporation of the electron-accepting fullerene molecules, which introduce twists and bends along the polymer backbone and 1D electron-conducting fullerene channels. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Earle K. Plyler Prize Lecture: The Three Pillars of Ultrafast Molecular Science - Time, Phase, Intensity

Science.gov (United States)

Stolow, Albert

We discuss the probing and control of molecular wavepacket dynamics in the context of three main `pillars' of light-matter interaction: time, phase, intensity. Time: Using short, coherent laser pulses and perturbative matter-field interactions, we study molecular wavepackets with a focus on the ultrafast non-Born-Oppenheimer dynamics, that is, the coupling of electronic and nuclear motions. Time-Resolved Photoelectron Spectroscopy (TRPES) is a powerful ultrafast probe of these processes in polyatomic molecules because it is sensitive both electronic and vibrational dynamics. Ideally, one would like to observe these ultrafast processes from the molecule's point of view - the Molecular Frame - thereby avoiding loss of information due to orientational averaging. This can be achieved by Time-Resolved Coincidence Imaging Spectroscopy (TRCIS) which images 3D recoil vectors of both photofragments and photoelectrons, in coincidence and as a function of time, permitting direct Molecular Frame imaging of valence electronic dynamics during a molecular dynamics. Phase: Using intermediate strength non-perturbative interactions, we apply the second order (polarizability) Non-Resonant Dynamic Stark Effect (NRDSE) to control molecular dynamics without any net absorption of light. NRDSE is also the interaction underlying molecular alignment and applies to field-free 1D of linear molecules and field-free 3D alignment of general (asymmetric) molecules. Using laser alignment, we can transiently fix a molecule in space, yielding a more general approach to direct Molecular Frame imaging of valence electronic dynamics during a chemical reaction. Intensity: In strong (ionizing) laser fields, a new laser-matter physics emerges for polyatomic systems wherein both the single active electron picture and the adiabatic electron response, both implicit in the standard 3-step models, can fail dramatically. This has important consequences for all attosecond strong field spectroscopies of

International Journal of Molecular Science 2017 Best Paper Award.

Science.gov (United States)

2017-11-02

The Editors of the International Journal of Molecular Sciences have established the Best Paper Award to recognize the most outstanding articles published in the areas of molecular biology, molecular physics and chemistry that have been published in the International Journal of Molecular Sciences. The prizes have been awarded annually since 2012 [...].

Quantum optics, molecular spectroscopy and low-temperaturespectroscopy: general discussion

Czech Academy of Sciences Publication Activity Database

Orrit, M.; Evans, G.; Cordes, T.; Kratochvílová, Irena

2015-01-01

Roč. 184, Sep (2015), 275-303 ISSN 1359-6640 R&D Projects: GA TA ČR TA04020156 Institutional support: RVO:68378271 Keywords : quantum optics * molecular spectroscopy Subject RIV: CD - Macromolecular Chemistry Impact factor: 3.544, year: 2015

Molecular Science Computing: 2010 Greenbook

Energy Technology Data Exchange (ETDEWEB)

De Jong, Wibe A.; Cowley, David E.; Dunning, Thom H.; Vorpagel, Erich R.

2010-04-02

This 2010 Greenbook outlines the science drivers for performing integrated computational environmental molecular research at EMSL and defines the next-generation HPC capabilities that must be developed at the MSC to address this critical research. The EMSL MSC Science Panel used EMSL’s vision and science focus and white papers from current and potential future EMSL scientific user communities to define the scientific direction and resulting HPC resource requirements presented in this 2010 Greenbook.

Ultrasonic spectroscopy applications in condensed matter physics and materials science

CERN Document Server

Leisure, Robert G

2017-01-01

Ultrasonic spectroscopy is a technique widely used in solid-state physics, materials science, and geology that utilizes acoustic waves to determine fundamental physical properties of materials, such as their elasticity and mechanical energy dissipation. This book provides complete coverage of the main issues relevant to the design, analysis, and interpretation of ultrasonic experiments. Topics including elasticity, acoustic waves in solids, ultrasonic loss, and the relation of elastic constants to thermodynamic potentials are covered in depth. Modern techniques and experimental methods including resonant ultrasound spectroscopy, digital pulse-echo, and picosecond ultrasound are also introduced and reviewed. This self-contained book includes extensive background theory and is accessible to students new to the field of ultrasonic spectroscopy, as well as to graduate students and researchers in physics, engineering, materials science, and geophysics.

Molecular Laser Spectroscopy as a Tool for Gas Analysis Applications

Directory of Open Access Journals (Sweden)

Javis Anyangwe Nwaboh

2011-01-01

Full Text Available We have used the traceable infrared laser spectrometric amount fraction measurement (TILSAM method to perform absolute concentration measurements of molecular species using three laser spectroscopic techniques. We report results performed by tunable diode laser absorption spectroscopy (TDLAS, quantum cascade laser absorption spectroscopy (QCLAS, and cavity ring down spectroscopy (CRDS, all based on the TILSAM methodology. The measured results of the different spectroscopic techniques are in agreement with respective gravimetric values, showing that the TILSAM method is feasible with all different techniques. We emphasize the data quality objectives given by traceability issues and uncertainty analyses.

Molecular dynamics simulation of nonlinear spectroscopies of intermolecular motions in liquid water.

Science.gov (United States)

Yagasaki, Takuma; Saito, Shinji

2009-09-15

Water is the most extensively studied of liquids because of both its ubiquity and its anomalous thermodynamic and dynamic properties. The properties of water are dominated by hydrogen bonds and hydrogen bond network rearrangements. Fundamental information on the dynamics of liquid water has been provided by linear infrared (IR), Raman, and neutron-scattering experiments; molecular dynamics simulations have also provided insights. Recently developed higher-order nonlinear spectroscopies open new windows into the study of the hydrogen bond dynamics of liquid water. For example, the vibrational lifetimes of stretches and a bend, intramolecular features of water dynamics, can be accurately measured and are found to be on the femtosecond time scale at room temperature. Higher-order nonlinear spectroscopy is expressed by a multitime correlation function, whereas traditional linear spectroscopy is given by a one-time correlation function. Thus, nonlinear spectroscopy yields more detailed information on the dynamics of condensed media than linear spectroscopy. In this Account, we describe the theoretical background and methods for calculating higher order nonlinear spectroscopy; equilibrium and nonequilibrium molecular dynamics simulations, and a combination of both, are used. We also present the intermolecular dynamics of liquid water revealed by fifth-order two-dimensional (2D) Raman spectroscopy and third-order IR spectroscopy. 2D Raman spectroscopy is sensitive to couplings between modes; the calculated 2D Raman signal of liquid water shows large anharmonicity in the translational motion and strong coupling between the translational and librational motions. Third-order IR spectroscopy makes it possible to examine the time-dependent couplings. The 2D IR spectra and three-pulse photon echo peak shift show the fast frequency modulation of the librational motion. A significant effect of the translational motion on the fast frequency modulation of the librational motion is

Application of cascaded frequency multiplication to molecular spectroscopy

International Nuclear Information System (INIS)

Drouin, Brian J.; Maiwald, Frank W.; Pearson, John C.

2005-01-01

Laboratory molecular spectroscopy provides the basis for interpretation of atmospheric, planetary, and astrophysical data gathered by remote sensing. Laboratory studies of atomic and molecular signatures across the electromagnetic spectrum provide high-precision, quantitative data used to interpret the observed environment from remote measurements. Historically, the region of the spectrum above 500 GHz has been relatively unexplored due to atmospheric absorption and technical difficulties generating and detecting radiation. Laboratory spectroscopy at these frequencies has traditionally involved measurement of one or two absorption features and relied on fitting of models to the limited data. We report a new spectrometer built around a computer-controlled commercial synthesizer and millimeter-wave module driving a series of amplifiers followed by a series of wide-bandwidth frequency doublers and triplers. The spectrometer provides the ability to rapidly measure large pieces of frequency space with higher resolution, accuracy, and sensitivity than with Fourier transform infrared techniques. The approach is simple, modular, and requires no custom-built electronics or high voltage and facilitates the use of infrared data analysis techniques on complex submillimeter spectra

Photoelectron spectroscopy of molecular beams

International Nuclear Information System (INIS)

Berkowitz, J.

1974-01-01

The history of physical science is replete with examples of phenomena initially discovered and investigated by physicists, which have subsequently become tools of the chemist. It is demonstrated in this paper that the field of photoelectron spectroscopy may develop in a reverse fashion. After a brief introduction to the subject, the properties characterized as physical ones, are discussed. These are intensities and angular distributions, from which one can infer transition probabilities and phase shifts. Three separate experiments are described which involve accurate intensity measurements and it is shown how an interpretation of the results by appropriate theory has given new insight into the photoionization process. (B.R.H.)

Molecular Science Computing Facility Scientific Challenges: Linking Across Scales

Energy Technology Data Exchange (ETDEWEB)

De Jong, Wibe A.; Windus, Theresa L.

2005-07-01

The purpose of this document is to define the evolving science drivers for performing environmental molecular research at the William R. Wiley Environmental Molecular Sciences Laboratory (EMSL) and to provide guidance associated with the next-generation high-performance computing center that must be developed at EMSL's Molecular Science Computing Facility (MSCF) in order to address this critical research. The MSCF is the pre-eminent computing facility?supported by the U.S. Department of Energy's (DOE's) Office of Biological and Environmental Research (BER)?tailored to provide the fastest time-to-solution for current computational challenges in chemistry and biology, as well as providing the means for broad research in the molecular and environmental sciences. The MSCF provides integral resources and expertise to emerging EMSL Scientific Grand Challenges and Collaborative Access Teams that are designed to leverage the multiple integrated research capabilities of EMSL, thereby creating a synergy between computation and experiment to address environmental molecular science challenges critical to DOE and the nation.

Committee on Atomic, Molecular, and Optical Sciences (CAMOS)

International Nuclear Information System (INIS)

1992-01-01

The Committee on Atomic, Molecular, and Optical Sciences is a standing committee under the auspices of the Board on Physics and Astronomy, Commission on Physical Sciences, Mathematics, and Applications of the National Academy of Sciences -- National Research Council. The atomic, molecular, and optical (AMO) sciences represent a broad and diverse field in which much of the research is carried out by small groups. These groups generally have not operated in concert with each other and, prior to the establishment of CAMOS, there was no single committee or organization that accepted the responsibility of monitoring the continuing development and assessing the general public health of the field as a whole. CAMOS has accepted this responsibility and currently provides a focus for the AMO community that is unique and essential. The membership of CAMOS is drawn from research laboratories in universities, industry, and government. Areas of expertise on the committee include atomic physics, molecular science, and optics. A special effort has been made to include a balanced representation from the three subfields. (A roster is attached.) CAMOS has conducted a number of studies related to the health of atomic and molecular science and is well prepared to response to requests for studies on specific issues. This report brief reviews the committee work of progress

Dual-comb spectroscopy of molecular electronic transitions in condensed phases

Science.gov (United States)

Cho, Byungmoon; Yoon, Tai Hyun; Cho, Minhaeng

2018-03-01

Dual-comb spectroscopy (DCS) utilizes two phase-locked optical frequency combs to allow scanless acquisition of spectra using only a single point detector. Although recent DCS measurements demonstrate rapid acquisition of absolutely calibrated spectral lines with unprecedented precision and accuracy, complex phase-locking schemes and multiple coherent averaging present significant challenges for widespread adoption of DCS. Here, we demonstrate Global Positioning System (GPS) disciplined DCS of a molecular electronic transition in solution at around 800 nm, where the absorption spectrum is recovered by using a single time-domain interferogram. We anticipate that this simplified dual-comb technique with absolute time interval measurement and ultrabroad bandwidth will allow adoption of DCS to tackle molecular dynamics investigation through its implementation in time-resolved nonlinear spectroscopic studies and coherent multidimensional spectroscopy of coupled chromophore systems.

Hybrid Light-Matter States in a Molecular and Material Science Perspective.

Science.gov (United States)

Ebbesen, Thomas W

2016-11-15

The notion that light and matter states can be hybridized the way s and p orbitals are mixed is a concept that is not familiar to most chemists and material scientists. Yet it has much potential for molecular and material sciences that is just beginning to be explored. For instance, it has already been demonstrated that the rate and yield of chemical reactions can be modified and that the conductivity of organic semiconductors and nonradiative energy transfer can be enhanced through the hybridization of electronic transitions. The hybridization is not limited to electronic transitions; it can be applied for instance to vibrational transitions to selectively perturb a given bond, opening new possibilities to change the chemical reactivity landscape and to use it as a tool in (bio)molecular science and spectroscopy. Such results are not only the consequence of the new eigenstates and energies generated by the hybridization. The hybrid light-matter states also have unusual properties: they can be delocalized over a very large number of molecules (up to ca. 10 5 ), and they become dispersive or momentum-sensitive. Importantly, the hybridization occurs even in the absence of light because it is the zero-point energies of the molecular and optical transitions that generate the new light-matter states. The present work is not a review but rather an Account from the author's point of view that first introduces the reader to the underlying concepts and details of the features of hybrid light-matter states. It is shown that light-matter hybridization is quite easy to achieve: all that is needed is to place molecules or a material in a resonant optical cavity (e.g., between two parallel mirrors) under the right conditions. For vibrational strong coupling, microfluidic IR cells can be used to study the consequences for chemistry in the liquid phase. Examples of modified properties are given to demonstrate the full potential for the molecular and material sciences. Finally an

Probing flexible conformations in molecular junctions by inelastic electron tunneling spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Deng, Mingsen [Department of Physics, Guizhou University, Guiyang, 550025 (China); Guizhou Provincial Key Laboratory of Computational Nano-Material Science, Institute of Applied Physics, Guizhou Normal College, Guiyang, 550018 (China); Ye, Gui; Jiang, Jun, E-mail: jiangj1@ustc.edu.cn [Department of Chemical Physics, School of Chemistry and Materials Science, University of Science and Technology of China, Hefei, 230026 (China); Cai, Shaohong, E-mail: caish@mail.gufe.edu.cn [Department of Physics, Guizhou University, Guiyang, 550025 (China); Guizhou Key Laboratory of Economic System Simulation, Guizhou University of Finance and Economics, Guiyang, 550004 (China); Sun, Guangyu [Guizhou Provincial Key Laboratory of Computational Nano-Material Science, Institute of Applied Physics, Guizhou Normal College, Guiyang, 550018 (China)

2015-01-15

The probe of flexible molecular conformation is crucial for the electric application of molecular systems. We have developed a theoretical procedure to analyze the couplings of molecular local vibrations with the electron transportation process, which enables us to evaluate the structural fingerprints of some vibrational modes in the inelastic electron tunneling spectroscopy (IETS). Based on a model molecule of Bis-(4-mercaptophenyl)-ether with a flexible center angle, we have revealed and validated a simple mathematical relationship between IETS signals and molecular angles. Our results might open a route to quantitatively measure key geometrical parameters of molecular junctions, which helps to achieve precise control of molecular devices.

Molecular Sensors for Moisture Detection by Moessbauer Spectroscopy

International Nuclear Information System (INIS)

Renz, F.; Souza, P. A. de; Klingelhoefer, G.; Goodwin, H. A.

2002-01-01

A parameter of importance in various industrial and commercial applications is sensitivity to moisture. A new class of molecular sensors which enable the qualitative and quantitative determination of air moisture (high selectivity and sensitivity) by application of Moessbauer spectroscopy as the probe technique has been investigated. The electronic properties of the iron-containing sensor depend upon the presence of moisture which is taken up by it and this process is accompanied by a change in electronic spin ground state which can be detected by Moessbauer spectroscopy. The sensor is suitable for in-field and industrial application using the recently developed Moessbauer spectrometer MIMOS II. Possible suitability for the detection of moisture in extraterrestrial environments is considered.

Far-infrared spectroscopy of lanthanide-based molecular magnetic materials

Energy Technology Data Exchange (ETDEWEB)

Haas, Sabrina

2015-05-13

This thesis demonstrates the applicability of far-infrared spectroscopy for the study of the crystal-field splitting of lanthanides in single-molecular magnetic materials. The far-infrared studies of three different kinds of single-molecular-magnetic materials, a single-ion magnet, a single-chain magnet and an exchange-coupled cluster, yielded a deeper understanding of the crystal-field splitting of the lanthanides in these materials. In addition, our results offered the opportunity to gain a deeper insight into the relaxation processes of these materials.

Large-scale theoretical calculations in molecular science - design of a large computer system for molecular science and necessary conditions for future computers

Energy Technology Data Exchange (ETDEWEB)

Kashiwagi, H [Institute for Molecular Science, Okazaki, Aichi (Japan)

1982-06-01

A large computer system was designed and established for molecular science under the leadership of molecular scientists. Features of the computer system are an automated operation system and an open self-service system. Large-scale theoretical calculations have been performed to solve many problems in molecular science, using the computer system. Necessary conditions for future computers are discussed on the basis of this experience.

Large-scale theoretical calculations in molecular science - design of a large computer system for molecular science and necessary conditions for future computers

International Nuclear Information System (INIS)

Kashiwagi, H.

1982-01-01

A large computer system was designed and established for molecular science under the leadership of molecular scientists. Features of the computer system are an automated operation system and an open self-service system. Large-scale theoretical calculations have been performed to solve many problems in molecular science, using the computer system. Necessary conditions for future computers are discussed on the basis of this experience. (orig.)

Applied spectroscopy and the science of nanomaterials

CERN Document Server

2015-01-01

This book focuses on several areas of intense topical interest related to applied spectroscopy and the science of nanomaterials. The eleven chapters in the book cover the following areas of interest relating to applied spectroscopy and nanoscience: ·         Raman spectroscopic characterization, modeling and simulation studies of carbon nanotubes, ·         Characterization of plasma discharges using laser optogalvanic spectroscopy, ·         Fluorescence anisotropy in understanding protein conformational disorder and aggregation, ·         Nuclear magnetic resonance spectroscopy in nanomedicine, ·         Calculation of Van der Waals interactions at the nanoscale, ·         Theory and simulation associated with adsorption of gases in nanomaterials, ·         Atom-precise metal nanoclusters, ·         Plasmonic properties of metallic nanostructures, two-dimensional materials, and their composites, ·         Applications of graphe...

The 45th anniversary of the Institute of Spectroscopy of the Russian Academy of Sciences (Scientific session of the Physical Sciences Division of the Russian Academy of Sciences, 23 October 2013)

International Nuclear Information System (INIS)

2014-01-01

On 23 October 2013, the out-of-town scientific session of the Physical Sciences Division of the Russian Academy of Sciences (RAS), celebrating the 45th anniversary of the Institute of Spectroscopy, RAS (ISAN in Russ. abbr.), was held at the conference hall of the Institute's building in Troitsk. The agenda of the session, announced on the website http://www.gpad.ac.ru of the Physical Sciences Division, RAS, listed the following reports: (1) Vinogradov E A (ISAN, Troitsk, Moscow) T he main achievements of ISAN from 2009 to 2013 ; (2) Balykin V I (ISAN, Troitsk, Moscow) A tomic and photonic nanooptics ; (3) Lozovik Yu E (ISAN, Troitsk, Moscow) E lectronic and collective properties of topological isolators ; (4) Yevdokimov Yu M (Engelgard Institute of Molecular Biology, RAS, Moscow), Kompanets O N (ISAN, Troitsk, Moscow) S tructural nanotechnology of DNA (liquid-crystal approach) and its applications ; (5) Chekalin S V (ISAN, Troitsk, Moscow) F emtosecond spectroscopy of promising materials . Papers written on the basis of oral reports 1, 2, 4, and 5 are published below. • Near field phonon-polariton spectroscopy as a method for studying the optical properties of nanofilms, E A Vinogradov, N N Novikova, V A Yakovlev Physics-Uspekhi, 2014, Volume 57, Number 6, Pages 604–607 • Quantum control of atoms and photons by optical nanofibers, V I Balykin Physics-Uspekhi, 2014, Volume 57, Number 6, Pages 607–615 • Structural nucleic acid nanotechnology: liquid-crystalline approach, Yu M Yevdokimov, O N Kompanets Physics-Uspekhi, 2014, Volume 57, Number 6, Pages 615–621 • Femtosecond spectroscopy of promising materials, S V Chekalin Physics-Uspekhi, 2014, Volume 57, Number 6, Pages 622–629 (conferences and symposia)

Adaptive real-time dual-comb spectroscopy

Science.gov (United States)

Ideguchi, Takuro; Poisson, Antonin; Guelachvili, Guy; Picqué, Nathalie; Hänsch, Theodor W.

2014-01-01

The spectrum of a laser frequency comb consists of several hundred thousand equally spaced lines over a broad spectral bandwidth. Such frequency combs have revolutionized optical frequency metrology and they now hold much promise for significant advances in a growing number of applications including molecular spectroscopy. Despite an intriguing potential for the measurement of molecular spectra spanning tens of nanometres within tens of microseconds at Doppler-limited resolution, the development of dual-comb spectroscopy is hindered by the demanding stability requirements of the laser combs. Here we overcome this difficulty and experimentally demonstrate a concept of real-time dual-comb spectroscopy, which compensates for laser instabilities by electronic signal processing. It only uses free-running mode-locked lasers without any phase-lock electronics. We record spectra spanning the full bandwidth of near-infrared fibre lasers with Doppler-limited line profiles highly suitable for measurements of concentrations or line intensities. Our new technique of adaptive dual-comb spectroscopy offers a powerful transdisciplinary instrument for analytical sciences. PMID:24572636

Adaptive real-time dual-comb spectroscopy

Science.gov (United States)

Ideguchi, Takuro; Poisson, Antonin; Guelachvili, Guy; Picqué, Nathalie; Hänsch, Theodor W.

2014-02-01

The spectrum of a laser frequency comb consists of several hundred thousand equally spaced lines over a broad spectral bandwidth. Such frequency combs have revolutionized optical frequency metrology and they now hold much promise for significant advances in a growing number of applications including molecular spectroscopy. Despite an intriguing potential for the measurement of molecular spectra spanning tens of nanometres within tens of microseconds at Doppler-limited resolution, the development of dual-comb spectroscopy is hindered by the demanding stability requirements of the laser combs. Here we overcome this difficulty and experimentally demonstrate a concept of real-time dual-comb spectroscopy, which compensates for laser instabilities by electronic signal processing. It only uses free-running mode-locked lasers without any phase-lock electronics. We record spectra spanning the full bandwidth of near-infrared fibre lasers with Doppler-limited line profiles highly suitable for measurements of concentrations or line intensities. Our new technique of adaptive dual-comb spectroscopy offers a powerful transdisciplinary instrument for analytical sciences.

Adiabatic Cooling for Rovibrational Spectroscopy of Molecular Ions

DEFF Research Database (Denmark)

Fisher, Karin

2017-01-01

The field of cold molecular ions is a fast growing one, with applications in high resolution spectroscopy and metrology, the search for time variations of fundamental constants, cold chemistry and collisions, and quantum information processing, to name a few. The study of single molecular ions...... is attractive as it enables one to push the limits of spectroscopic accuracy. Non-destructive spectroscopic detection of molecular ions can be achieved by co-trapping with an easier to detect atomic ion. The ion chain has coupled motion, and transitions which change both the internal and motional states...... to the measured heating rates, almost perfectly fitting existing heating rate theory. Further, the same model successfully predicted the heating rates of the in-phase mode of a two-ion crystal, indicating that we can use it to predict the heating rates in experiments on molecule-atom chains. Adiabatic cooling...

Committee on Atomic, Molecular, and Optical Sciences (CAMOS)

International Nuclear Information System (INIS)

1992-01-01

The Committee on Atomic, Molecular and Optical Sciences (CAMOS) of the National Research Council (NRC) is charged with monitoring the health of the field of atomic, molecular, and optical (AMO) science in the United States. Accordingly, the Committee identifies and examines both broad and specific issues affecting the field. Regular meetings, teleconferences, briefings from agencies and the scientific community, the formation of study panels to prepare reports, and special symposia are among the mechanisms used by the CAMOS to meet its charge. This progress report presents a review of CAMOS activities from February 1, 1992 to January 31, 1993. This report also includes the status of activities associated with the CAMOS study on the field that is being conducted by the Panel on the Future of Atomic, Molecular, and Optical Sciences (FAMOS)

Molecular orientation in aligned electrospun polyimide nanofibers by polarized FT-IR spectroscopy.

Science.gov (United States)

Yang, Haoqi; Jiang, Shaohua; Fang, Hong; Hu, Xiaowu; Duan, Gaigai; Hou, Haoqing

2018-07-05

Quantitative explanation on the improved mechanical properties of aligned electrospun polyimide (PI) nanofibers as the increased imidization temperatures is highly required. In this work, polarized FT-IR spectroscopy is applied to solve this problem. Based on the polarized FT-IR spectroscopy and the molecular model in the fibers, the length of the repeat unit of PI molecule, the angle between the fiber axis and the symmetric stretching direction of carbonyl group on the imide ring, and the angle between the PI molecular axis and fiber axis are all investigated. The Mark-Howink equation is used to calculate the number-average molar mass of PI molecules. The orientation states of PI molecules in the electrospun nanofibers are studied from the number-average molar mass of PI molecules and the average fiber diameter. Quantitative analysis of the orientation factor of PI molecules in the electrospun nanofibers is performed by polarized FT-IR spectroscopy. Copyright © 2018 Elsevier B.V. All rights reserved.

Raman spectroscopy on simple molecular systems at very high density

International Nuclear Information System (INIS)

Schiferl, D.; LeSar, R.S.; Moore, D.S.

1988-01-01

We present an overview of how Raman spectroscopy is done on simple molecular substances at high pressures. Raman spectroscopy is one of the most powerful tools for studying these substances. It is often the quickest means to explore changes in crystal and molecular structures, changes in bond strength, and the formation of new chemical species. Raman measurements have been made at pressures up to 200 GPa (2 Mbar). Even more astonishing is the range of temperatures (4-5200/degree/K) achieved in various static and dynamic (shock-wave) pressure experiments. One point we particularly wish to emphasize is the need for a good theoretical understanding to properly interpret and use experimental results. This is particularly true at ultra-high pressures, where strong crystal field effects can be misinterpreted as incipient insulator-metal transitions. We have tried to point out apparatus, techniques, and results that we feel are particularly noteworthy. We have also included some of the /open quotes/oral tradition/close quotes/ of high pressure Raman spectroscopy -- useful little things that rarely or never appear in print. Because this field is rapidly expanding, we discuss a number of exciting new techniques that have been informally communicated to us, especially those that seem to open new possibilities. 58 refs., 18 figs

Marine molecular biology: an emerging field of biological sciences.

Science.gov (United States)

Thakur, Narsinh L; Jain, Roopesh; Natalio, Filipe; Hamer, Bojan; Thakur, Archana N; Müller, Werner E G

2008-01-01

An appreciation of the potential applications of molecular biology is of growing importance in many areas of life sciences, including marine biology. During the past two decades, the development of sophisticated molecular technologies and instruments for biomedical research has resulted in significant advances in the biological sciences. However, the value of molecular techniques for addressing problems in marine biology has only recently begun to be cherished. It has been proven that the exploitation of molecular biological techniques will allow difficult research questions about marine organisms and ocean processes to be addressed. Marine molecular biology is a discipline, which strives to define and solve the problems regarding the sustainable exploration of marine life for human health and welfare, through the cooperation between scientists working in marine biology, molecular biology, microbiology and chemistry disciplines. Several success stories of the applications of molecular techniques in the field of marine biology are guiding further research in this area. In this review different molecular techniques are discussed, which have application in marine microbiology, marine invertebrate biology, marine ecology, marine natural products, material sciences, fisheries, conservation and bio-invasion etc. In summary, if marine biologists and molecular biologists continue to work towards strong partnership during the next decade and recognize intellectual and technological advantages and benefits of such partnership, an exciting new frontier of marine molecular biology will emerge in the future.

Molecular Environmental Science and Synchrotron Radiation Facilities An Update of the 1995 DOE-Airlie Report on Molecular Environmental Science

Energy Technology Data Exchange (ETDEWEB)

Bargar, John R

1999-05-07

This workshop was requested by Dr. Robert Marianelli, Director of the DOE-BES Chemical Sciences Division, to update the findings of the Workshop on Molecular Environmental Sciences (MES) held at Airlie, VA, in July 1995. The Airlie Workshop Report defined the new interdisciplinary field referred to as Molecular Environmental Science (MES), reviewed the synchrotron radiation methods used in MES research, assessed the adequacy of synchrotron radiation facilities for research in this field, and summarized the beam time requirements of MES users based on a national MES user survey. The objectives of MES research are to provide information on the chemical and physical forms (speciation), spatial distribution, and reactivity of contaminants in natural materials and man-made waste forms, and to develop a fundamental understanding of the complex molecular-scale environmental processes, both chemical and biological, that affect the stability, transformations, mobility, and toxicity of contaminant species. These objectives require parallel studies of ''real'' environmental samples, which are complicated multi-phase mixtures with chemical and physical heterogeneities, and of simplified model systems in which variables can be controlled and fundamental processes can be examined. Only by this combination of approaches can a basic understanding of environmental processes at the molecular-scale be achieved.

Molecular Environmental Science and Synchrotron Radiation Facilities An Update of the 1995 DOE-Airlie Report on Molecular Environmental Science

International Nuclear Information System (INIS)

Bargar, John R

1999-01-01

This workshop was requested by Dr. Robert Marianelli, Director of the DOE-BES Chemical Sciences Division, to update the findings of the Workshop on Molecular Environmental Sciences (MES) held at Airlie, VA, in July 1995. The Airlie Workshop Report defined the new interdisciplinary field referred to as Molecular Environmental Science (MES), reviewed the synchrotron radiation methods used in MES research, assessed the adequacy of synchrotron radiation facilities for research in this field, and summarized the beam time requirements of MES users based on a national MES user survey. The objectives of MES research are to provide information on the chemical and physical forms (speciation), spatial distribution, and reactivity of contaminants in natural materials and man-made waste forms, and to develop a fundamental understanding of the complex molecular-scale environmental processes, both chemical and biological, that affect the stability, transformations, mobility, and toxicity of contaminant species. These objectives require parallel studies of ''real'' environmental samples, which are complicated multi-phase mixtures with chemical and physical heterogeneities, and of simplified model systems in which variables can be controlled and fundamental processes can be examined. Only by this combination of approaches can a basic understanding of environmental processes at the molecular-scale be achieved

Large Molecule Structures by Broadband Fourier Transform Molecular Rotational Spectroscopy

Science.gov (United States)

Evangelisti, Luca; Seifert, Nathan A.; Spada, Lorenzo; Pate, Brooks

2016-06-01

Fourier transform molecular rotational resonance spectroscopy (FT-MRR) using pulsed jet molecular beam sources is a high-resolution spectroscopy technique that can be used for chiral analysis of molecules with multiple chiral centers. The sensitivity of the molecular rotational spectrum pattern to small changes in the three dimensional structure makes it possible to identify diastereomers without prior chemical separation. For larger molecules, there is the additional challenge that different conformations of each diastereomer may be present and these need to be differentiated from the diastereomers in the spectral analysis. Broadband rotational spectra of several larger molecules have been measured using a chirped-pulse FT-MRR spectrometer. Measurements of nootkatone (C15H22O), cedrol (C15H26O), ambroxide (C16H28O) and sclareolide (C16H26O2) are presented. These spectra are measured with high sensitivity (signal-to-noise ratio near 1,000:1) and permit structure determination of the most populated isomers using isotopic analysis of the 13C and 18O isotopologues in natural abundance. The accuracy of quantum chemistry calculations to identify diastereomers and conformers and to predict the dipole moment properties needed for three wave mixing measurements is examined.

Investigation of pollutant gases with molecular absorption spectroscopy

International Nuclear Information System (INIS)

Izairi, N; Ajredini, F.; Shehabi, M.

2011-01-01

This paper contains the molecular absorption spectroscopic investigation on environmental pollution by many pollutants. For this purpose a laser absorption spectroscopy at 630 nm wavelength has been applied to excite the molecular spectra in order to identify the presence of main gas pollutants. The following was the experimental procedure. Preliminary the presence of pollutants was identified. The gas champions were taken in live environment, in Tetovo streets where cars moved, and in some points in Tetovo suburbia, during different periods of the day. A special civet, part of the apparatus, has been filled by environmental air, and latter, put into the apparatus. A laser beam pulse passes throughout absorbing gas medium in the civet to excite the gas, and the absorbing spectra were automatically registered. The molecular band spectra registration has been performed by an FT-IR Spectrometer (Spectrum BX FT-IR Perkin Elmer). For this purpose the measurements were focused in spectral region of 2075 cm -1 to 2384 cm -1 for CO 2 and CO bands investigation. The importance of such measurements is to investigate the spectral properties of absorption spectra and molecular structure, and for monitoring the environmental pollution. (Author)

a Chiral Tagging Strategy for Determining Absolute Configuration and Enantiomeric Excess by Molecular Rotational Spectroscopy

Science.gov (United States)

Evangelisti, Luca; Caminati, Walther; Patterson, David; Thomas, Javix; Xu, Yunjie; West, Channing; Pate, Brooks

2017-06-01

The introduction of three wave mixing rotational spectroscopy by Patterson, Schnell, and Doyle [1,2] has expanded applications of molecular rotational spectroscopy into the field of chiral analysis. Chiral analysis of a molecule is the quantitative measurement of the relative abundances of all stereoisomers of the molecule and these include both diastereomers (with distinct molecular rotational spectra) and enantiomers (with equivalent molecular rotational spectra). This work adapts a common strategy in chiral analysis of enantiomers to molecular rotational spectroscopy. A "chiral tag" is attached to the molecule of interest by making a weakly bound complex in a pulsed jet expansion. When this tag molecule is enantiopure, it will create diastereomeric complexes with the two enantiomers of the molecule being analyzed and these can be differentiated by molecule rotational spectroscopy. Identifying the structure of this complex, with knowledge of the absolute configuration of the tag, establishes the absolute configuration of the molecule of interest. Furthermore, the diastereomer complex spectra can be used to determine the enantiomeric excess of the sample. The ability to perform chiral analysis will be illustrated by a study of solketal using propylene oxide as the tag. The possibility of using current methods of quantum chemistry to assign a specific structure to the chiral tag complex will be discussed. Finally, chiral tag rotational spectroscopy offers a "gold standard" method for determining the absolute configuration of the molecule through determination of the substitution structure of the complex. When this measurement is possible, rotational spectroscopy can deliver a quantitative three dimensional structure of the molecule with correct stereochemistry as the analysis output. [1] David Patterson, Melanie Schnell, John M. Doyle, Nature 497, 475 (2013). [2] David Patterson, John M. Doyle, Phys. Rev. Lett. 111, 023008 (2013).

On the Contribution of Raman Spectroscopy to Forensic Science

Science.gov (United States)

Buzzini, Patrick; Massonnet, Genevieve

2010-08-01

Raman spectroscopy has only recently sparked interest from forensic laboratories. The Raman technique has demonstrated important advantages such as its nondestructive nature, its fast analysis time, and especially the possibility of performing microscopical in situ analyses. In forensic applications, it is a versatile technique that covers a wide spectrum of substances such as trace evidence, illicit drugs and inks. An overview of the recent developments of Raman spectroscopy in forensic science will be discussed. Also, the requirements for an analytical technique for the examination of physical evidence will be described. Examples of casework will be depicted.

Femtochemistry and femtobiology ultrafast dynamics in molecular science

CERN Document Server

Douhal, Abderrazzak

2002-01-01

This book contains important contributions from top international scientists on the-state-of-the-art of femtochemistry and femtobiology at the beginning of the new millennium. It consists of reviews and papers on ultrafast dynamics in molecular science.The coverage of topics highlights several important features of molecular science from the viewpoint of structure (space domain) and dynamics (time domain). First of all, the book presents the latest developments, such as experimental techniques for understanding ultrafast processes in gas, condensed and complex systems, including biological mol

Laser Spectroscopy and Frequency Combs

International Nuclear Information System (INIS)

Hänsch, Theodor W; Picqué, Nathalie

2013-01-01

The spectrum of a frequency comb, commonly generated by a mode-locked femtosecond laser consists of several hundred thousand precisely evenly spaced spectral lines. Such laser frequency combs have revolutionized the art measuring the frequency of light, and they provide the long-missing clockwork for optical atomic clocks. The invention of the frequency comb technique has been motivated by precision laser spectroscopy of the simple hydrogen atom. The availability of commercial instruments is facilitating the evolution of new applications far beyond the original purpose. Laser combs are becoming powerful instruments for broadband molecular spectroscopy by dramatically improving the resolution and recording speed of Fourier spectrometers and by creating new opportunities for highly multiplexed nonlinear spectroscopy, such as two-photon spectroscopy or coherent Raman spectroscopy. Other emerging applications of frequency combs range from fundamental research in astronomy, chemistry, or attosecond science to telecommunications and satellite navigation

Using polarized Raman spectroscopy and the pseudospectral method to characterize molecular structure and function

Science.gov (United States)

Weisman, Andrew L.

Electronic structure calculation is an essential approach for determining the structure and function of molecules and is therefore of critical interest to physics, chemistry, and materials science. Of the various algorithms for calculating electronic structure, the pseudospectral method is among the fastest. However, the trade-off for its speed is more up-front programming and testing, and as a result, applications using the pseudospectral method currently lag behind those using other methods. In Part I of this dissertation, we first advance the pseudospectral method by optimizing it for an important application, polarized Raman spectroscopy, which is a well-established tool used to characterize molecular properties. This is an application of particular importance because often the easiest and most economical way to obtain the polarized Raman spectrum of a material is to simulate it; thus, utilization of the pseudospectral method for this purpose will accelerate progress in the determination of molecular properties. We demonstrate that our implementation of Raman spectroscopy using the pseudospectral method results in spectra that are just as accurate as those calculated using the traditional analytic method, and in the process, we derive the most comprehensive formulation to date of polarized Raman intensity formulas, applicable to both crystalline and isotropic systems. Next, we apply our implementation to determine the orientations of crystalline oligothiophenes -- a class of materials important in the field of organic electronics -- achieving excellent agreement with experiment and demonstrating the general utility of polarized Raman spectroscopy for the determination of crystal orientation. In addition, we derive from first-principles a method for using polarized Raman spectra to establish unambiguously whether a uniform region of a material is crystalline or isotropic. Finally, we introduce free, open-source software that allows a user to determine any of a

Doppler-free laser spectroscopy of buffer-gas-cooled molecular radicals

International Nuclear Information System (INIS)

Skoff, S M; Hendricks, R J; Sinclair, C D J; Tarbutt, M R; Hudson, J J; Segal, D M; Sauer, B E; Hinds, E A

2009-01-01

We demonstrate Doppler-free saturated absorption spectroscopy of cold molecular radicals formed by laser ablation inside a cryogenic buffer gas cell. By lowering the temperature, congested regions of the spectrum can be simplified, and by using different temperatures for different regions of the spectrum a wide range of rotational states can be studied optimally. We use the technique to study the optical spectrum of YbF radicals with a resolution of 30 MHz, measuring the magnetic hyperfine parameters of the electronic ground state. The method is suitable for high-resolution spectroscopy of a great variety of molecules at controlled temperature and pressure, and is particularly well suited to those that are difficult to produce in the gas phase.

Enzymatic and acidic degradation of high molecular weight dextran into low molecular weight and its characterizations using novel Diffusion-ordered NMR spectroscopy.

Science.gov (United States)

Iqbal, Samina; Marchetti, Roberta; Aman, Afsheen; Silipo, Alba; Qader, Shah Ali Ul; Molinaro, Antonio

2017-10-01

Low molecular weight fractions were derived from native high molecular weight dextran produced by Leuconostoc mesenteroides KIBGE-IB26. Structural characterization of native and low molecular weight fractions obtained after acidic and enzymatic hydrolysis was done using FTIR and NMR spectroscopy. The molecular weight was estimated using Diffusion Ordered NMR spectroscopy. Native dextran (892kDa) is composed of α-(1→6) glycosidic linkage along with α-(1→3) branching. Major proportion of 528kDa dextran was obtained after prolong enzymatic hydrolysis however, an effective acidic treatment at pH-1.4 up to 02 and 04h of exposure resulted in the formation of 77kDa and 57kDa, respectively. The increment in pH from 1.4 to 1.8 lowered the hydrolysis efficiency and resulted in the formation of 270kDa dextran fraction. The results suggest that derived low molecular weight water soluble fractions can be utilized as a drug delivery carrier along with multiple application relating pharmaceutical industries. Copyright © 2017 Elsevier B.V. All rights reserved.

Low-temperature, ultrahigh-vacuum tip-enhanced Raman spectroscopy combined with molecular beam epitaxy for in situ two-dimensional materials' studies

Science.gov (United States)

Sheng, Shaoxiang; Li, Wenbin; Gou, Jian; Cheng, Peng; Chen, Lan; Wu, Kehui

2018-05-01

Tip-enhanced Raman spectroscopy (TERS), which combines scanning probe microscopy with the Raman spectroscopy, is capable to access the local structure and chemical information simultaneously. However, the application of ambient TERS is limited by the unstable and poorly controllable experimental conditions. Here, we designed a high performance TERS system based on a low-temperature ultrahigh-vacuum scanning tunneling microscope (LT-UHV-STM) and combined with a molecular beam epitaxy (MBE) system. It can be used for growing two-dimensional (2D) materials and for in situ STM and TERS characterization. Using a 2D silicene sheet on the Ag(111) surface as a model system, we achieved an unprecedented 109 Raman single enhancement factor in combination with a TERS spatial resolution down to 0.5 nm. The results show that TERS combined with a MBE system can be a powerful tool to study low dimensional materials and surface science.

Ultrafast Spectroscopy of Energetic Materials: Toward a Molecular Understanding of Impact Sensitivity

National Research Council Canada - National Science Library

Dlott, Dana D

2005-01-01

... with 1.5 Angstrom resolution. With 3D spectroscopy we have studied vibrational energy transfer in water and for the first time we have been able to watch vibrational energy flow across the interface between a molecular nanostructure and its surroundings.

Marine molecular biology: An emerging field of biological sciences

Digital Repository Service at National Institute of Oceanography (India)

Thakur, N.L.; Jain, R.; Natalio, F.; Hamer, B.; Thakur, A.N.; Muller, W.E.G.

An appreciation of the potential applications of molecular biology is of growing importance in many areas of life sciences, including marine biology. During the past two decades, the development of sophisticated molecular technologies...

Deep Generative Models for Molecular Science

DEFF Research Database (Denmark)

Jørgensen, Peter Bjørn; Schmidt, Mikkel Nørgaard; Winther, Ole

2018-01-01

Generative deep machine learning models now rival traditional quantum-mechanical computations in predicting properties of new structures, and they come with a significantly lower computational cost, opening new avenues in computational molecular science. In the last few years, a variety of deep...... generative models have been proposed for modeling molecules, which differ in both their model structure and choice of input features. We review these recent advances within deep generative models for predicting molecular properties, with particular focus on models based on the probabilistic autoencoder (or...

NMR-MRI, μSR and Mössbauer Spectroscopies in Molecular Magnets

CERN Document Server

Carretta, Pietro

2007-01-01

The discovery of molecular nanomagnets showing novel quantum effects, as the quantum tunneling of the magnetization, has brought to a renewed interest for the study of molecular magnetism and multifunctional molecular material. These materials have recently triggered an intense research activity in view of their possible applicabilities as, for example, as nanosized information storage units and as magnetic nanoparticles for bio-medicine. Several fundamental aspects of the microscopic static and dynamic properties of these molecular materials have been obtained by means of spectroscopies using local probes, as nuclei and muons. In this book an extensive overview on the results obtained during the last decade and on recent achievements in the study of molecular magnets by means of Nuclear Magnetic Resonance, Muon Spin Rotation, Magnetic Resonance Imaging and Mossbauer techniques is presented. The aim is to introduce the reader to these techniques and to give a general background on their application to molecul...

Fellowship | Indian Academy of Sciences

Indian Academy of Sciences (India)

Specialization: Solid State Chemistry, Surface Science, Spectroscopy and Molecular Structure Address: Linus Pauling Research Professor, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560 064, Karnataka Contact: Office: (080) 2365 3075, (080) 2208 2761. Residence: (080) 2360 1410

Detection of Molecular Oxygen at Low Concentrations Using Quartz Enhanced Photoacoustic Spectroscopy

Directory of Open Access Journals (Sweden)

Andreas Pohlkötter

2010-09-01

Full Text Available Molecular oxygen is detected at low concentrations using photoacoustic spectroscopy despite its unfavorable photoacoustic properties. The system consists of a seed laser diode, a tapered amplifier and a quartz tuning fork based spectrophone, thus employing quartz enhanced photoacoustic spectroscopy (QEPAS. With this system a detection limit of 13 ppm is reached with a compact and long term stable setup. Further improvement of the detection limit is possible by adding suitable gases to the sample gas that promote the radiationless de-excitation of the oxygen molecules.

The use of direct geometry spectrometers in molecular spectroscopy

International Nuclear Information System (INIS)

Parker, Stewart F; Ramirez-Cuesta, Anibal J; Albers, Peter W; Lennon, David

2014-01-01

The advantages and disadvantages of the use of direct geometry spectrometers for molecular spectroscopy and catalysis studies are described. We show that both direct and indirect geometry INS spectrometers are important tools for the study of industrially relevant areas such as catalysis, proton conductors and gas separation. We propose a novel hybrid instrument, Cerberus, that would offer high sensitivity and high-to-reasonable resolution across the entire 'mid-infrared' spectral range that would effectively advance research in these areas

Probing a molecular electronic transition by two-colour sum-frequency generation spectroscopy

International Nuclear Information System (INIS)

Humbert, C.; Dreesen, L.; Nihonyanagi, S.; Masuda, T.; Kondo, T.; Mani, A.A.; Uosaki, K.; Thiry, P.A.; Peremans, A.

2003-01-01

We demonstrate that a new emerging technique, two-colour sum-frequency generation (SFG) spectroscopy, can be used to probe the molecular electronic properties of self-assembled monolayers (SAMs). In the CH spectral range (2800-3200 cm -1 ), we show that the sum-frequency generation signal of a porphyrin alkanethiol derivative adsorbed on Pt(1 1 1) reaches a maximum intensity at ∼435 nm SFG wavelength. This wavelength corresponds to the porphyrin moiety specific π-π* molecular electronic transition which is called the Soret or B band. This resonant behaviour is not observed for 1-dodecanethiol SAMs, which are devoid of molecular electronic transition in the investigated visible spectral range

Superatom spectroscopy and the electronic state correlation between elements and isoelectronic molecular counterparts.

Science.gov (United States)

Peppernick, Samuel J; Gunaratne, K D Dasitha; Castleman, A W

2010-01-19

Detailed in the present investigation are results pertaining to the photoelectron spectroscopy of negatively charged atomic ions and their isoelectronic molecular counterparts. Experiments utilizing the photoelectron imaging technique are performed on the negative ions of the group 10 noble metal block (i.e. Ni-, Pd-, and Pt-) of the periodic table at a photon energy of 2.33 eV (532 nm). The accessible electronic transitions, term energies, and orbital angular momentum components of the bound electronic states in the atom are then compared with photoelectron images collected for isoelectronic early transition metal heterogeneous diatomic molecules, M-X- (M = Ti,Zr,W; X = O or C). A superposition principle connecting the spectroscopy between the atomic and molecular species is observed, wherein the electronic structure of the diatomic is observed to mimic that present in the isoelectronic atom. The molecular ions studied in this work, TiO-, ZrO-, and WC- can then be interpreted as possessing superatomic electronic structures reminiscent of the isoelectronic elements appearing on the periodic table, thereby quantifying the superatom concept.

Molecular Science Research Center, 1991 annual report

Energy Technology Data Exchange (ETDEWEB)

Knotek, M.L.

1992-03-01

During 1991, the Molecular Science Research Center (MSRC) experienced solid growth and accomplishment and the Environmental, and Molecular Sciences Laboratory (EMSL) construction project moved forward. We began with strong programs in chemical structure and dynamics and theory, modeling, and simulation, and both these programs continued to thrive. We also made significant advances in the development of programs in materials and interfaces and macromolecular structure and dynamics, largely as a result of the key staff recruited to lead these efforts. If there was one pervasive activity for the past year, however, it was to strengthen the role of the EMSL in the overall environmental restoration and waste management (ER/WM) mission at Hanford. These extended activities involved not only MSRC and EMSL staff but all PNL scientific and technical staff engaged in ER/WM programs.

Sum frequency generation vibrational spectroscopy (SFG-VS) for complex molecular surfaces and interfaces: Spectral lineshape measurement and analysis plus some controversial issues

Science.gov (United States)

Wang, Hong-Fei

2016-12-01

Sum-frequency generation vibrational spectroscopy (SFG-VS) was first developed in the 1980s and it has been proven a uniquely sensitive and surface/interface selective spectroscopic probe for characterization of the structure, conformation and dynamics of molecular surfaces and interfaces. In recent years, there have been many progresses in the development of methodology and instrumentation in the SFG-VS toolbox that have significantly broadened the application to complex molecular surfaces and interfaces. In this review, after presenting a unified view on the theory and methodology focusing on the SFG-VS spectral lineshape, as well as the new opportunities in SFG-VS applications with such developments, some of the controversial issues that have been puzzling the community are discussed. The aim of this review is to present to the researchers and students interested in molecular surfaces and interfacial sciences up-to-date perspectives complementary to the existing textbooks and reviews on SFG-VS.

Molecular excitation dynamics and relaxation quantum theory and spectroscopy

CERN Document Server

Valkunas, Leonas; Mancal, Tomas

2013-01-01

Meeting the need for a work that brings together quantum theory and spectroscopy to convey excitation processes to advanced students and specialists wishing to conduct research and understand the entire field rather than just single aspects.Written by an experienced author and recognized authority in the field, this text covers numerous applications and offers examples taken from different disciplines. As a result, spectroscopists, molecular physicists, physical chemists, and biophysicists will all find this a must-have for their research. Also suitable as supplementary reading in graduate

Precision spectroscopy of molecular hydrogen ions : Towards frequency metrology of particle masses

NARCIS (Netherlands)

Roth, B.; Koelemeij, J.; Schiller, S.; Hilico, L.; Karr, Jean Philippe; Korobov, V.I.; Bakalov, D.

2008-01-01

We describe the current status of high-precision ab initio calculations of the spectra of molecular hydrogen ions (H2+ and HD+) and of two experiments for vibrational spectroscopy. The perspectives for a comparison between theory and experiment at a level of 1 part in 109 are considered.

Educational challenges of molecular life science: Characteristics and implications for education and research.

Science.gov (United States)

Tibell, Lena A E; Rundgren, Carl-Johan

2010-01-01

Molecular life science is one of the fastest-growing fields of scientific and technical innovation, and biotechnology has profound effects on many aspects of daily life-often with deep, ethical dimensions. At the same time, the content is inherently complex, highly abstract, and deeply rooted in diverse disciplines ranging from "pure sciences," such as math, chemistry, and physics, through "applied sciences," such as medicine and agriculture, to subjects that are traditionally within the remit of humanities, notably philosophy and ethics. Together, these features pose diverse, important, and exciting challenges for tomorrow's teachers and educational establishments. With backgrounds in molecular life science research and secondary life science teaching, we (Tibell and Rundgren, respectively) bring different experiences, perspectives, concerns, and awareness of these issues. Taking the nature of the discipline as a starting point, we highlight important facets of molecular life science that are both characteristic of the domain and challenging for learning and education. Of these challenges, we focus most detail on content, reasoning difficulties, and communication issues. We also discuss implications for education research and teaching in the molecular life sciences.

Free radicals. High-resolution spectroscopy and molecular structure

International Nuclear Information System (INIS)

Hirota, E.

1983-01-01

High-resolution, high-sensitivity spectroscopy using CW laser and microwave sources has been applied to free radicals and transient molecules to establish their existence and to explore their properties in detail. The radicals studied were mainly generated by discharge-induced reactions. A few molecules are used as typical examples to illustrate the results so far obtained. The molecular and electronic structures of free radicals, intramolecular motions of large amplitudes in some labile molecules, and metastable electronic states of carbenes are given special emphasis. The significance of the present spectroscopic results in other related fields such as astronomy and atmospheric chemistry is stressed. 4 figures, 3 tables

Surface enhanced raman spectroscopy analytical, biophysical and life science applications

CERN Document Server

Schlücker, Sebastian

2013-01-01

Covering everything from the basic theoretical and practical knowledge to new exciting developments in the field with a focus on analytical and life science applications, this monograph shows how to apply surface-enhanced Raman scattering (SERS) for solving real world problems. From the contents: * Theory and practice of SERS * Analytical applications * SERS combined with other analytical techniques * Biophysical applications * Life science applications including various microscopies Aimed at analytical, surface and medicinal chemists, spectroscopists, biophysicists and materials scientists. Includes a Foreword by the renowned Raman spectroscopist Professor Wolfgang Kiefer, the former Editor-in-Chief of the Journal of Raman Spectroscopy.

Reverse engineering of an affinity-switchable molecular interaction characterized by atomic force microscopy single-molecule force spectroscopy.

Science.gov (United States)

Anselmetti, Dario; Bartels, Frank Wilco; Becker, Anke; Decker, Björn; Eckel, Rainer; McIntosh, Matthew; Mattay, Jochen; Plattner, Patrik; Ros, Robert; Schäfer, Christian; Sewald, Norbert

2008-02-19

Tunable and switchable interaction between molecules is a key for regulation and control of cellular processes. The translation of the underlying physicochemical principles to synthetic and switchable functional entities and molecules that can mimic the corresponding molecular functions is called reverse molecular engineering. We quantitatively investigated autoinducer-regulated DNA-protein interaction in bacterial gene regulation processes with single atomic force microscopy (AFM) molecule force spectroscopy in vitro, and developed an artificial bistable molecular host-guest system that can be controlled and regulated by external signals (UV light exposure and thermal energy). The intermolecular binding functionality (affinity) and its reproducible and reversible switching has been proven by AFM force spectroscopy at the single-molecule level. This affinity-tunable optomechanical switch will allow novel applications with respect to molecular manipulation, nanoscale rewritable molecular memories, and/or artificial ion channels, which will serve for the controlled transport and release of ions and neutral compounds in the future.

Molecular Science Research Center 1992 annual report

Energy Technology Data Exchange (ETDEWEB)

Knotek, M.L.

1994-01-01

The Molecular Science Research Center is a designated national user facility, available to scientists from universities, industry, and other national laboratories. After an opening section, which includes conferences hosted, appointments, and projects, this document presents progress in the following fields: chemical structure and dynamics; environmental dynamics and simulation; macromolecular structure and dynamics; materials and interfaces; theory, modeling, and simulation; and computing and information sciences. Appendices are included: MSRC staff and associates, 1992 publications and presentations, activities, and acronyms and abbreviations.

Precision Spectroscopy of Molecular Hydrogen and the Search for New Physics

Science.gov (United States)

Ubachs, Wim

2017-06-01

The hydrogen molecule is the smallest neutral chemical entity and a benchmark system of molecular spectroscopy. The comparison between highly accurate measurements of transition frequencies and level energies with quantum calculations including all known phenomena (relativistic, vacuum polarization and self energy) provides a tool to search for physical phenomena in the realm of the unknown: are there forces beyond the three included in the Standard Model of physics plus gravity [1], are there extra dimensions beyond the 3+1 describing space time [2] ? Comparison of laboratory wavelengths of transitions in hydrogen may be compared with the lines observed during the epoch of the early Universe to verify whether fundamental constants of Nature have varied over cosmological time [3]. These concepts, as well as the precision laboratory experiments and the astronomical observations used for such searches of new physics [4] will be discussed. [1] E.J. Salumbides, J.C.J. Koelemeij, J. Komasa, K. Pachucki, K.S.E. Eikema, W. Ubachs, Bounds on fifth forces from precision measurements on molecules, Phys. Rev. D87, 112008 (2013). [2] E.J. Salumbides, A.N. Schellekens, B. Gato-Rivera, W. Ubachs Constraints on extra dimensions from molecular spectroscopy, New. J. Phys. 17, 033015 (2015). [3] W. Ubachs, J. Bagdonaite, E.J. Salumbides, M.T. Murphy, L. Kaper, Search for a drifting proton-electron mass ratio from H_2, Rev. Mod. Phys. 88, 021003 (2016). [4] W. Ubachs, J.C.J. Koelemeij, K.S.E. Eikema, E.J. Salumbides, Physics beyond the Standard Model from hydrogen spectroscopy, J. Mol. Spectr. 320, 1 (2016).

Resonance ionization spectroscopy 1990

International Nuclear Information System (INIS)

Parks, J.E.; Omenetto, N.

1991-01-01

The Fifth International Symposium on Resonance Ionization Spectroscopy (RIS) and its Applications was held in Varese, Italy, 16-21 September 1990. Interest in RIS and its applications continues to grow, and RIS is expanding into a more diverse and mature field of study. This maturity was evident in this meeting both in the basic science and understanding of RIS processes and in the number of new and improved applications and techniques. The application of RIS techniques to molecular detection problems made remarkable progress since the last meeting two years ago. Subtle effects pertaining to isotopic discrimination received more theoretical attention, and there now seems to be good understanding of these effects, which can lead to correction procedures and/or methods to avoid isotopic effects. RIS applications were presented in which significant, real world problems were addressed, demonstrating its capability to solve problems that previously could not be accurately solved by other more traditional techniques. The contributions to the conference are grouped under the following major topic headings: physics applications of rare atoms; laser ionization mechanisms - spectroscopy; atomic, molecular and ion sources; molecular RIS; atomic RIS - Rydberg states; environmental trace analysis; biological and medical applications; state selected chemistry; new laser sources and techniques; ultra-high resolution and isotopic selectivity; surface and bulk analysis. (Author)

Emerging technology: applications of Raman spectroscopy for prostate cancer.

Science.gov (United States)

Kast, Rachel E; Tucker, Stephanie C; Killian, Kevin; Trexler, Micaela; Honn, Kenneth V; Auner, Gregory W

2014-09-01

There is a need in prostate cancer diagnostics and research for a label-free imaging methodology that is nondestructive, rapid, objective, and uninfluenced by water. Raman spectroscopy provides a molecular signature, which can be scaled from micron-level regions of interest in cells to macroscopic areas of tissue. It can be used for applications ranging from in vivo or in vitro diagnostics to basic science laboratory testing. This work describes the fundamentals of Raman spectroscopy and complementary techniques including surface enhanced Raman scattering, resonance Raman spectroscopy, coherent anti-Stokes Raman spectroscopy, confocal Raman spectroscopy, stimulated Raman scattering, and spatially offset Raman spectroscopy. Clinical applications of Raman spectroscopy to prostate cancer will be discussed, including screening, biopsy, margin assessment, and monitoring of treatment efficacy. Laboratory applications including cell identification, culture monitoring, therapeutics development, and live imaging of cellular processes are discussed. Potential future avenues of research are described, with emphasis on multiplexing Raman spectroscopy with other modalities.

Bio-functions and molecular carbohydrate structure association study in forage with different source origins revealed using non-destructive vibrational molecular spectroscopy techniques.

Science.gov (United States)

Ji, Cuiying; Zhang, Xuewei; Yan, Xiaogang; Mostafizar Rahman, M; Prates, Luciana L; Yu, Peiqiang

2017-08-05

The objectives of this study were to: 1) investigate forage carbohydrate molecular structure profiles; 2) bio-functions in terms of CHO rumen degradation characteristics and hourly effective degradation ratio of N to OM (HED N/OM ), and 3) quantify interactive association between molecular structures, bio-functions and nutrient availability. The vibrational molecular spectroscopy was applied to investigate the structure feature on a molecular basis. Two sourced-origin alfalfa forages were used as modeled forages. The results showed that the carbohydrate molecular structure profiles were highly linked to the bio-functions in terms of rumen degradation characteristics and hourly effective degradation ratio. The molecular spectroscopic technique can be used to detect forage carbohydrate structure features on a molecular basis and can be used to study interactive association between forage molecular structure and bio-functions. Copyright © 2017 Elsevier B.V. All rights reserved.

Potato agriculture, late blight science, and the molecularization of plant pathology.

Science.gov (United States)

Turner, R Steven

2008-01-01

By the mid-1980s nucleic-acid based methods were penetrating the farthest reaches of biological science, triggering rivalries among practitioners, altering relationships among subfields, and transforming the research front. This article delivers a "bottom up" analysis of that transformation at work in one important area of biological science, plant pathology, by tracing the "molecularization" of efforts to understand and control one notorious plant disease -- the late blight of potatoes. It mobilizes the research literature of late blight science as a tool through which to trace the changing typography of the research front from 1983 to 2003. During these years molecularization intensified the traditional fragmentation of the late blight research community, even as it dramatically integrated study of the causal organism into broader areas of biology. In these decades the pathogen responsible for late blight, the oomycete "Phytophthora infestans," was discovered to be undergoing massive, frightening, and still largely unexplained genetic diversification -- a circumstance that lends the episode examined here an urgency that reinforces its historiographical significance as a case-study in the molecularization of the biological sciences.

Quantum optical emulation of molecular vibronic spectroscopy using a trapped-ion device.

Science.gov (United States)

Shen, Yangchao; Lu, Yao; Zhang, Kuan; Zhang, Junhua; Zhang, Shuaining; Huh, Joonsuk; Kim, Kihwan

2018-01-28

Molecules are one of the most demanding quantum systems to be simulated by quantum computers due to their complexity and the emergent role of quantum nature. The recent theoretical proposal of Huh et al. (Nature Photon., 9, 615 (2015)) showed that a multi-photon network with a Gaussian input state can simulate a molecular spectroscopic process. Here, we present the first quantum device that generates a molecular spectroscopic signal with the phonons in a trapped ion system, using SO 2 as an example. In order to perform reliable Gaussian sampling, we develop the essential experimental technology with phonons, which includes the phase-coherent manipulation of displacement, squeezing, and rotation operations with multiple modes in a single realization. The required quantum optical operations are implemented through Raman laser beams. The molecular spectroscopic signal is reconstructed from the collective projection measurements for the two-phonon-mode. Our experimental demonstration will pave the way to large-scale molecular quantum simulations, which are classically intractable, but would be easily verifiable by real molecular spectroscopy.

Spectroscopy

DEFF Research Database (Denmark)

Berg, Rolf W.

This introductory booklet covers the basics of molecular spectroscopy, infrared and Raman methods, instrumental considerations, symmetry analysis of molecules, group theory and selection rules, as well as assignments of fundamental vibrational modes in molecules.......This introductory booklet covers the basics of molecular spectroscopy, infrared and Raman methods, instrumental considerations, symmetry analysis of molecules, group theory and selection rules, as well as assignments of fundamental vibrational modes in molecules....

Raman spectroscopy in pharmaceutical product design

DEFF Research Database (Denmark)

Paudel, Amrit; Raijada, Dhara; Rantanen, Jukka

2015-01-01

Almost 100 years after the discovery of the Raman scattering phenomenon, related analytical techniques have emerged as important tools in biomedical sciences. Raman spectroscopy and microscopy are frontier, non-invasive analytical techniques amenable for diverse biomedical areas, ranging from...... molecular-based drug discovery, design of innovative drug delivery systems and quality control of finished products. This review presents concise accounts of various conventional and emerging Raman instrumentations including associated hyphenated tools of pharmaceutical interest. Moreover, relevant...... application cases of Raman spectroscopy in early and late phase pharmaceutical development, process analysis and micro-structural analysis of drug delivery systems are introduced. Finally, potential areas of future advancement and application of Raman spectroscopic techniques are discussed....

Symmetry Breaking in NMR Spectroscopy: The Elucidation of Hidden Molecular Rearrangement Processes

Directory of Open Access Journals (Sweden)

Michael J. McGlinchey

2014-08-01

Full Text Available Variable-temperature NMR spectroscopy is probably the most convenient and sensitive technique to monitor changes in molecular structure in solution. Rearrangements that are rapid on the NMR time-scale exhibit simplified spectra, whereby non-equivalent nuclear environments yield time-averaged resonances. At lower temperatures, when the rate of exchange is sufficiently reduced, these degeneracies are split and the underlying “static” molecular symmetry, as seen by X-ray crystallography, becomes apparent. Frequently, however, such rearrangement processes are hidden, even when they become slow on the NMR time-scale, because the molecular point group remains unchanged. Judicious symmetry breaking, such as by substitution of a molecular fragment by a similar, but not identical moiety, or by the incorporation of potentially diastereotopic (chemically non-equivalent nuclei, allows the elucidation of the kinetics and energetics of such processes. Examples are chosen that include a wide range of rotations, migrations and other rearrangements in organic, inorganic and organometallic chemistry.

Fundamental Approaches in Molecular Biology for Communication Sciences and Disorders

Science.gov (United States)

Bartlett, Rebecca S.; Jette, Marie E.; King, Suzanne N.; Schaser, Allison; Thibeault, Susan L.

2012-01-01

Purpose: This contemporary tutorial will introduce general principles of molecular biology, common deoxyribonucleic acid (DNA), ribonucleic acid (RNA), and protein assays and their relevance in the field of communication sciences and disorders. Method: Over the past 2 decades, knowledge of the molecular pathophysiology of human disease has…

Resonant-enhanced spectroscopy of molecular rotations with a scanning tunneling microscope.

Science.gov (United States)

Natterer, Fabian Donat; Patthey, François; Brune, Harald

2014-07-22

We use rotational excitation spectroscopy with a scanning tunneling microscope to investigate the rotational properties of molecular hydrogen and its isotopes physisorbed on the surfaces of graphene and hexagonal boron nitride (h-BN), grown on Ni(111), Ru(0001), and Rh(111). The rotational excitation energies are in good agreement with ΔJ = 2 transitions of freely spinning p-H2 and o-D2 molecules. The variations of the spectral line shapes for H2 among the different surfaces can be traced back to a molecular resonance-mediated tunneling mechanism. Our data for H2/h-BN/Rh(111) suggest a local intrinsic gating on this surface due to lateral static dipoles. Spectra on a mixed monolayer of H2, HD, and D2 display all three J = 0 → 2 rotational transitions, irrespective of tip position, thus pointing to a multimolecule excitation, or molecular mobility in the physisorbed close-packed layer.

A molecular surface science study of the structure of adsorbates on surfaces: Importance to lubrication

International Nuclear Information System (INIS)

Mate, C.M.

1986-09-01

The interaction and bonding of atoms and molecules on metal surfaces is explored under ultra-high vacuum conditions using a variety of surface science techniques: high resolution electron energy loss spectroscopy (HREELS), low energy electron diffraction (LEED), thermal desorption spectroscopy (TDS), Auger electron spectroscopy (AES), work function measurements, and second harmonic generation (SHG). 164 refs., 51 figs., 3 tabs

Structural investigation of bistrifluron using x-ray crystallography, NMR spectroscopy, and molecular modeling

CERN Document Server

Moon, J K; Rhee, S K; Kim, G B; Yun, H S; Chung, B J; Lee, S S; Lim, Y H

2002-01-01

A new insecticide, bistrifluron acts as an inhibitor of insect development and interferes with the cuticle formation of insects. Since it shows low acute oral and dermal toxicities, it can be one of potent insecticides. Based on X-ray crystallography, NMR spectroscopy and molecular modeling, the structural studies of bistrifluron have been carried out.

Real-time reflectance-difference spectroscopy of GaAs molecular beam epitaxy homoepitaxial growth

Energy Technology Data Exchange (ETDEWEB)

Lastras-Martínez, A., E-mail: alm@cactus.iico.uaslp.mx, E-mail: alastras@gmail.com; Ortega-Gallegos, J.; Guevara-Macías, L. E.; Nuñez-Olvera, O.; Balderas-Navarro, R. E.; Lastras-Martínez, L. F. [Instituto de Investigación en Comunicación Optica, Universidad Autónoma de San Luis Potosí, Alvaro Obregón 64, San Luis Potosí, SLP 78000 (Mexico); Lastras-Montaño, L. A. [IBM T. J. Watson Research Center, Yorktown Heights, New York 10598 (United States); Lastras-Montaño, M. A. [Department of Electrical and Computer Engineering, University of California, Santa Barbara, Santa Barbara, California 93106 (United States)

2014-03-01

We report on real time-resolved Reflectance-difference (RD) spectroscopy of GaAs(001) grown by molecular beam epitaxy, with a time-resolution of 500 ms per spectrum within the 2.3–4.0 eV photon energy range. Through the analysis of transient RD spectra we demonstrated that RD line shapes are comprised of two components with different physical origins and determined their evolution during growth. Such components were ascribed to the subsurface strain induced by surface reconstruction and to surface stoichiometry. Results reported in this paper render RD spectroscopy as a powerful tool for the study of fundamental processes during the epitaxial growth of zincblende semiconductors.

Two-Dimensional Spectroscopy Is Being Used to Address Core Scientific Questions in Biology and Materials Science.

Science.gov (United States)

Petti, Megan K; Lomont, Justin P; Maj, Michał; Zanni, Martin T

2018-02-15

Two-dimensional spectroscopy is a powerful tool for extracting structural and dynamic information from a wide range of chemical systems. We provide a brief overview of the ways in which two-dimensional visible and infrared spectroscopies are being applied to elucidate fundamental details of important processes in biological and materials science. The topics covered include amyloid proteins, photosynthetic complexes, ion channels, photovoltaics, batteries, as well as a variety of promising new methods in two-dimensional spectroscopy.

Environmental Molecular Sciences Laboratory Annual Report: Fiscal Year 2006

Energy Technology Data Exchange (ETDEWEB)

Foster, Nancy S.; Showalter, Mary Ann

2007-03-23

This report describes the activities and research performed at the Environmental Molecular Sciences Laboratory, a Department of Energy national scientific user facility at Pacific Northwest National Laboratory, during Fiscal Year 2006.

Theoretical study of molecular vibrations in electron momentum spectroscopy experiments on furan: An analytical versus a molecular dynamical approach

International Nuclear Information System (INIS)

Morini, Filippo; Deleuze, Michael S.; Watanabe, Noboru; Takahashi, Masahiko

2015-01-01

The influence of thermally induced nuclear dynamics (molecular vibrations) in the initial electronic ground state on the valence orbital momentum profiles of furan has been theoretically investigated using two different approaches. The first of these approaches employs the principles of Born-Oppenheimer molecular dynamics, whereas the so-called harmonic analytical quantum mechanical approach resorts to an analytical decomposition of contributions arising from quantized harmonic vibrational eigenstates. In spite of their intrinsic differences, the two approaches enable consistent insights into the electron momentum distributions inferred from new measurements employing electron momentum spectroscopy and an electron impact energy of 1.2 keV. Both approaches point out in particular an appreciable influence of a few specific molecular vibrations of A 1 symmetry on the 9a 1 momentum profile, which can be unravelled from considerations on the symmetry characteristics of orbitals and their energy spacing

Recent applications and current trends in Cultural Heritage Science using synchrotron-based Fourier transform infrared micro-spectroscopy

Science.gov (United States)

Cotte, Marine; Dumas, Paul; Taniguchi, Yoko; Checroun, Emilie; Walter, Philippe; Susini, Jean

2009-09-01

Synchrotron-based Fourier transform infrared micro-spectroscopy (SR-FTIR) is one of the emerging techniques increasingly employed for Cultural Heritage analytical science. Such a technique combines the assets of FTIR spectroscopy (namely, the identification of molecular groups in various environments: organic/inorganic, crystallized/amorphous, solid/liquid/gas), with the extra potential of chemical imaging (localization of components + easier data treatment thanks to geographical correlations) and the properties of the synchrotron source (namely, high brightness, offering high data quality even with reduced dwell time and reduced spot size). This technique can be applied to nearly all kind of materials found in museum objects, going from hard materials, like metals, to soft materials, like paper, and passing through hybrid materials such as paintings and bones. The purpose is usually the identification of complex compositions in tiny, heterogeneous samples. Recent applications are reviewed in this article, together with the fundamental aspects of the infrared synchrotron source which are leading to such improvements in analytical capabilities. A recent example from the ancient Buddhist paintings from Bamiyan is detailed. Emphasis is made on the true potential offered at such large scale facilities in combining SR-FTIR microscopy with other synchrotron-based micro-imaging techniques. To cite this article: M. Cotte et al., C. R. Physique 10 (2009).

Investigation of the molecular conformations of ethanol using electron momentum spectroscopy

International Nuclear Information System (INIS)

Ning, C G; Luo, Z H; Huang, Y R; Liu, K; Zhang, S F; Deng, J K; Hajgato, B; Morini, F; Deleuze, M S

2008-01-01

The valence electronic structure and momentum-space electron density distributions of ethanol have been investigated with our newly constructed high-resolution electron momentum spectrometer. The measurements are compared to thermally averaged simulations based on Kohn-Sham (B3LYP) orbital densities as well as one-particle Green's function calculations of ionization spectra and Dyson orbital densities, assuming Boltzmann's statistical distribution of the molecular structure over the two energy minima defining the anti and gauche conformers. One-electron ionization energies and momentum distributions in the outer-valence region were found to be highly dependent upon the molecular conformation. Calculated momentum distributions indeed very sensitively reflect the distortions and topological changes that molecular orbitals undergo due to the internal rotation of the hydroxyl group, and thereby exhibit variations which can be traced experimentally. The B3LYP model Kohn-Sham orbital densities are overall in good agreement with the experimental distributions, and closely resemble benchmark ADC(3) Dyson orbital densities. Both approaches fail to quantitatively reproduce the experimental momentum distributions characterizing the highest occupied molecular orbital. Since electron momentum spectroscopy measurements at various electron impact energies indicate that the plane wave impulse approximation is valid, this discrepancy between theory and experiment is tentatively ascribed to thermal disorder, i.e. large-amplitude and thermally induced dynamical distortions of the molecular structure in the gas phase

Real-time reflectance-difference spectroscopy of GaAs molecular beam epitaxy homoepitaxial growth

Directory of Open Access Journals (Sweden)

A. Lastras-Martínez

2014-03-01

Full Text Available We report on real time-resolved Reflectance-difference (RD spectroscopy of GaAs(001 grown by molecular beam epitaxy, with a time-resolution of 500 ms per spectrum within the 2.3–4.0 eV photon energy range. Through the analysis of transient RD spectra we demonstrated that RD line shapes are comprised of two components with different physical origins and determined their evolution during growth. Such components were ascribed to the subsurface strain induced by surface reconstruction and to surface stoichiometry. Results reported in this paper render RD spectroscopy as a powerful tool for the study of fundamental processes during the epitaxial growth of zincblende semiconductors.

Towards Breath Gas Analysis Based on Millimeter-Wave Molecular Spectroscopy

Science.gov (United States)

Rothbart, Nick; Hübers, Heinz-Wilhelm; Schmalz, Klaus; Borngräber, Johannes; Kissinger, Dietmar

2018-03-01

Breath gas analysis is a promising non-invasive tool for medical diagnosis as there are thousands of Volatile Organic Compounds (VOCs) in human breath that can be used as health monitoring markers. Millimeter-wave/terahertz molecular spectroscopy is highly suitable for breath gas analysis due to unique fingerprint spectra of many VOCs in that frequency range. We present our recent work on sensor systems for gas spectroscopy based on integrated transmitters (TX) and receivers (RX) fabricated in IHP's 0.13 μm SiGe BiCMOS technology. For a single-band system, spectroscopic measurements and beam profiles are presented. The frequency is tuned by direct voltage-frequency tuning and by a fractional-n PLL, respectively. The spectroscopic system includes a folded gas absorption cell with gas pre-concentration abilities demonstrating the detection of a 50 ppm mixture of ethanol in ambient air corresponding to a minimum detectable concentration of 260 ppb. Finally, the design of a 3-band system covering frequencies from 225 to 273 GHz is introduced.

Report of the workshop on accelerator-based atomic and molecular science

International Nuclear Information System (INIS)

Meyerhof, W.E.

1981-01-01

This Workshop, held in New London, NH on July 27-30, 1980, had a registration of 43, representing an estimated one-third of all principal investigators in the United States in this research subfield. The workshop was organized into 5 working groups for the purpose of (1) identifying some vital physics problems which experimental and theoretical atomic and molecular science can address with current and projected techniques; (2) establishing facilities and equipment needs required to realize solutions to these problems; (3) formulating suggestions for a coherent national policy concerning this discipline; (4) assessing and projecting the manpower situation; and (5) evaluating the relations of this interdisciplinary science to other fields. Recommedations deal with equipment and operating costs for small accelerator laboratories, especially at universities; instrumentation of ion beam lines dedicated to atomic and molecular science at some large accelerators; development of low-velocity, high charge-state ion sources; synchrotron light sources; improvement or replacement of tandem van de Graaff accelerators; high-energy beam lines for atomic physics; the needs for postdoctoral support in this subfield; new accelerator development; need for representatives from atomic and molecular science on program committees for large national accelerator facilities; and the contributions the field can make to applied physics problems

Molecular subgroups of medulloblastoma identification using noninvasive magnetic resonance spectroscopy.

Science.gov (United States)

Blüml, Stefan; Margol, Ashley S; Sposto, Richard; Kennedy, Rebekah J; Robison, Nathan J; Vali, Marzieh; Hung, Long T; Muthugounder, Sakunthala; Finlay, Jonathan L; Erdreich-Epstein, Anat; Gilles, Floyd H; Judkins, Alexander R; Krieger, Mark D; Dhall, Girish; Nelson, Marvin D; Asgharzadeh, Shahab

2016-01-01

Medulloblastomas in children can be categorized into 4 molecular subgroups with differing clinical characteristics, such that subgroup determination aids in prognostication and risk-adaptive treatment strategies. Magnetic resonance spectroscopy (MRS) is a widely available, noninvasive tool that is used to determine the metabolic characteristics of tumors and provide diagnostic information without the need for tumor tissue. In this study, we investigated the hypothesis that metabolite concentrations measured by MRS would differ between molecular subgroups of medulloblastoma and allow accurate subgroup determination. MRS was used to measure metabolites in medulloblastomas across molecular subgroups (SHH = 12, Groups 3/4 = 17, WNT = 1). Levels of 14 metabolites were analyzed to determine those that were the most discriminant for medulloblastoma subgroups in order to construct a multivariable classifier for distinguishing between combined Group 3/4 and SHH tumors. Medulloblastomas across molecular subgroups revealed distinct spectral features. Group 3 and Group 4 tumors demonstrated metabolic profiles with readily detectable taurine, lower levels of lipids, and high levels of creatine. SHH tumors showed prominent choline and lipid with low levels of creatine and little or no evidence of taurine. A 5-metabolite subgroup classifier inclusive of creatine, myo-inositol, taurine, aspartate, and lipid 13a was developed that could discriminate between Group 3/4 and SHH medulloblastomas with excellent accuracy (cross-validated area under the curve [AUC] = 0.88). The data show that medulloblastomas of Group 3/4 differ metabolically as measured using MRS when compared with SHH molecular subgroups. MRS is a useful and accurate tool to determine medulloblastoma molecular subgroups. © The Author(s) 2015. Published by Oxford University Press on behalf of the Society for Neuro-Oncology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Environmental and Molecular Science Laboratory Arrow

Energy Technology Data Exchange (ETDEWEB)

2016-06-24

Arrows is a software package that combines NWChem, SQL and NOSQL databases, email, and social networks (e.g. Twitter, Tumblr) that simplifies molecular and materials modeling and makes these modeling capabilities accessible to all scientists and engineers. EMSL Arrows is very simple to use. The user just emails chemical reactions to arrows@emsl.pnnl.gov and then an email is sent back with thermodynamic, reaction pathway (kinetic), spectroscopy, and other results. EMSL Arrows parses the email and then searches the database for the compounds in the reactions. If a compound isn't there, an NWChem calculation is setup and submitted to calculate it. Once the calculation is finished the results are entered into the database and then results are emailed back.

Probing molecular interactions in bone biomaterials: Through molecular dynamics and Fourier transform infrared spectroscopy

International Nuclear Information System (INIS)

Bhowmik, Rahul; Katti, Kalpana S.; Verma, Devendra; Katti, Dinesh R.

2007-01-01

Polymer-hydroxyapatite (HAP) composites are widely investigated for their potential use as bone replacement materials. The molecular interactions at mineral polymer interface are known to have significant role of mechanical response of the composite system. Modeling interactions between such dissimilar molecules using molecular dynamics (MD) is an area of current interest. Molecular dynamics studies require potential function or force field parameters. Some force fields are described in literature that represents the structure of hydroxyapatite reasonably well. Yet, the applicability of these force fields for studying the interaction between dissimilar materials (such as mineral and polymer) is limited, as there is no accurate representation of polymer in these force fields. We have obtained the parameters of consistent valence force field (CVFF) for monoclinic hydroxyapatite. Validation of parameters was done by comparing the computationally obtained unit cell parameters, vibrational spectra and atomic distances with XRD and FTIR experiments. Using the obtained parameters of HAP, and available parameters of polymer (polyacrylic acid), interaction study was performed with MD simulations. The MD simulations showed that several hydrogen bonds may form between HAP and polyacrylic acid depending upon the exposed surface of HAP. Also there are some favourable planes of HAP where polyacrylic acid is most likely to attach. We have also simulated the mineralization of HAP using a 'synthetic biomineralization'. These modeling studies are supported by photoacoustic spectroscopy experiments on both porous and non porous composite samples for potential joint replacement and bone tissue engineering applications

Gas-Phase Molecular Dynamics: Theoretical Studies in Spectroscopy and Chemical Dynamics

Energy Technology Data Exchange (ETDEWEB)

Yu, H.G.; Muckerman, J.T.

2010-06-01

The goal of this program is the development and application of computational methods for studying chemical reaction dynamics and molecular spectroscopy in the gas phase. We are interested in developing rigorous quantum dynamics algorithms for small polyatomic systems and in implementing approximate approaches for complex ones. Particular focus is on the dynamics and kinetics of chemical reactions and on the rovibrational spectra of species involved in combustion processes. This research also explores the potential energy surfaces of these systems of interest using state-of-the-art quantum chemistry methods.

Atomic and molecular data for optical stellar spectroscopy

International Nuclear Information System (INIS)

Heiter, U; Lind, K; Barklem, P S; Asplund, M; Bergemann, M; Magrini, L; Masseron, T; Mikolaitis, Š; Pickering, J C; Ruffoni, M P

2015-01-01

High-precision spectroscopy of large stellar samples plays a crucial role for several topical issues in astrophysics. Examples include studying the chemical structure and evolution of the Milky Way Galaxy, tracing the origin of chemical elements, and characterizing planetary host stars. Data are accumulating from instruments that obtain high-quality spectra of stars in the ultraviolet, optical and infrared wavelength regions on a routine basis. These instruments are located at ground-based 2–10 m class telescopes around the world, in addition to the spectrographs with unique capabilities available at the Hubble Space Telescope. The interpretation of these spectra requires high-quality transition data for numerous species, in particular neutral and singly ionized atoms, and di- or triatomic molecules. We rely heavily on the continuous efforts of laboratory astrophysics groups that produce and improve the relevant experimental and theoretical atomic and molecular data. The compilation of the best available data is facilitated by databases and electronic infrastructures such as the NIST Atomic Spectra Database, the VALD database, or the Virtual Atomic and Molecular Data Centre. We illustrate the current status of atomic data for optical stellar spectra with the example of the Gaia-ESO Public Spectroscopic Survey. Data sources for 35 chemical elements were reviewed in an effort to construct a line list for a homogeneous abundance analysis of up to 10 5 stars. (paper)

Atomic and molecular data for optical stellar spectroscopy

Science.gov (United States)

Heiter, U.; Lind, K.; Asplund, M.; Barklem, P. S.; Bergemann, M.; Magrini, L.; Masseron, T.; Mikolaitis, Š.; Pickering, J. C.; Ruffoni, M. P.

2015-05-01

High-precision spectroscopy of large stellar samples plays a crucial role for several topical issues in astrophysics. Examples include studying the chemical structure and evolution of the Milky Way Galaxy, tracing the origin of chemical elements, and characterizing planetary host stars. Data are accumulating from instruments that obtain high-quality spectra of stars in the ultraviolet, optical and infrared wavelength regions on a routine basis. These instruments are located at ground-based 2-10 m class telescopes around the world, in addition to the spectrographs with unique capabilities available at the Hubble Space Telescope. The interpretation of these spectra requires high-quality transition data for numerous species, in particular neutral and singly ionized atoms, and di- or triatomic molecules. We rely heavily on the continuous efforts of laboratory astrophysics groups that produce and improve the relevant experimental and theoretical atomic and molecular data. The compilation of the best available data is facilitated by databases and electronic infrastructures such as the NIST Atomic Spectra Database, the VALD database, or the Virtual Atomic and Molecular Data Centre. We illustrate the current status of atomic data for optical stellar spectra with the example of the Gaia-ESO Public Spectroscopic Survey. Data sources for 35 chemical elements were reviewed in an effort to construct a line list for a homogeneous abundance analysis of up to 105 stars.

The contribution of solid-state NMR spectroscopy to understanding biomineralization: Atomic and molecular structure of bone

Science.gov (United States)

Duer, Melinda J.

2015-04-01

Solid-state NMR spectroscopy has had a major impact on our understanding of the structure of mineralized tissues, in particular bone. Bone exemplifies the organic-inorganic composite structure inherent in mineralized tissues. The organic component of the extracellular matrix in bone is primarily composed of ordered fibrils of collagen triple-helical molecules, in which the inorganic component, calcium phosphate particles, composed of stacks of mineral platelets, are arranged around the fibrils. This perspective argues that key factors in our current structural model of bone mineral have come about through NMR spectroscopy and have yielded the primary information on how the mineral particles interface and bind with the underlying organic matrix. The structure of collagen within the organic matrix of bone or any other structural tissue has yet to be determined, but here too, this perspective shows there has been real progress made through application of solid-state NMR spectroscopy in conjunction with other techniques. In particular, NMR spectroscopy has highlighted the fact that even within these structural proteins, there is considerable dynamics, which suggests that one should be cautious when using inherently static structural models, such as those arising from X-ray diffraction analyses, to gain insight into molecular roles. It is clear that the NMR approach is still in its infancy in this area, and that we can expect many more developments in the future, particularly in understanding the molecular mechanisms of bone diseases and ageing.

Molecular orbitals for properties and spectroscopies

Energy Technology Data Exchange (ETDEWEB)

Robert, Vincent [Laboratoire de Chimie Quantique, Institut de Chimie, Université de Strasbourg, 1 rue Blaise Pascal 67000 Strasbourg-France (France); Domingo, Alex [Quantum Chemistry and Physical Chemistry Celestijnenlaan 200f, 3001 Heverlee - Belgium (Belgium); Braunstein, Pierre; Danopoulos, Andreas; Monakhov, Kirill [Laboratoire de Chimie de Coordination, Institut de Chimie, Université de Strasbourg, 4 rue Blaise Pascal 67081 Strasbourg-France (France)

2015-12-31

The description and clarification of spectroscopies and properties goes through ab initio calculations. Wave function based calculations (CASSCF/CASPT2) are particularly appealing since they offer spectroscopic accuracy and means of interpretation. we performed such calculations to elucidate the origin of unusual structural changes and intramolecular electron transfer phenomenon. Based on optimized molecular orbitals and a reading of the multireference wave function, it is suggested that intimate interactions are likely to considerably modify the standard pictures. A so-called PIMA (polarization-induced metalâĹŠarene) interaction similar to the more familiar anion-π interaction is responsible for a significant deviation from sp{sup 3} geometry and an energetic stabilization of 50 kJ/mol in Cr(II) benzyl organometallic complexes. In a similar fashion, it is proposed that the energetic profile of the IVCT (inter valence charge transfer) exhibits strong similarities to the Marcus’ theory, suggesting a response behaviour of the ensemble of electrons as electron transfer occurs in Fe{sup 2+}/Fe{sup 3+} bimetallic compound. The electronic reorganization induced by the IVCT process accounts for 11.8 eV, a very large effect that reduces the transfer energy down to 0.89 eV, in very good agreement with experiments.

Integration of Molecular Pathology, Epidemiology, and Social Science for Global Precision Medicine

Science.gov (United States)

Nishi, Akihiro; Milner, Danny A; Giovannucci, Edward L.; Nishihara, Reiko; Tan, Andy S.; Kawachi, Ichiro; Ogino, Shuji

2015-01-01

Summary The precision medicine concept and the unique disease principle imply that each patient has unique pathogenic processes resulting from heterogeneous cellular genetic and epigenetic alterations, and interactions between cells (including immune cells) and exposures, including dietary, environmental, microbial, and lifestyle factors. As a core method field in population health science and medicine, epidemiology is a growing scientific discipline that can analyze disease risk factors, and develop statistical methodologies to maximize utilization of big data on populations and disease pathology. The evolving transdisciplinary field of molecular pathological epidemiology (MPE) can advance biomedical and health research by linking exposures to molecular pathologic signatures, enhancing causal inference, and identifying potential biomarkers for clinical impact. The MPE approach can be applied to any diseases, although it has been most commonly used in neoplastic diseases (including breast, lung and colorectal cancers) because of availability of various molecular diagnostic tests. However, use of state-of-the-art genomic, epigenomic and other omic technologies and expensive drugs in modern healthcare systems increases racial, ethnic and socioeconomic disparities. To address this, we propose to integrate molecular pathology, epidemiology, and social science. Social epidemiology integrates the latter two fields. The integrative social MPE model can embrace sociology, economics and precision medicine, address global health disparities and inequalities, and elucidate biological effects of social environments, behaviors, and networks. We foresee advancements of molecular medicine, including molecular diagnostics, biomedical imaging, and targeted therapeutics, which should benefit individuals in a global population, by means of an interdisciplinary approach of integrative MPE and social health science. PMID:26636627

Integration of molecular pathology, epidemiology and social science for global precision medicine.

Science.gov (United States)

Nishi, Akihiro; Milner, Danny A; Giovannucci, Edward L; Nishihara, Reiko; Tan, Andy S; Kawachi, Ichiro; Ogino, Shuji

2016-01-01

The precision medicine concept and the unique disease principle imply that each patient has unique pathogenic processes resulting from heterogeneous cellular genetic and epigenetic alterations and interactions between cells (including immune cells) and exposures, including dietary, environmental, microbial and lifestyle factors. As a core method field in population health science and medicine, epidemiology is a growing scientific discipline that can analyze disease risk factors and develop statistical methodologies to maximize utilization of big data on populations and disease pathology. The evolving transdisciplinary field of molecular pathological epidemiology (MPE) can advance biomedical and health research by linking exposures to molecular pathologic signatures, enhancing causal inference and identifying potential biomarkers for clinical impact. The MPE approach can be applied to any diseases, although it has been most commonly used in neoplastic diseases (including breast, lung and colorectal cancers) because of availability of various molecular diagnostic tests. However, use of state-of-the-art genomic, epigenomic and other omic technologies and expensive drugs in modern healthcare systems increases racial, ethnic and socioeconomic disparities. To address this, we propose to integrate molecular pathology, epidemiology and social science. Social epidemiology integrates the latter two fields. The integrative social MPE model can embrace sociology, economics and precision medicine, address global health disparities and inequalities, and elucidate biological effects of social environments, behaviors and networks. We foresee advancements of molecular medicine, including molecular diagnostics, biomedical imaging and targeted therapeutics, which should benefit individuals in a global population, by means of an interdisciplinary approach of integrative MPE and social health science.

New insights into heat induced structural changes of pectin methylesterase on fluorescence spectroscopy and molecular modeling basis

Science.gov (United States)

Nistor, Oana Viorela; Stănciuc, Nicoleta; Aprodu, Iuliana; Botez, Elisabeta

2014-07-01

Heat-induced structural changes of Aspergillus oryzae pectin methylesterase (PME) were studied by means of fluorescence spectroscopy and molecular modeling, whereas the functional enzyme stability was monitored by inactivation studies. The fluorescence spectroscopy experiments were performed at two pH value (4.5 and 7.0). At both pH values, the phase diagrams were linear, indicating the presence of two molecular species induced by thermal treatment. A red shift of 7 nm was observed at neutral pH by increasing temperature up to 60 °C, followed by a blue shift of 4 nm at 70 °C, suggesting significant conformational rearrangements. The quenching experiments using acrylamide and iodide demonstrate a more flexible conformation of enzyme with increasing temperature, especially at neutral pH. The experimental results were complemented with atomic level observations on PME model behavior after performing molecular dynamics simulations at different temperatures. The inactivation kinetics of PME in buffer solutions was fitted using a first-order kinetics model, resulting in activation energy of 241.4 ± 7.51 kJ mol-1.

Recent development of momentum density measurement of polyatomics by molecular (e,2e) spectroscopy

International Nuclear Information System (INIS)

Leung, K.T.

1996-01-01

The use of coincidence techniques to study molecular electron collisions has enabled detailed investigation of collision dynamics and development of electron scattering theories. This has in turn facilitated powerful applications in studying electron-impact ionization phenomena using the so-called (e,2e) technique. Of particular interest is the use of the triple differential cross section for modelling ionic-state-specific electronic wavefunction density in momentum space. To date, detailed electronic structural information of well over sixty atomic and molecular systems have been obtained by this method. In the past five years, there has also been intense development in the application of (e,2e) spectroscopy to study larger molecular systems and condensed matter. This paper will review the recent progress made in this field, with a special focus on the development of momentum density measurement of open-quotes largeclose quotes molecular aggregates, oligomers and bio-molecules examined in this laboratory and elsewhere

Molecular ion photofragment spectroscopy

International Nuclear Information System (INIS)

Bustamente, S.W.

1983-11-01

A new molecular ion photofragment spectrometer is described which features a supersonic molecular beam ion source and a radio frequency octapole ion trap interaction region. This unique combination allows several techniques to be applied to the problem of detecting a photon absorption event of a molecular ion. In particular, it may be possible to obtain low resolution survey spectra of exotic molecular ions by using a direct vibrational predissociation process, or by using other more indirect detection methods. The use of the spectrometer is demonstrated by measuring the lifetime of the O 2 + ( 4 π/sub u/) metastable state which is found to consist of two main components: the 4 π/sub 5/2/ and 4 π/sub -1/2/ spin components having a long lifetime (approx. 129 ms) and the 4 π/sub 3/2/ and 4 π/sub 1/2/ spin components having a short lifetime (approx. 6 ms)

On selection rules in vibrational and rotational molecular spectroscopy

International Nuclear Information System (INIS)

Guichardet, A.

1986-01-01

The aim of this work is a rigorous proof of the Selection Rules in Molecular Spectroscopy (Vibration and Rotation). To get this we give mathematically rigorous definitions of the (tensor) transition operators, in this case the electric dipole moment; this is done, firstly by considering the molecule as a set of point atomic kernels performing arbitrary motions, secondly by limiting ourselves either to infinitesimal vibration motions, or to arbitrary rotation motions. Then the selection rules follow from an abstract formulation of the Wigner-Eckart theorem. In a last paragraph we discuss the problem of separating vibration and rotation motions; very simple ideas from Differential Geometry, linked with the ''slice theorem'', allow us to define the relative speeds, the solid motions speeds, the Coriolis energies and the moving Eckart frames [fr

Mid-infrared, long wave infrared (4-12 μm) molecular emission signatures from pharmaceuticals using laser-induced breakdown spectroscopy (LIBS).

Science.gov (United States)

Yang, Clayton S-C; Brown, Ei E; Kumi-Barimah, Eric; Hommerich, Uwe H; Jin, Feng; Trivedi, Sudhir B; Samuels, Alan C; Snyder, A Peter

2014-01-01

In an effort to augment the atomic emission spectra of conventional laser-induced breakdown spectroscopy (LIBS) and to provide an increase in selectivity, mid-wave to long-wave infrared (IR), LIBS studies were performed on several organic pharmaceuticals. Laser-induced breakdown spectroscopy signature molecular emissions of target organic compounds are observed for the first time in the IR fingerprint spectral region between 4-12 μm. The IR emission spectra of select organic pharmaceuticals closely correlate with their respective standard Fourier transform infrared spectra. Intact and/or fragment sample molecular species evidently survive the LIBS event. The combination of atomic emission signatures derived from conventional ultraviolet-visible-near-infrared LIBS with fingerprints of intact molecular entities determined from IR LIBS promises to be a powerful tool for chemical detection.

Study of atomic and molecular emission spectra of Sr by laser induced breakdown spectroscopy (LIBS).

Science.gov (United States)

Bhatt, Chet R; Alfarraj, Bader; Ayyalasomayajula, Krishna K; Ghany, Charles; Yueh, Fang Y; Singh, Jagdish P

2015-12-01

Laser Induced Breakdown Spectroscopy (LIBS) is an ideal analytical technique for in situ analysis of elemental composition. We have performed a comparative study of the quantitative and qualitative analysis of atomic and molecular emission from LIBS spectra. In our experiments, a mixture of SrCl2 and Al2O3 in powder form was used as a sample. The atomic emission from Sr and molecular emission from SrCl and SrO observed in LIBS spectra were analyzed. The optimum laser energies, gate delays, and gate widths for selected atomic lines and molecular bands were determined from spectra recorded at various experimental parameters. These optimum experimental conditions were used to collect calibration data, and the calibration curves were used to predict the Sr concentration. Limits of detection (LODs) for selected atomic and molecular emission spectra were determined.

Investigating the binding behaviour of two avidin-based testosterone binders using molecular recognition force spectroscopy.

Science.gov (United States)

Rangl, Martina; Leitner, Michael; Riihimäki, Tiina; Lehtonen, Soili; Hytönen, Vesa P; Gruber, Hermann J; Kulomaa, Markku; Hinterdorfer, Peter; Ebner, Andreas

2014-02-01

Molecular recognition force spectroscopy, a biosensing atomic force microscopy technique allows to characterise the dissociation of ligand-receptor complexes at the molecular level. Here, we used molecular recognition force spectroscopy to study the binding capability of recently developed testosterone binders. The two avidin-based proteins called sbAvd-1 and sbAvd-2 are expected to bind both testosterone and biotin but differ in their binding behaviour towards these ligands. To explore the ligand binding and dissociation energy landscape of these proteins, we tethered biotin or testosterone to the atomic force microscopy probe while the testosterone-binding protein was immobilized on the surface. Repeated formation and rupture of the ligand-receptor complex at different pulling velocities allowed determination of the loading rate dependence of the complex-rupturing force. In this way, we obtained the molecular dissociation rate (k(off)) and energy landscape distances (x(β)) of the four possible complexes: sbAvd-1-biotin, sbAvd-1-testosterone, sbAvd-2-biotin and sbAvd-2-testosterone. It was found that the kinetic off-rates for both proteins and both ligands are similar. In contrast, the x(β) values, as well as the probability of complex formations, varied considerably. In addition, competitive binding experiments with biotin and testosterone in solution differ significantly for the two testosterone-binding proteins, implying a decreased cross-reactivity of sbAvd-2. Unravelling the binding behaviour of the investigated testosterone-binding proteins is expected to improve their usability for possible sensing applications. Copyright © 2014 John Wiley & Sons, Ltd.

Molecular Gastronomy: A Food Fad or an Interface for Science-based Cooking?

NARCIS (Netherlands)

Linden, van der E.; McClements, D.J.; Ubbink, J.

2008-01-01

A review is given over the field of molecular gastronomy and its relation to science and cooking. We begin with a brief history of the field of molecular gastronomy, the definition of the term itself, and the current controversy surrounding this term. We then highlight the distinction between

The Environmental and Molecular Sciences Laboratory project -- Continuous evolution in leadership

International Nuclear Information System (INIS)

Knutson, D.E.; McClusky, J.K.

1994-10-01

The Environmental and Molecular Sciences Laboratory (EMSL) construction project at Pacific Northwest Laboratory (PNL) in Richland, Washington, is a $230M Major Systems Acquisition for the US Department of Energy (DOE). The completed laboratory will be a national user facility that provides unparalleled capabilities for scientists involved in environmental molecular science research. This project, approved for construction by the Secretary of Energy in October 1993, is underway. The United States is embarking on an environmental cleanup effort that dwarfs previous scientific enterprise. Using current best available technology, the projected costs of cleaning up the tens of thousands of toxic waste sites, including DOE sites, is estimated to exceed one trillion dollars. The present state of scientific knowledge regarding the effects of exogenous chemicals on human biology is very limited. Long term environmental research at the molecular level is needed to resolve the concerns, and form the building blocks for a structure of cost effective process improvement and regulatory reform

The Environmental and Molecular Sciences Laboratory project -- Continuous evolution in leadership

Energy Technology Data Exchange (ETDEWEB)

Knutson, D.E.; McClusky, J.K.

1994-10-01

The Environmental and Molecular Sciences Laboratory (EMSL) construction project at Pacific Northwest Laboratory (PNL) in Richland, Washington, is a $230M Major Systems Acquisition for the US Department of Energy (DOE). The completed laboratory will be a national user facility that provides unparalleled capabilities for scientists involved in environmental molecular science research. This project, approved for construction by the Secretary of Energy in October 1993, is underway. The United States is embarking on an environmental cleanup effort that dwarfs previous scientific enterprise. Using current best available technology, the projected costs of cleaning up the tens of thousands of toxic waste sites, including DOE sites, is estimated to exceed one trillion dollars. The present state of scientific knowledge regarding the effects of exogenous chemicals on human biology is very limited. Long term environmental research at the molecular level is needed to resolve the concerns, and form the building blocks for a structure of cost effective process improvement and regulatory reform.

Atomic and molecular photoelectron and Auger-electron-spectroscopy studies using synchrotron radiation

International Nuclear Information System (INIS)

Southworth, S.H.

1982-01-01

Electron spectroscopy, combined with synchrotron radiation, was used to measure the angular distributions of photoelectrons and Auger electrons from atoms and molecules as functions of photon energy. The branching ratios and partial cross sections were also measured in certain cases. By comparison with theoretical calculations, the experimental results are interpreted in terms of the characteristic electronic structure and ionization dynamics of the atomic or molecular sample. The time structure of the synchrotron radiation source was used to record time-of-flight (TOF) spectra of the ejected electrons. The double-angle-TOF method for the measurement of photoelectron angular distributions is discussed. This technique offers the advantages of increased electron collection efficiency and the elimination of certain systematic errors. An electron spectroscopy study of inner-shell photoexcitation and ionization of Xe, photoelectron angular distributions from H 2 and D 2 , and photoionization cross sections and photoelectron asymmetries of the valence orbitals of NO are reported

Molecular metal catalysts on supports: organometallic chemistry meets surface science.

Science.gov (United States)

Serna, Pedro; Gates, Bruce C

2014-08-19

Recent advances in the synthesis and characterization of small, essentially molecular metal complexes and metal clusters on support surfaces have brought new insights to catalysis and point the way to systematic catalyst design. We summarize recent work unraveling effects of key design variables of site-isolated catalysts: the metal, metal nuclearity, support, and other ligands on the metals, also considering catalysts with separate, complementary functions on supports. The catalysts were synthesized with the goal of structural simplicity and uniformity to facilitate incisive characterization. Thus, they are essentially molecular species bonded to porous supports chosen for their high degree of uniformity; the supports are crystalline aluminosilicates (zeolites) and MgO. The catalytic species are synthesized in reactions of organometallic precursors with the support surfaces; the precursors include M(L)2(acetylacetonate)1-2, with M = Ru, Rh, Ir, or Au and the ligands L = C2H4, CO, or CH3. Os3(CO)12 and Ir4(CO)12 are used as precursors of supported metal clusters, and some such catalysts are made by ship-in-a-bottle syntheses to trap the clusters in zeolite cages. The simplicity and uniformity of the supported catalysts facilitate precise structure determinations, even in reactive atmospheres and during catalysis. The methods of characterizing catalysts in reactive atmospheres include infrared (IR), extended X-ray absorption fine structure (EXAFS), X-ray absorption near edge structure (XANES), and nuclear magnetic resonance (NMR) spectroscopies, and complementary methods include density functional theory and atomic-resolution aberration-corrected scanning transmission electron microscopy for imaging of individual metal atoms. IR, NMR, XANES, and microscopy data demonstrate the high degrees of uniformity of well-prepared supported species. The characterizations determine the compositions of surface metal complexes and clusters, including the ligands and the metal

Building a Collaboratory in Environmental and Molecular Science

Energy Technology Data Exchange (ETDEWEB)

Kouzes, R.T.; Myers, J.D.; Devaney, D.M.; Dunning, T.H.; Wise, J.A.

1994-03-01

A Collaboratory is a meta-laboratory that spans multiple geographical areas with collaborators interacting via electronic means. Collaboratories are designed to enable close ties between scientists in a given research area, promote collaborations involving scientists in diverse areas, accelerate the development and dissemination of basic knowledge, and minimize the time-lag between discovery and application. PNL is developing the concept of an Environmental and Molecular Sciences Collaboratory (EMSC) as a natural evolution of the EMSL project. The goal of the EMSC is to increase the efficiency of research and reduce the time required to implement new environmental remediation and preservation technologies. The EMSC will leverage the resources (intellectual and physical) of the EMSL by making them more accessible to remote collaborators as well as by making the resources of remote sites available to local researchers. It will provide a common set of computer hardware and software tools to support remote collaboration, a key step in establishing a collaborative culture for scientists in the theoretical, computational, and experimental molecular sciences across the nation. In short, the EMSC will establish and support an `electronic community of scientists researching and developing innovative environmental preservation and restoration technologies.

Building a Collaboratory in Environmental and Molecular Science

International Nuclear Information System (INIS)

Kouzes, R.T.; Myers, J.D.; Devaney, D.M.; Dunning, T.H.; Wise, J.A.

1994-03-01

A Collaboratory is a meta-laboratory that spans multiple geographical areas with collaborators interacting via electronic means. Collaboratories are designed to enable close ties between scientists in a given research area, promote collaborations involving scientists in diverse areas, accelerate the development and dissemination of basic knowledge, and minimize the time-lag between discovery and application. PNL is developing the concept of an Environmental and Molecular Sciences Collaboratory (EMSC) as a natural evolution of the EMSL project. The goal of the EMSC is to increase the efficiency of research and reduce the time required to implement new environmental remediation and preservation technologies. The EMSC will leverage the resources (intellectual and physical) of the EMSL by making them more accessible to remote collaborators as well as by making the resources of remote sites available to local researchers. It will provide a common set of computer hardware and software tools to support remote collaboration, a key step in establishing a collaborative culture for scientists in the theoretical, computational, and experimental molecular sciences across the nation. In short, the EMSC will establish and support an 'electronic community of scientists researching and developing innovative environmental preservation and restoration technologies

Vibrations of bioionic liquids by ab initio molecular dynamics and vibrational spectroscopy.

Science.gov (United States)

Tanzi, Luana; Benassi, Paola; Nardone, Michele; Ramondo, Fabio

2014-12-26

Density functional theory and vibrational spectroscopy are used to investigate a class of bioionic liquids consisting of a choline cation and carboxylate anions. Through quantum mechanical studies of motionless ion pairs and molecular dynamics of small portions of the liquid, we have characterized important structural features of the ionic liquid. Hydrogen bonding produces stable ion pairs in the liquid and induces vibrational features of the carboxylate groups comparable with experimental results. Infrared and Raman spectra of liquids have been measured, and main bands have been assigned on the basis of theoretical spectra.

Combined spectroscopies and molecular docking approach to characterizing the binding interaction of enalapril with bovine serum albumin.

Science.gov (United States)

Pan, Dong-Qi; Jiang, Min; Liu, Ting-Ting; Wang, Qi; Shi, Jie-Hua

2017-06-01

The binding interaction between bovine serum albumin (BSA) and enalapril (ENPL) at the imitated physiological conditions (pH = 7.4) was investigated using UV-vis absorption spectroscopy (UV-vis), fluorescence emission spectroscopy (FES), synchronous fluorescence spectroscopy (SFS), Fourier transform infrared spectroscopy (FT-IR), circular dichroism (CD) and molecular docking methods. It can be deduced from the experimental results from the steady-state fluorescence spectroscopic titration that the intrinsic BSA fluorescence quenching mechanism induced by ENPL is static quenching, based on the decrease in the BSA quenching constants in the presence of ENPL with increase in temperature and BSA quenching rates >10 10  L mol -1  sec -1 . This result indicates that the ENPL-BSA complex is formed through an intermolecular interaction of ENPL with BSA. The main bonding forces for interaction of BSA and ENPL are van der Waal's forces and hydrogen bonding interaction based on negative values of Gibbs free energy change (ΔG 0 ), enthalpic change (ΔH 0 ) and entropic change (ΔS 0 ). The binding of ENPL with BSA is an enthalpy-driven process due to |ΔH°| > |TΔS°| in the binding process. The results of competitive binding experiments and molecular docking confirm that ENPL binds in BSA sub-domain IIA (site I) and results in a slight change in BSA conformation, but BSA still retains its α-helical secondary structure. Copyright © 2016 John Wiley & Sons, Ltd.

Molecular line parameters for the atmospheric trace molecule spectroscopy experiment

Science.gov (United States)

Brown, L. R.; Farmer, C. B.; Toth, R. A.; Rinsland, Curtis P.

1987-01-01

During its first mission in 1985 onboard Spacelab 3, the ATMOS (atmospheric trace molecule spectroscopy) instrument, a high speed Fourier transform spectrometer, produced a large number of high resolution infrared solar absorption spectra recorded in the occultation mode. The analysis and interpretation of these data in terms of composition, chemistry, and dynamics of the earth's upper atmosphere required good knowledge of the molecular line parameters for those species giving rise to the absorptions in the atmospheric spectra. This paper describes the spectroscopic line parameter database compiled for the ATMOS experiment and referenced in other papers describing ATMOS results. With over 400,000 entries, the linelist catalogs parameters of 46 minor and trace species in the 1-10,000/cm region.

Binding interaction of ramipril with bovine serum albumin (BSA): Insights from multi-spectroscopy and molecular docking methods.

Science.gov (United States)

Shi, Jie-Hua; Pan, Dong-Qi; Jiang, Min; Liu, Ting-Ting; Wang, Qi

2016-11-01

The binding interaction between a typical angiotensin-converting enzyme inhibitor (ACEI), ramipril, and a transport protein, bovine serum albumin (BSA), was studied in vitro using UV-vis absorption spectroscopy, steady-state fluorescence spectroscopic titration, synchronous fluorescence spectroscopy, three dimensional fluorescence spectroscopy, circular dichroism and molecular docking under the imitated physiological conditions (pH=7.4). The experimental results suggested that the intrinsic fluorescence of BSA was quenched by ramipril thought a static quenching mechanism, indicating that the stable ramipril-BSA complex was formed by the intermolecular interaction. The number of binding sites (n) and binding constant of ramipril-BSA complex were about 1 and 3.50×10 4 M -1 at 298K, respectively, suggesting that there was stronger binding interaction of ramipril with BSA. The thermodynamic parameters together with molecular docking study revealed that both van der Waal's forces and hydrogen bonding interaction dominated the formation of the ramipril-BSA complex and the binding interaction of BSA with ramipril is enthalpy-driven processes due to |ΔH°|>|TΔS°| and ΔG°<0. The spatial distance between ramipril and BSA was calculated to be 3.56nm based on Förster's non-radiative energy transfer theory. The results of the competitive displacement experiments and molecular docking confirmed that ramipril inserted into the subdomain IIA (site I) of BSA, resulting in a slight change in the conformation of BSA but BSA still retained its secondary structure α-helicity. Copyright © 2016 Elsevier B.V. All rights reserved.

Optical Spectroscopy

DEFF Research Database (Denmark)

Thyrhaug, Erling

The work presented in this thesis is broadly concerned with how complexation reactions and molecular motion can be characterized with the standard techniques in optical spectroscopy. The thesis aims to show a relatively broad range of methods for probing physico-chemical properties in fluorophore...... information about chemical equilibria, kinetics and molecular motion by monitoring changes in optical properties of the system. The five presented research projects are largely unrelated to each other both in aim and in what property is probed, however they are all connected in that they are fluorophore...... reactions by optical spectroscopy. In project 1 simple steady-state absorption and fluorescence spectroscopy is used to determine the stoichiometries and equilibrium constants in the inclusion complex formation between cyclodextrins and derivatives of the water-insoluble oligo(phenylene vinylene) in aqueous...

Scientific data management in the environmental molecular sciences laboratory

Energy Technology Data Exchange (ETDEWEB)

Bernard, P.R.; Keller, T.L.

1995-09-01

The Environmental Molecular Sciences Laboratory (EMSL) is currently under construction at Pacific Northwest Laboratory (PNL) for the U.S. Department of Energy (DOE). This laboratory will be used for molecular and environmental sciences research to identify comprehensive solutions to DOE`s environmental problems. Major facilities within the EMSL include the Molecular Sciences Computing Facility (MSCF), a laser-surface dynamics laboratory, a high-field nuclear magnetic resonance (NMR) laboratory, and a mass spectrometry laboratory. The EMSL is scheduled to open early in 1997 and will house about 260 resident and visiting scientists. It is anticipated that at least six (6) terabytes of data will be archived in the first year of operation. An object-oriented database management system (OODBMS) and a mass storage system will be integrated to provide an intelligent, automated mechanism to manage data. The resulting system, called the DataBase Computer System (DBCS), will provide total scientific data management capabilities to EMSL users. A prototype mass storage system based on the National Storage Laboratory`s (NSL) UniTree has been procured and is in limited use. This system consists of two independent hierarchies of storage devices. One hierarchy of lower capacity, slower speed devices provides support for smaller files transferred over the Fiber Distributed Data Interface (FDDI) network. Also part of the system is a second hierarchy of higher capacity, higher speed devices that will be used to support high performance clients (e.g., a large scale parallel processor). The ObjectStore OODBMS will be used to manage metadata for archived datasets, maintain relationships between archived datasets, and -hold small, duplicate subsets of archived datasets (i.e., derivative data). The interim system is called DBCS, Phase 0 (DBCS-0). The production system for the EMSL, DBCS Phase 1 (DBCS-1), will be procured and installed in the summer of 1996.

Spectrally selective molecular doped solids: spectroscopy, photophysics and their application to ultrafast optical pulse processing

International Nuclear Information System (INIS)

Galaup, Jean-Pierre

2005-01-01

The persistent spectral hole-burning (PSHB) phenomenon observed in molecular doped polymers cooled down to liquid helium temperatures allows the engraving of spectral structures in the inhomogeneous absorption profile of the material. This phenomenon known since 1974 has became a fruitful field for the study of the intimacy of complex molecular systems in the solid state, revealing high-resolution spectroscopy, photophysics, photochemistry and dynamics of molecular doped amorphous media, organic as well as inorganic. A PSHB molecular doped solid can be programmed in spectral domain and therefore, it can be converted in an optical processor capable to achieve user-defined optical functions. Some aspects of this field are illustrated in the present paper. An application is presented where a naphthalocyanine doped polymer film is used in a demonstrative experiment to prove that temporal aberration free re-compression of ultra-short light pulses is feasible. Perspectives for the coherent control of light fields or photochemical processes are also evoked

Analysis of sub-nano spaces by positron annihilation spectroscopy

International Nuclear Information System (INIS)

Jean, Y.C.; Liu, J.; Huang, C.M.; Dai, G.H.; Yuan, J.P.

1994-01-01

Positron annihilation spectroscopy (PAS) has been realized to be a novel and potentially powerful tool to evolve the open spaces in the range 1-20 angstrom in molecular systems. Due to the repulsive force between the positron (the anti-particle of the electron) and the cores, annihilation signals are solely contributed from the open spaces, such as vacancies, holes, and voids in the molecular subtracts under study. By further developing two PAS techniques, positron lifetime (PAL), and angular correlation (ACAR), the authors are able to obtain useful and important information of: hole sizes, distributions, hole fractions, and anisotropic structures at sub-nano scales. Applications of PAS to chemical analysis, surface chemistry of inner pores, and polymer sciences are discussed

Molecular tools for bathing water assessment in Europe: Balancing social science research with a rapidly developing environmental science evidence-base.

Science.gov (United States)

Oliver, David M; Hanley, Nick D; van Niekerk, Melanie; Kay, David; Heathwaite, A Louise; Rabinovici, Sharyl J M; Kinzelman, Julie L; Fleming, Lora E; Porter, Jonathan; Shaikh, Sabina; Fish, Rob; Chilton, Sue; Hewitt, Julie; Connolly, Elaine; Cummins, Andy; Glenk, Klaus; McPhail, Calum; McRory, Eric; McVittie, Alistair; Giles, Amanna; Roberts, Suzanne; Simpson, Katherine; Tinch, Dugald; Thairs, Ted; Avery, Lisa M; Vinten, Andy J A; Watts, Bill D; Quilliam, Richard S

2016-02-01

The use of molecular tools, principally qPCR, versus traditional culture-based methods for quantifying microbial parameters (e.g., Fecal Indicator Organisms) in bathing waters generates considerable ongoing debate at the science-policy interface. Advances in science have allowed the development and application of molecular biological methods for rapid (~2 h) quantification of microbial pollution in bathing and recreational waters. In contrast, culture-based methods can take between 18 and 96 h for sample processing. Thus, molecular tools offer an opportunity to provide a more meaningful statement of microbial risk to water-users by providing near-real-time information enabling potentially more informed decision-making with regard to water-based activities. However, complementary studies concerning the potential costs and benefits of adopting rapid methods as a regulatory tool are in short supply. We report on findings from an international Working Group that examined the breadth of social impacts, challenges, and research opportunities associated with the application of molecular tools to bathing water regulations.

Raman spectroscopy in high temperature chemistry

International Nuclear Information System (INIS)

Drake, M.C.; Rosenblatt, G.M.

1979-01-01

Raman spectroscopy (largely because of advances in laser and detector technology) is assuming a rapidly expanding role in many areas of research. This paper reviews the contribution of Raman spectroscopy in high temperature chemistry including molecular spectroscopy on static systems and gas diagnostic measurements on reactive systems. An important aspect of high temperature chemistry has been the identification and study of the new, and often unusual, gaseous molecules which form at high temperatures. Particularly important is the investigation of vibrational-rotational energy levels and electronic states which determine thermodynamic properties and describe chemical bonding. Some advantages and disadvantages of high temperature Raman spectrosocpy for molecular studies on static systems are compared: (1) Raman vs infrared; (2) gas-phase vs condensed in matries; and (3) atmospheric pressure Raman vs low pressure techniques, including mass spectroscopy, matrix isolation, and molecular beams. Raman studies on molecular properties of gases, melts, and surfaces are presented with emphasis on work not covered in previous reviews of high temperature and matrix isolation Raman spectroscopy

Raman spectroscopy in high temperature chemistry

International Nuclear Information System (INIS)

Drake, M.C.; Rosenblatt, G.M.

1979-01-01

Raman spectroscopy (largely because of advances in laser and detector technology) is assuming a rapidly expanding role in many areas of research. This paper reviews the contribution of Raman spectroscopy in high temperature chemistry including molecular spectroscopy on static systems and gas diagnostic measurements on reactive systems. An important aspect of high temperature chemistry has been the identification and study of the new, and often unusual, gaseous molecules which form at high temperatures. Particularly important is the investigation of vibrational-rotational energy levels and electronic states which determine thermodynamic properties and describe chemical bonding. Some advantages and disadvantages of high temperature Raman spectrosocpy for molecular studies on static systems are compared: (1) Raman vs infrared; (2) gas-phase vs condensed in matrices; and (3) atmospheric pressure Raman vs low pressure techniques, including mass spectroscopy, matrix isolation, and molecular beams. Raman studies on molecular properties of gases, melts, and surfaces are presented with emphasis on work not covered in previous reviews of high temperature and matrix isolation Raman spectroscopy

Environmental Molecular Sciences Laboratory Operations System: Version 4.0 - system requirements specification

Energy Technology Data Exchange (ETDEWEB)

Kashporenko, D.

1996-07-01

This document is intended to provide an operations standard for the Environmental Molecular Sciences Laboratory OPerations System (EMSL OPS). It is directed toward three primary audiences: (1) Environmental Molecular Sciences Laboratory (EMSL) facility and operations personnel; (2) laboratory line managers and staff; and (3) researchers, equipment operators, and laboratory users. It is also a statement of system requirements for software developers of EMSL OPS. The need for a finely tuned, superior research environment as provided by the US Department of Energy`s (DOE) Environmental Molecular Sciences Laboratory has never been greater. The abrupt end of the Cold War and the realignment of national priorities caused major US and competing overseas laboratories to reposition themselves in a highly competitive research marketplace. For a new laboratory such as the EMSL, this means coming into existence in a rapidly changing external environment. For any major laboratory, these changes create funding uncertainties and increasing global competition along with concomitant demands for higher standards of research product quality and innovation. While more laboratories are chasing fewer funding dollars, research ideas and proposals, especially for molecular-level research in the materials and biological sciences, are burgeoning. In such an economically constrained atmosphere, reduced costs, improved productivity, and strategic research project portfolio building become essential to establish and maintain any distinct competitive advantage. For EMSL, this environment and these demands require clear operational objectives, specific goals, and a well-crafted strategy. Specific goals will evolve and change with the evolution of the nature and definition of DOE`s environmental research needs. Hence, EMSL OPS is designed to facilitate migration of these changes with ease into every pertinent job function, creating a facile {open_quotes}learning organization.{close_quotes}

Development of time-resolved electron momentum spectroscopy. Toward real-time imaging of frontier electrons in molecular reactions

International Nuclear Information System (INIS)

Yamazaki, M.; Takahashi, M.

2016-01-01

This report will introduce a new experimental technique to readers, which we would like to propose towards advances in the field of molecular reaction dynamics. It is time-resolved electron momentum spectroscopy and aims to take in momentum space snapshots of the rapid change of molecular orbitals, which is the driving force behind any structural changes occurring in transient molecules. Following a description of the working principle of the technique, some preliminary result will be presented in order to illustrate the current performance of the apparatus. (author)

Matrix isolation FT-IR spectroscopy and molecular orbital study of sarcosine methyl ester

OpenAIRE

Gómez-Zavaglia, Andrea; Fausto, R.

2004-01-01

N-methylglycine methyl ester (sarcosine-Me) has been studied by matrix isolation FT-IR spectroscopy and molecular orbital calculations undertaken at the DFT/B3LYP and MP2 levels of theory with the 6-311++G(d,p) and 6-31++G(d,p) basis set, respectively. Twelve different conformers were located in the potential energy surface of the studied compound, with the ASC conformer being the ground conformational state. This form is analogous to the dimethylglycine methyl ester most stable conformer and...

Styrene oligomerization as a molecular probe reaction for zeolite acidity: a UV-Vis spectroscopy and DFT study

NARCIS (Netherlands)

Buurmans, I.L.C.; Pidko, E.A.; Groot, de J.M.; Stavitski, E.; Santen, van R.A.; Weckhuysen, B.M.

2010-01-01

A series of H-ZSM-5 crystallites with different framework Si/Al ratios was studied by analyzing the kinetics and reaction mechanism of the oligomerization of 4-fluorostyrene as molecular probe reaction for Brønsted acidity. The formation of carbocationic species was followed by UV-Vis spectroscopy.

Environmental Molecular Sciences Laboratory 2004 Annual Report

Energy Technology Data Exchange (ETDEWEB)

White, Julia C.

2005-04-17

This 2004 Annual Report describes the research and accomplishments of staff and users of the W.R. Wiley Environmental Molecular Sciences Laboratory (EMSL), located in Richland, Washington. EMSL is a multidisciplinary, national scientific user facility and research organization, operated by Pacific Northwest National Laboratory (PNNL) for the U.S. Department of Energy's Office of Biological and Environmental Research. The resources and opportunities within the facility are an outgrowth of the U.S. Department of Energy's (DOE) commitment to fundamental research for understanding and resolving environmental and other critical scientific issues.

First results from the high-brightness x-ray spectroscopy beamline at ALS

Energy Technology Data Exchange (ETDEWEB)

Perera, R.C.C.; Ng, W.; Jones, G. [Lawrence Berkeley National Lab., CA (United States)] [and others

1997-04-01

Beamline 9.3.1 at the Advanced Light Source (ALS) is a windowless beamline, covering the 1-6 keV photon-energy range, designed to achieve the goal of high brightness at the sample for use in the X-ray Atomic and Molecular Spectroscopy (XAMS) science, surface and interface science, biology and x-ray optical development programs at ALS. X-ray absorption and time of flight photo emission measurements in 2 - 5 keV photon energy in argon along with the flux, resolution, spot size and stability of the beamline will be discussed. Prospects for future XAMS measurements will also be presented.

Ultrafast spectroscopy on DNA-cleavage by endonuclease in molecular crowding.

Science.gov (United States)

Singh, Priya; Choudhury, Susobhan; Dutta, Shreyasi; Adhikari, Aniruddha; Bhattacharya, Siddhartha; Pal, Debasish; Pal, Samir Kumar

2017-10-01

The jam-packed intracellular environments differ the activity of a biological macromolecule from that in laboratory environments (in vitro) through a number of mechanisms called molecular crowding related to structure, function and dynamics of the macromolecule. Here, we have explored the structure, function and dynamics of a model enzyme protein DNase I in molecular crowing of polyethylene glycol (PEG; MW 3350). We have used steady state and picosecond resolved dynamics of a well-known intercalator ethidium bromide (EB) in a 20-mer double-stranded DNA (dsDNA) to monitor the DNA-cleavage by the enzyme in absence and presence PEG. We have also labelled the enzyme by a well-known fluorescent probe 8-anilino-1-naphthalenesulfonic acid ammonium salt (ANS) to study the molecular mechanism of the protein-DNA association through exited state relaxation of the probe in absence (dictated by polarity) and presence of EB in the DNA (dictated by Förster resonance energy transfer (FRET)). The overall and local structures of the protein in presence of PEG have been followed by circular dichroism and time resolved polarization gated spectroscopy respectively. The enhanced dynamical flexibility of protein in presence of PEG as revealed from excited state lifetime and polarization gated anisotropy of ANS has been correlated with the stronger DNA-binding for the higher nuclease activity. We have also used conventional experimental strategy of agarose gel electrophoresis to monitor DNA-cleavage and found consistent results of enhanced nuclease activities both on synthetic 20-mer oligonucleotide and long genomic DNA from calf thymus. Copyright © 2017 Elsevier B.V. All rights reserved.

Phospholipid Vesicles in Materials Science

Energy Technology Data Exchange (ETDEWEB)

Granick, Steve [Univ. of Illinois, Champaign, IL (United States)

2016-05-11

The objective of this research was to develop the science basis needed to deploy phospholipid vesicles as functional materials in energy contexts. Specifically, we sought to: (1) Develop an integrated molecular-level understanding of what determines their dynamical shape, spatial organization, and responsiveness to complex, time-varying environments; and (2) Develop understanding of their active transportation in crowded environments, which our preliminary measurements in cells suggest may hold design principles for targeting improved energy efficiency in new materials systems. The methods to do this largely involved fluorescence imaging and other spectroscopy involving single particles, vesicles, particles, DNA, and endosomes. An unexpected importance outcome was a new method to image light-emitting diodes during actual operation using super-resolution spectroscopy.

Gas-Phase Molecular Dynamics: Theoretical Studies In Spectroscopy and Chemical Dynamics

Energy Technology Data Exchange (ETDEWEB)

Yu H. G.; Muckerman, J.T.

2012-05-29

The main goal of this program is the development and application of computational methods for studying chemical reaction dynamics and molecular spectroscopy in the gas phase. We are interested in developing rigorous quantum dynamics algorithms for small polyatomic systems and in implementing approximate approaches for complex ones. Particular focus is on the dynamics and kinetics of chemical reactions and on the rovibrational spectra of species involved in combustion processes. This research also explores the potential energy surfaces of these systems of interest using state-of-the-art quantum chemistry methods, and extends them to understand some important properties of materials in condensed phases and interstellar medium as well as in combustion environments.

Molecular symmetry and spectroscopy

CERN Document Server

Bunker, Philip; Jensen, Per

2006-01-01

The first edition, by P.R. Bunker, published in 1979, remains the sole textbook that explains the use of the molecular symmetry group in understanding high resolution molecular spectra. Since 1979 there has been considerable progress in the field and a second edition is required; the original author has been joined in its writing by Per Jensen. The Material of the first edition has been reorganized and much has been added. The molecular symmetry group is now introduced early on, and the explanation of how to determine nuclear spin statistical weights has been consolidated in one chapter, after groups, symmetry groups, character tables and the Hamiltonian have been introduced. A description of the symmetry in the three-dimensional rotation group K(spatial), irreducible spherical tensor operators, and vector coupling coefficients is now included. The chapters on energy levels and selection rules contain a great deal of material that was not in the first edition (much of it was undiscovered in 1979), concerning ...

A preliminary exploration of the advanced molecular bio-sciences research center

International Nuclear Information System (INIS)

Yanai, Takanori; Yamada, Yutaka; Tanaka, Kimio; Yamagami, Mutsumi; Sota, Masahiro; Takemura, Tatsuo; Koyama, Kenji; Sato, Fumiaki

2001-01-01

Low dose and low dose rate radiation effects on lifespan, pathological changes, hemopoiesis and cytokine production in mice have been investigated in our laboratory. In the intermediate period of the investigation, an expert committee on radiation biology was organized. The purposes of the committee were to assess previous studies and advise on a future research plan for the Advanced Molecular Bio-Sciences Research Center (AMBIC). The committee emphasized the necessity of molecular research in radiation biology, and proposed the following five subjects: 1) molecular carcinogenesis by low dose radiation; 2) radiation effects on the immune and hemopoietic systems; 3) molecular mechanisms of hereditary effect; 4) noncancer diseases of low dose radiation, and 5) cellular mechanisms by low dose radiation. (author)

Molecular quantum dynamics. From theory to applications

International Nuclear Information System (INIS)

Gatti, Fabien

2014-01-01

An educational and accessible introduction to the field of molecular quantum dynamics. Illustrates the importance of the topic for broad areas of science: from astrophysics and the physics of the atmosphere, over elementary processes in chemistry, to biological processes. Presents chosen examples of striking applications, highlighting success stories, summarized by the internationally renowned experts. Including a foreword by Lorenz Cederbaum (University Heidelberg, Germany). This book focuses on current applications of molecular quantum dynamics. Examples from all main subjects in the field, presented by the internationally renowned experts, illustrate the importance of the domain. Recent success in helping to understand experimental observations in fields like heterogeneous catalysis, photochemistry, reactive scattering, optical spectroscopy, or femto- and attosecond chemistry and spectroscopy underline that nuclear quantum mechanical effects affect many areas of chemical and physical research. In contrast to standard quantum chemistry calculations, where the nuclei are treated classically, molecular quantum dynamics can cover quantum mechanical effects in their motion. Many examples, ranging from fundamental to applied problems, are known today that are impacted by nuclear quantum mechanical effects, including phenomena like tunneling, zero point energy effects, or non-adiabatic transitions. Being important to correctly understand many observations in chemical, organic and biological systems, or for the understanding of molecular spectroscopy, the range of applications covered in this book comprises broad areas of science: from astrophysics and the physics and chemistry of the atmosphere, over elementary processes in chemistry, to biological processes (such as the first steps of photosynthesis or vision). Nevertheless, many researchers refrain from entering this domain. The book ''Molecular Quantum Dynamics'' offers them an accessible introduction. Although the

Molecular quantum dynamics. From theory to applications

Energy Technology Data Exchange (ETDEWEB)

Gatti, Fabien (ed.) [Montpellier 2 Univ. (France). Inst. Charles Gerhardt - CNRS 5253

2014-09-01

An educational and accessible introduction to the field of molecular quantum dynamics. Illustrates the importance of the topic for broad areas of science: from astrophysics and the physics of the atmosphere, over elementary processes in chemistry, to biological processes. Presents chosen examples of striking applications, highlighting success stories, summarized by the internationally renowned experts. Including a foreword by Lorenz Cederbaum (University Heidelberg, Germany). This book focuses on current applications of molecular quantum dynamics. Examples from all main subjects in the field, presented by the internationally renowned experts, illustrate the importance of the domain. Recent success in helping to understand experimental observations in fields like heterogeneous catalysis, photochemistry, reactive scattering, optical spectroscopy, or femto- and attosecond chemistry and spectroscopy underline that nuclear quantum mechanical effects affect many areas of chemical and physical research. In contrast to standard quantum chemistry calculations, where the nuclei are treated classically, molecular quantum dynamics can cover quantum mechanical effects in their motion. Many examples, ranging from fundamental to applied problems, are known today that are impacted by nuclear quantum mechanical effects, including phenomena like tunneling, zero point energy effects, or non-adiabatic transitions. Being important to correctly understand many observations in chemical, organic and biological systems, or for the understanding of molecular spectroscopy, the range of applications covered in this book comprises broad areas of science: from astrophysics and the physics and chemistry of the atmosphere, over elementary processes in chemistry, to biological processes (such as the first steps of photosynthesis or vision). Nevertheless, many researchers refrain from entering this domain. The book ''Molecular Quantum Dynamics'' offers them an accessible

Announcing the International Journal of Molecular Sciences Junior Scientists Travel Awards 2016

Directory of Open Access Journals (Sweden)

International Journal of Molecular Sciences Editorial Office

2016-03-01

Full Text Available With the goal of recognizing outstanding contributions to the field of molecular sciences by early-career investigators, including assistant professors, postdoctoral students and PhD students, [...

Laboratory molecular spectroscopy

International Nuclear Information System (INIS)

Margolis, J.

1982-04-01

The precision required in making spectroscopic measurements is discussed. Remarks are directed specifically to vibration-rotation spectra rather than continuum absorptions. The ultimate precision that is required for line positions is related to the width of the lines which may be no narrower than the Doppler width. The spectroscopic methods considered are those which are of the most general value to the astronomers, those which acquire and can handle large volumes of spectra in digital form, or in a form which is compatible with computer analysis, and in a form which is at least internally consistent. The use of dye laser, grating instruments, and the most versatile instrument for laboratory spectroscopy, the Fourier transform spectrometer is discussed

Molecular catalysis science: Perspective on unifying the fields of catalysis.

Science.gov (United States)

Ye, Rong; Hurlburt, Tyler J; Sabyrov, Kairat; Alayoglu, Selim; Somorjai, Gabor A

2016-05-10

Colloidal chemistry is used to control the size, shape, morphology, and composition of metal nanoparticles. Model catalysts as such are applied to catalytic transformations in the three types of catalysts: heterogeneous, homogeneous, and enzymatic. Real-time dynamics of oxidation state, coordination, and bonding of nanoparticle catalysts are put under the microscope using surface techniques such as sum-frequency generation vibrational spectroscopy and ambient pressure X-ray photoelectron spectroscopy under catalytically relevant conditions. It was demonstrated that catalytic behavior and trends are strongly tied to oxidation state, the coordination number and crystallographic orientation of metal sites, and bonding and orientation of surface adsorbates. It was also found that catalytic performance can be tuned by carefully designing and fabricating catalysts from the bottom up. Homogeneous and heterogeneous catalysts, and likely enzymes, behave similarly at the molecular level. Unifying the fields of catalysis is the key to achieving the goal of 100% selectivity in catalysis.

Molecular biology in marine science: Scientific questions, technological approaches, and practical implications

Energy Technology Data Exchange (ETDEWEB)

NONE

1994-12-31

This report describes molecular techniques that could be invaluable in addressing process-oriented problems in the ocean sciences that have perplexed oceanographers for decades, such as understanding the basis for biogeochemical processes, recruitment processes, upper-ocean dynamics, biological impacts of global warming, and ecological impacts of human activities. The coupling of highly sophisticated methods, such as satellite remote sensing, which permits synoptic monitoring of chemical, physical, and biological parameters over large areas, with the power of modern molecular tools for ``ground truthing`` at small scales could allow scientists to address questions about marine organisms and the ocean in which they live that could not be answered previously. Clearly, the marine sciences are on the threshold of an exciting new frontier of scientific discovery and economic opportunity.

Fundamental studies of molecular multiphoton ionization

International Nuclear Information System (INIS)

Miller, J.C.; Compton, R.N.

1984-04-01

For several years the authors have performed fundamental studies of molecular multiphoton ionization (MPI). We will present a potpourri of techniques and results chosen to illustrate the interesting complexities of molecular MPI. Techniques used include time-of-flight mass spectroscopy, photoelectron spectroscopy, supersonic expansion cooling of molecular beams, harmonic generation, two-color laser MPI, and polarization spectroscopy. Whenever possible the relevance of these results to resonance ionization spectroscopy schemes will be delineated. 23 references, 10 figures

Cheminformatics Research at the Unilever Centre for Molecular Science Informatics Cambridge.

Science.gov (United States)

Fuchs, Julian E; Bender, Andreas; Glen, Robert C

2015-09-01

The Centre for Molecular Informatics, formerly Unilever Centre for Molecular Science Informatics (UCMSI), at the University of Cambridge is a world-leading driving force in the field of cheminformatics. Since its opening in 2000 more than 300 scientific articles have fundamentally changed the field of molecular informatics. The Centre has been a key player in promoting open chemical data and semantic access. Though mainly focussing on basic research, close collaborations with industrial partners ensured real world feedback and access to high quality molecular data. A variety of tools and standard protocols have been developed and are ubiquitous in the daily practice of cheminformatics. Here, we present a retrospective of cheminformatics research performed at the UCMSI, thereby highlighting historical and recent trends in the field as well as indicating future directions.

A preliminary exploration of Advanced Molecular Bio-Sciences Research Center

International Nuclear Information System (INIS)

Yamada, Yutaka; Yanai, Takanori; Onodera, Jun'ichi; Yamagami, Mutsumi; Sakata, Hiroshi; Sota, Masahiro; Takemura, Tatsuo; Koyama, Kenji; Sato, Fumiaki

2000-01-01

Low-dose and low-dose-rate radiation effects on life-span, pathological changes, hemopoiesis and cytokine production in experimental animals have been investigated in our laboratory. In the intermediate period of the investigation, an expert committee on radiation biology, which was composed of two task groups, was organized. The purposes of the committee were to assess of previous studies and plan future research for Advanced Molecular Bio-Sciences Research Center (AMBIC). In its report, the committee emphasized the necessity of molecular research in radiation biology and ecology, and proposed six subjects for the research: 1) Molecular carcinogenesis of low-dose radiation; 2) Radiation effects on the immune system and hemopoietic system; 3) Molecular mechanisms of hereditary effect; 4) Non cancer effect of low-dose radiation; 5) Gene targeting for ion transport system in plants; 6) Bioremediation with transgenic plant and bacteria. Exploration of the AMBIC project will continue under the committee's direction. (author)

The use of laser-induced breakdown spectroscopy for the determination of fluorine concentration in glass ionomer cement

Czech Academy of Sciences Publication Activity Database

Kratochvíl, T.; Pouzar, M.; Novotný, K.; Havránek, Vladimír; Černohorský, T.; Zvolská, M.

2013-01-01

Roč. 88, OCT (2013), s. 26-31 ISSN 0584-8547 Grant - others:GA ČR(CZ) GAP207/11/0555 Institutional support: RVO:61389005 Keywords : Fluorine * GIC * Laser-induced breakdown spectroscopy * Quantitative analysis Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 3.150, year: 2013 http://www.sciencedirect.com/science/article/pii/S0584854713002243#

Molecular science solving global problems

International Nuclear Information System (INIS)

Dunning, T.H. Jr.; Stults, B.R.

1995-01-01

From the late 1940s to the late 1980s, the Department of Energy (DOE) had a critical role in the Cold War. Many sites were built to contribute to the nation's nuclear weapons effort. However, not enough attention was paid to how the waste generated at these facilities should be handled. As a result, a number of sites fouled the soil around them or dumped low-level radioactive waste into nearby rivers. A DOE laboratory is under construction with a charter to help. Called the Environmental Molecular Sciences Laboratory (EMSL), this national user facility will be located at DOE's Pacific Northwest Laboratory (PNL) in Richland, WA. This laboratory has been funded by DOE and Congress to play a major role as the nation confronts the enormous challenge of reducing environmental and human risks from hundreds of government and industrial waste sites in an economically viable manner. The original proposal for the EMSL took a number of twists and turns on its way to its present form, but one thing remained constant: the belief that safe, permanent, cost-effective solutions to many of the country's environmental problems could be achieved only by multidisciplinary teams working to understand and control molecular processes. The processes of most concern are those that govern the transport and transformation of contaminants, the treatment and storage of high-level mixed wastes, and the risks those contaminants ultimately pose to workers and the public

The MIND PALACE: A Multi-Spectral Imaging and Spectroscopy Database for Planetary Science

Science.gov (United States)

Eshelman, E.; Doloboff, I.; Hara, E. K.; Uckert, K.; Sapers, H. M.; Abbey, W.; Beegle, L. W.; Bhartia, R.

2017-12-01

The Multi-Instrument Database (MIND) is the web-based home to a well-characterized set of analytical data collected by a suite of deep-UV fluorescence/Raman instruments built at the Jet Propulsion Laboratory (JPL). Samples derive from a growing body of planetary surface analogs, mineral and microbial standards, meteorites, spacecraft materials, and other astrobiologically relevant materials. In addition to deep-UV spectroscopy, datasets stored in MIND are obtained from a variety of analytical techniques obtained over multiple spatial and spectral scales including electron microscopy, optical microscopy, infrared spectroscopy, X-ray fluorescence, and direct fluorescence imaging. Multivariate statistical analysis techniques, primarily Principal Component Analysis (PCA), are used to guide interpretation of these large multi-analytical spectral datasets. Spatial co-referencing of integrated spectral/visual maps is performed using QGIS (geographic information system software). Georeferencing techniques transform individual instrument data maps into a layered co-registered data cube for analysis across spectral and spatial scales. The body of data in MIND is intended to serve as a permanent, reliable, and expanding database of deep-UV spectroscopy datasets generated by this unique suite of JPL-based instruments on samples of broad planetary science interest.

Structural analysis of molten Na2O-NaF-SiO2 system by Raman spectroscopy and molecular dynamics simulation

International Nuclear Information System (INIS)

Sasaki, Yasushi; Urata, Hidehiro; Ishii, Kuniyoshi

2003-01-01

To determine the effect of F ions on the structure of the molten alkali silicate systems, quenched Na 2 O-SiO 2 -NaF systems were investigated by Raman spectroscopy and molecular dynamics simulation. The systematic increase of 1100cm -1 band intensity in the Raman spectra of the silicate melts accompanying the replacement of O by F provides the evidence for concomitant polymerization of melts. From the molecular dynamics simulation, it was confirmed that most of substituted F was mainly coordinated to Na + ions but not Si 4+ ions at least up to 12.5 mol% of F ion content. A small amount of F was found to be coordinated to Si as a non-bridging ion from the molecular dynamics simulation, although there was no recognizable evidence from Raman Spectroscopy. These results were consistent with the mechanism in which F associated with otherwise network-modifying Na rather than with network-forming Si. Since F was associated to Na + ions, the replace of O ion by two F ions promote the polymerization of silicate melts. (author)

Frames of scientific evidence: How journalists represent the (un)certainty of molecular medicine in science television programs.

Science.gov (United States)

Ruhrmann, Georg; Guenther, Lars; Kessler, Sabrina Heike; Milde, Jutta

2015-08-01

For laypeople, media coverage of science on television is a gateway to scientific issues. Defining scientific evidence is central to the field of science, but there are still questions if news coverage of science represents scientific research findings as certain or uncertain. The framing approach is a suitable framework to classify different media representations; it is applied here to investigate the frames of scientific evidence in film clips (n=207) taken from science television programs. Molecular medicine is the domain of interest for this analysis, due to its high proportion of uncertain and conflicting research findings and risks. The results indicate that television clips vary in their coverage of scientific evidence of molecular medicine. Four frames were found: Scientific Uncertainty and Controversy, Scientifically Certain Data, Everyday Medical Risks, and Conflicting Scientific Evidence. They differ in their way of framing scientific evidence and risks of molecular medicine. © The Author(s) 2013.

Miniature Chemical Sensor Combining Molecular Recognition with Evanescent Wave Cavity Ring-Down Spectroscopy

International Nuclear Information System (INIS)

Pipino, Andrew C. R.; Meuse, Curtis W.

2002-01-01

To address the chemical sensing needs of DOE, a new class of chemical sensors is being developed that enables qualitative and quantitative, remote, real-time, optical diagnostics of chemical species in hazardous gas, liquid, and semi-solid phases by employing evanescent wave cavity ringdown spectroscopy (EW-CRDS). The sensitivity of EW-CRDS was demonstrated previously under Project No.60231. The objective of this project is to enhance the range of application and selectivity of the technique by combining EW-CRDS with refractive-index-sensitive nanoparticle optics, molecular recognition (MR) chemistry, and by utilizing the polarization-dependence of EW-CRDS. Research Progress and Implications

Interaction of Chelerythrine with Keyhole Limpet Hemocyanin: a Fluorescence Spectroscopy and Molecular Docking Study

Science.gov (United States)

Zhong, M.; Long, R. Q.; Wang, Y. H.; Chen, C. L.

2018-05-01

The quenching mechanism between chelerythrine (CHE) and keyhole limpet hemocyanin (KLH) was investigated using fluorescence spectroscopy and molecular docking. The experiments were conducted at three different temperatures (293, 298, and 303 K). The results revealed that the intrinsic fluorescence of KLH was strongly quenched by CHE through a static quenching mechanism. The thermodynamic parameters (ΔG, ΔH, and ΔS) of the interaction were calculated, indicating that the interaction between CHE and KLH was spontaneous and that van der Waals forces and hydrogen bond formation played major roles in the binding process. The intrinsic fluorescence of the tyrosine and tryptophan residues in KLH was studied by synchronous fluorescence, which suggested that CHE changed the conformation of KLH. Finally, molecular docking was used to obtain detailed information on the binding sites and binding affinities between CHE and KLH.

Surface vibrational spectroscopy

International Nuclear Information System (INIS)

Erskine, J.L.

1984-01-01

A brief review of recent studies which combine measurements of surface vibrational energies with lattice dynamical calculations is presented. These results suggest that surface vibrational spectroscopy offers interesting prospects for use as a molecular-level probe of surface geometry, adsorbate bond distances and molecular orientations

Molecular Science Research Center annual report

Energy Technology Data Exchange (ETDEWEB)

Knotek, M.L.

1991-01-01

The Chemical Structure and Dynamics group is studying chemical kinetics and reactions dynamics of terrestrial and atmospheric processes as well as the chemistry of complex waste forms and waste storage media. Staff are using new laser systems and surface-mapping techniques in combination with molecular clusters that mimic adsorbate/surface interactions. The Macromolecular Structure and Dynamics group is determining biomolecular structure/function relationships for processes the control the biological transformation of contaminants and the health effects of toxic substances. The Materials and Interfaces program is generating information needed to design and synthesize advanced materials for the analysis and separation of mixed chemical waste, the long-term storage of concentrated hazardous materials, and the development of chemical sensors for environmental monitoring of various organic and inorganic species. The Theory, Modeling, and Simulation group is developing detailed molecular-level descriptions of the chemical, physical, and biological processes in natural and contaminated systems. Researchers are using the full spectrum of computational techniques. The Computer and Information Sciences group is developing new approaches to handle vast amounts of data and to perform calculations for complex natural systems. The EMSL will contain a high-performance computing facility, ancillary computing laboratories, and high-speed data acquisition systems for all major research instruments.

Interdisciplinary research center devoted to molecular environmental science opens

Science.gov (United States)

Vaughan, David J.

In October, a new research center opened at the University of Manchester in the United Kingdom. The center is the product of over a decade of ground-breaking interdisciplinary research in the Earth and related biological and chemical sciences at the university The center also responds to the British governments policy of investing in research infrastructure at key universities.The Williamson Research Centre, the first of its kind in Britain and among the first worldwide, is devoted to the emerging field of molecular environmental science. This field also aims to bring about a revolution in understanding of our environment. Though it may be a less violent revolution than some, perhaps, its potential is high for developments that could affect us all.

Molecular environmental geochemistry

Science.gov (United States)

O'Day, Peggy A.

1999-05-01

The chemistry, mobility, and bioavailability of contaminant species in the natural environment are controlled by reactions that occur in and among solid, aqueous, and gas phases. These reactions are varied and complex, involving changes in chemical form and mass transfer among inorganic, organic, and biochemical species. The field of molecular environmental geochemistry seeks to apply spectroscopic and microscopic probes to the mechanistic understanding of environmentally relevant chemical processes, particularly those involving contaminants and Earth materials. In general, empirical geochemical models have been shown to lack uniqueness and adequate predictive capability, even in relatively simple systems. Molecular geochemical tools, when coupled with macroscopic measurements, can provide the level of chemical detail required for the credible extrapolation of contaminant reactivity and bioavailability over ranges of temperature, pressure, and composition. This review focuses on recent advances in the understanding of molecular chemistry and reaction mechanisms at mineral surfaces and mineral-fluid interfaces spurred by the application of new spectroscopies and microscopies. These methods, such as synchrotron X-ray absorption and scattering techniques, vibrational and resonance spectroscopies, and scanning probe microscopies, provide direct chemical information that can elucidate molecular mechanisms, including element speciation, ligand coordination and oxidation state, structural arrangement and crystallinity on different scales, and physical morphology and topography of surfaces. Nonvacuum techniques that allow examination of reactions in situ (i.e., with water or fluids present) and in real time provide direct links between molecular structure and reactivity and measurements of kinetic rates or thermodynamic properties. Applications of these diverse probes to laboratory model systems have provided fundamental insight into inorganic and organic reactions at

Beamline 9.0.1 - a high-resolution undulator beamline for gas-phase spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Bozek, J.D.; Heimann, P.A.; Mossessian, D. [Ernest Orlando Lawrence Berkeley National Lab., CA (United States)

1997-04-01

Beamline 9.0.1 at the Advanced Light Source is an undulator beamline with a Spherical Grating Monochromator (SGM) which provides very high resolution and flux over the photon energy range 20-320eV. The beamline has been used primarily by the atomic and molecular science community to conduct spectroscopy experiments using electron, ion and fluorescence photon detection. A description of the beamline and its performance will be provided in this abstract.

Handbook of Applied Solid State Spectroscopy

CERN Document Server

Vij, D. R

2006-01-01

Solid-State spectroscopy is a burgeoning field with applications in many branches of science, including physics, chemistry, biosciences, surface science, and materials science. Handbook of Applied Solid-State Spectroscopy brings together in one volume information about various spectroscopic techniques that is currently scattered in the literature of these disciplines. This concise yet comprehensive volume covers theory and applications of a broad range of spectroscopies, including NMR, NQR, EPR/ESR, ENDOR, scanning tunneling, acoustic resonance, FTIR, auger electron emission, x-ray photoelectron emission, luminescence, and optical polarization, and more. Emphasis is placed on fundamentals and current methods and procedures, together with the latest applications and developments in the field.

Surface-Enhanced Raman Spectroscopy

Indian Academy of Sciences (India)

Home; Journals; Resonance – Journal of Science Education; Volume 15; Issue 2. Surface-Enhanced Raman Spectroscopy - Recent Advancement of Raman Spectroscopy. Ujjal Kumar Sur. General Article Volume 15 Issue 2 February 2010 pp 154-164 ...

Real-time molecular imaging throughout the entire cell cycle by targeted plasmonic-enhanced Rayleigh/Raman spectroscopy.

Science.gov (United States)

Kang, Bin; Austin, Lauren A; El-Sayed, Mostafa A

2012-10-10

Due to their strong enhancement of scattered light, plasmonic nanoparticles have been utilized for various biological and medical applications. Here, we describe a new technique, Targeted Plasmonic-Enhanced Single-Cell Rayleigh/Raman Spectroscopy, to monitor the molecular changes of any cell-component, such as the nucleus, during the different phases of its full cell cycle by simultaneously recording its Rayleigh images and Raman vibration spectra in real-time. The analysis of the observed Raman DNA and protein peaks allowed the different phases of the cell cycle to be identified. This technique could be used for disease diagnostics and potentially improve our understanding of the molecular mechanisms of cellular functions such as division, death, signaling, and drug action.

Molecular forensic science of nuclear materials

International Nuclear Information System (INIS)

Wilkerson, Marianne Perry

2010-01-01

We are interested in applying our understanding of actinide chemical structure and bonding to broaden the suite of analytical tools available for nuclear forensic analyses. Uranium- and plutonium-oxide systems form under a variety of conditions, and these chemical species exhibit some of the most complex behavior of metal oxide systems known. No less intriguing is the ability of AnO 2 (An: U, Pu) to form non-stoichiometric species described as AnO 2+x . Environmental studies have shown the value of utilizing the chemical signatures of these actinide oxides materials to understand transport following release into the environment. Chemical speciation of actinide-oxide samples may also provide clues as to the age, source, process history, or transport of the material. The scientific challenge is to identify, measure and understand those aspects of speciation of actinide analytes that carry information about material origin and history most relevant to forensics. Here, we will describe our efforts in material synthesis and analytical methods development that we will use to provide the fundamental science required to characterize actinide oxide molecular structures for forensics science. Structural properties and initial results to measure structural variability of uranium oxide samples using synchrotron-based X-ray Absorption Fine Structure will be discussed.

A method for the direct measurement of electronic site populations in a molecular aggregate using two-dimensional electronic-vibrational spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Lewis, Nicholas H. C.; Dong, Hui; Oliver, Thomas A. A.; Fleming, Graham R., E-mail: grfleming@lbl.gov [Department of Chemistry, University of California, Berkeley, California 94720 (United States); Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Kavli Energy Nanosciences Institute at Berkeley, Berkeley, California 94720 (United States)

2015-09-28

Two dimensional electronic spectroscopy has proved to be a valuable experimental technique to reveal electronic excitation dynamics in photosynthetic pigment-protein complexes, nanoscale semiconductors, organic photovoltaic materials, and many other types of systems. It does not, however, provide direct information concerning the spatial structure and dynamics of excitons. 2D infrared spectroscopy has become a widely used tool for studying structural dynamics but is incapable of directly providing information concerning electronic excited states. 2D electronic-vibrational (2DEV) spectroscopy provides a link between these domains, directly connecting the electronic excitation with the vibrational structure of the system under study. In this work, we derive response functions for the 2DEV spectrum of a molecular dimer and propose a method by which 2DEV spectra could be used to directly measure the electronic site populations as a function of time following the initial electronic excitation. We present results from the response function simulations which show that our proposed approach is substantially valid. This method provides, to our knowledge, the first direct experimental method for measuring the electronic excited state dynamics in the spatial domain, on the molecular scale.

Molecular electronics: some views on transport junctions and beyond.

Science.gov (United States)

Joachim, Christian; Ratner, Mark A

2005-06-21

The field of molecular electronics comprises a fundamental set of issues concerning the electronic response of molecules as parts of a mesoscopic structure and a technology-facing area of science. We will overview some important aspects of these subfields. The most advanced ideas in the field involve the use of molecules as individual logic or memory units and are broadly based on using the quantum state space of the molecule. Current work in molecular electronics usually addresses molecular junction transport, where the molecule acts as a barrier for incoming electrons: This is the fundamental Landauer idea of "conduction as scattering" generalized to molecular junction structures. Another point of view in terms of superexchange as a guiding mechanism for coherent electron transfer through the molecular bridge is discussed. Molecules generally exhibit relatively strong vibronic coupling. The last section of this overview focuses on vibronic effects, including inelastic electron tunneling spectroscopy, hysteresis in junction charge transport, and negative differential resistance in molecular transport junctions.

Rabi oscillations and rapid-passage effects in the molecular-beam CO2-laser Stark spectroscopy of CH3F

International Nuclear Information System (INIS)

Adam, A.G.; Gough, T.E.; Isenor, N.R.; Scoles, G.

1985-01-01

sub-Doppler molecular-beam laser Stark spectroscopy has been employed to produce high-contrast Rabi oscillations in the ν 3 band of CH 3 F. By varying the intensity of the cw CO 2 laser, up to five complete oscillations were observed before the phenomenon was washed out by rapid-passage effects and damping mechanisms. Besides being useful in clarifying key features of coherent ir molecular-beam spectroscopy, the observation of Rabi oscillations provides one of the most accurate means of directly measuring transition dipole moments. Analysis of the present data on three rovibrational transitions, Q(1,1) -1reverse arrow0, P(1,0) 0reverse arrow0, and R(1,1) 0reverse arrow1, has yielded a rotationless transition dipole moment of 0.21 +- 0.01 D for the ν 3 = 1reverse arrow0 vibration. This result is in agreement with values estimated from both band-intensity and absorption-coefficient data in the literature

Communication: High pressure specific heat spectroscopy reveals simple relaxation behavior of glass forming molecular liquid

DEFF Research Database (Denmark)

Roed, Lisa Anita; Niss, Kristine; Jakobsen, Bo

2015-01-01

The frequency dependent specific heat has been measured under pressure for the molecular glass forming liquid 5-polyphenyl-4-ether in the viscous regime close to the glass transition. The temperature and pressure dependences of the characteristic time scale associated with the specific heat...... is compared to the equivalent time scale from dielectric spectroscopy performed under identical conditions. It is shown that the ratio between the two time scales is independent of both temperature and pressure. This observation is non-trivial and demonstrates the existence of specially simple molecular...... liquids in which different physical relaxation processes are both as function of temperature and pressure/density governed by the same underlying “inner clock.” Furthermore, the results are discussed in terms of the recent conjecture that van der Waals liquids, like the measuredliquid, comply...

Study on the interaction between tabersonine and human serum albumin by optical spectroscopy and molecular modeling methods

Energy Technology Data Exchange (ETDEWEB)

Jiang Hua; Chen, Rongrong [Department of Biology, College of Life Science and Technology, Jinan University, Guangzhou 510632 (China); Pu Hanlin, E-mail: tphl@jnu.edu.cn [Department of Biology, College of Life Science and Technology, Jinan University, Guangzhou 510632 (China)

2012-03-15

The mechanism of interaction between tabersonine (TAB) and human serum albumin (HSA) was investigated by the methods of fluorescence spectroscopy, UV-vis absorption spectroscopy and molecular modeling under simulative physiological conditions. Results obtained from analysis of fluorescence spectrum and fluorescence intensity indicated that TAB has a strong ability to quench the intrinsic fluorescence of HSA through a static quenching procedure. The binding site number n and apparent binding constant K{sub a}, corresponding thermodynamic parameters {Delta}G, {Delta}H and {Delta}S at different temperatures were calculated. The distance r between donor (human serum albumin) and acceptor (tabersonine) was obtained according to the Foerster theory of non-radiation energy transfer. The effect of common ions on binding constant was also investigated. The synchronous fluorescence and three-dimensional fluorescence spectra were used to investigate the structural change of HSA molecules with addition of TAB. Furthermore, the study of molecular modeling indicated that TAB could bind to the site I of HSA and hydrophobic interaction was the major acting force, which was in agreement with the binding mode study. - Highlights: Black-Right-Pointing-Pointer Fluorescence study of the mechanism of interaction between tabersonine and HSA. Black-Right-Pointing-Pointer The binding parameters and thermodynamic parameters were calculated. Black-Right-Pointing-Pointer The distance r was obtained and common ions effects was investigated. Black-Right-Pointing-Pointer Conformation of HSA and its molecular modeling was analyzed.

Systems biology for molecular life sciences and its impact in biomedicine.

Science.gov (United States)

Medina, Miguel Ángel

2013-03-01

Modern systems biology is already contributing to a radical transformation of molecular life sciences and biomedicine, and it is expected to have a real impact in the clinical setting in the next years. In this review, the emergence of systems biology is contextualized with a historic overview, and its present state is depicted. The present and expected future contribution of systems biology to the development of molecular medicine is underscored. Concerning the present situation, this review includes a reflection on the "inflation" of biological data and the urgent need for tools and procedures to make hidden information emerge. Descriptions of the impact of networks and models and the available resources and tools for applying them in systems biology approaches to molecular medicine are provided as well. The actual current impact of systems biology in molecular medicine is illustrated, reviewing two cases, namely, those of systems pharmacology and cancer systems biology. Finally, some of the expected contributions of systems biology to the immediate future of molecular medicine are commented.

Broadband Rotational Spectroscopy

Science.gov (United States)

Pate, Brooks

2014-06-01

The past decade has seen several major technology advances in electronics operating at microwave frequencies making it possible to develop a new generation of spectrometers for molecular rotational spectroscopy. High-speed digital electronics, both arbitrary waveform generators and digitizers, continue on a Moore's Law-like development cycle that started around 1993 with device bandwidth doubling about every 36 months. These enabling technologies were the key to designing chirped-pulse Fourier transform microwave (CP-FTMW) spectrometers which offer significant sensitivity enhancements for broadband spectrum acquisition in molecular rotational spectroscopy. A special feature of the chirped-pulse spectrometer design is that it is easily implemented at low frequency (below 8 GHz) where Balle-Flygare type spectrometers with Fabry-Perot cavity designs become technologically challenging due to the mirror size requirements. The capabilities of CP-FTMW spectrometers for studies of molecular structure will be illustrated by the collaborative research effort we have been a part of to determine the structures of water clusters - a project which has identified clusters up to the pentadecamer. A second technology trend that impacts molecular rotational spectroscopy is the development of high power, solid state sources in the mm-wave/THz regions. Results from the field of mm-wave chirped-pulse Fourier transform spectroscopy will be described with an emphasis on new problems in chemical dynamics and analytical chemistry that these methods can tackle. The third (and potentially most important) technological trend is the reduction of microwave components to chip level using monolithic microwave integrated circuits (MMIC) - a technology driven by an enormous mass market in communications. Some recent advances in rotational spectrometer designs that incorporate low-cost components will be highlighted. The challenge to the high-resolution spectroscopy community - as posed by Frank De

Periodontitis diagnostics using resonance Raman spectroscopy on saliva

Science.gov (United States)

Gonchukov, S.; Sukhinina, A.; Bakhmutov, D.; Biryukova, T.; Tsvetkov, M.; Bagratashvily, V.

2013-07-01

In view of its wealth of molecular information, Raman spectroscopy has been the subject of active biomedical research. The aim of this work is Raman spectroscopy (RS) application for the determination of molecular biomarkers in saliva with the objective of early periodontitis detection. As was shown in our previous study, carotenoids contained in saliva can be molecular fingerprint information for the periodontitis level. It is shown here that the carotenoid RS lines at wavenumbers of 1156 and 1524 cm-1 can be easily detected and serve as reliable biomarkers of periodontitis using resonance Raman spectroscopy of dry saliva.

Periodontitis diagnostics using resonance Raman spectroscopy on saliva

International Nuclear Information System (INIS)

Gonchukov, S; Sukhinina, A; Bakhmutov, D; Biryukova, T; Tsvetkov, M; Bagratashvily, V

2013-01-01

In view of its wealth of molecular information, Raman spectroscopy has been the subject of active biomedical research. The aim of this work is Raman spectroscopy (RS) application for the determination of molecular biomarkers in saliva with the objective of early periodontitis detection. As was shown in our previous study, carotenoids contained in saliva can be molecular fingerprint information for the periodontitis level. It is shown here that the carotenoid RS lines at wavenumbers of 1156 and 1524 cm −1 can be easily detected and serve as reliable biomarkers of periodontitis using resonance Raman spectroscopy of dry saliva. (letter)

Positron annihilation lifetime spectroscopy (PALS): a probe for molecular organisation in self-assembled biomimetic systems.

Science.gov (United States)

Fong, Celesta; Dong, Aurelia W; Hill, Anita J; Boyd, Ben J; Drummond, Calum J

2015-07-21

Positron annihilation lifetime spectroscopy (PALS) has been shown to be highly sensitive to conformational, structural and microenvironmental transformations arising from subtle geometric changes in molecular geometry in self-assembling biomimetic systems. The ortho-positronium (oPs) may be considered an active probe that can provide information on intrinsic packing and mobility within low molecular weight solids, viscous liquids, and soft matter systems. In this perspective we provide a critical overview of the literature in this field, including the evolution of analysis software and experimental protocols with commentary upon the practical utility of PALS. In particular, we discuss how PALS can provide unique insight into the macroscopic transport properties of several porous biomembrane-like nanostructures and suggest how this insight may provide information on the release of drugs from these matrices to aid in developing therapeutic interventions. We discuss the potentially exciting and fruitful application of this technique to membrane dynamics, diffusion and permeability. We propose that PALS can provide novel molecular level information that is complementary to conventional characterisation techniques.

Photoelectron spectroscopy on the charge reorganization energy and small polaron binding energy of molecular film

Energy Technology Data Exchange (ETDEWEB)

Kera, Satoshi, E-mail: kera@ims.ac.jp [Institute for Molecular Science, Myodaiji, Okazaki 444-8585 (Japan); Department of Nanomaterial Science, Graduate School of Advanced Integration Science, Chiba University, Inage-ku, Chiba 263-8522 (Japan); Ueno, Nobuo [Department of Nanomaterial Science, Graduate School of Advanced Integration Science, Chiba University, Inage-ku, Chiba 263-8522 (Japan)

2015-10-01

Understanding of electron-phonon coupling as well as intermolecular interaction is required to discuss the mobility of charge carrier in functional molecular solids. This article summarizes recent progress in direct measurements of valence hole-vibration coupling in ultrathin films of organic semiconductors by using ultraviolet photoelectron spectroscopy (UPS). The experimental study of hole-vibration coupling of the highest occupied molecular orbital (HOMO) state in ordered monolayer film by UPS is essential to comprehend hole-hopping transport and small-polaron related transport in organic semiconductors. Only careful measurements can attain the high-resolution spectra and provide key parameters in hole-transport dynamics, namely the charge reorganization energy and small polaron binding energy. Analyses methods of the UPS HOMO fine feature and resulting charge reorganization energy and small polaron binding energy are described for pentacene and perfluoropentacene films. Difference between thin-film and gas-phase results is discussed by using newly measured high-quality gas-phase spectra of pentacene. Methodology for achieving high-resolution UPS measurements for molecular films is also described.

Vibrational Spectroscopy as a Promising Toolbox for Analyzing Functionalized Ceramic Membranes.

Science.gov (United States)

Kiefer, Johannes; Bartels, Julia; Kroll, Stephen; Rezwan, Kurosch

2018-01-01

Ceramic materials find use in many fields including the life sciences and environmental engineering. For example, ceramic membranes have shown to be promising filters for water treatment and virus retention. The analysis of such materials, however, remains challenging. In the present study, the potential of three vibrational spectroscopic methods for characterizing functionalized ceramic membranes for water treatment is evaluated. For this purpose, Raman scattering, infrared (IR) absorption, and solvent infrared spectroscopy (SIRS) were employed. The data were analyzed with respect to spectral changes as well as using principal component analysis (PCA). The Raman spectra allow an unambiguous discrimination of the sample types. The IR spectra do not change systematically with functionalization state of the material. Solvent infrared spectroscopy allows a systematic distinction and enables studying the molecular interactions between the membrane surface and the solvent.

Moessbauer spectroscopy. Tutorial book

International Nuclear Information System (INIS)

Yoshida, Yutaka; Langouche, Guido

2013-01-01

First textbook on Moessbauer Spectroscopy covering the complete field. Offers a concise introduction to all aspects of Moessbauer spectroscopy by the leading experts in the field. Tutorials on Moessbauer Spectroscopy. Since the discovery of the Moessbauer Effect many excellent books have been published for researchers and for doctoral and master level students. However, there appears to be no textbook available for final year bachelor students, nor for people working in industry who have received only basic courses in classical mechanics, electromagnetism, quantum mechanics, chemistry and materials science. The challenge of this book is to give an introduction to Moessbauer Spectroscopy for this level. The ultimate goal of this book is to give this audience not only a scientific introduction to the technique, but also to demonstrate in an attractive way the power of Moessbauer Spectroscopy in many fields of science, in order to create interest among the readers in joining the community of Moessbauer spectroscopists. This is particularly important at times where in many Moessbauer laboratories succession is at stake.

Molecular physics. Theoretical principles and experimental methods

International Nuclear Information System (INIS)

Demtroeder, W.

2005-01-01

This advanced textbook comprehensively explains important principles of diatomic and polyatomic molecules and their spectra in two separate, distinct parts. The first part concentrates on the theoretical aspects of molecular physics, whereas the second part of the book covers experimental techniques, i.e. laser, Fourier, NMR, and ESR spectroscopies, used in the fields of physics, chemistry, biolog, and material science. Appropriate for undergraduate and graduate students in physics and chemistry with a knowledge of atomic physics and familiar with the basics of quantum mechanics. From the contents: - Electronic States of Molecules, - Rotation, Oscillation and Potential Curves of Diatomic Molecules, - The Spectra of Diatomic Molecules, - Molecule Symmetries and Group Theory, - Rotation and Oscillations of Polyatomic Molecules, - Electronic States of Polyatomic Molecules, - The Spectra of Polyatomic Molecules, - Collapse of the Born-Oppenheimer-Approximation, Disturbances in Molecular Spectra, - Molecules in Disturbing Fields, - Van-der-Waals-Molecules and Cluster, - Experimental Techniques in Molecular Physics. (orig.)

Direct correlation of charge transfer absorption with molecular donor:acceptor interfacial area via photothermal deflection spectroscopy

KAUST Repository

Domingo, Ester

2015-04-09

We show that the Charge Transfer (CT) absorption signal in bulk-heterojunction (BHJ) solar cell blends, measured by photothermal deflection spectroscopy (PDS), is directly proportional to the density of molecular donor/acceptor interfaces. Since the optical transitions from ground state to the interfacial CT state are weakly allowed at photon energies below the optical gap of both donor and acceptor, we can exploit the use of this sensitive linear absorption spectroscopy for such quantification. Moreover, we determine the absolute molar extinction coefficient of the CT transition for an archetypical polymer-fullerene interface. The latter is ~100 times lower than the extinction coefficient of the donor chromophore involved, allowing us to experimentally estimate the transition dipole moment (0.3 D) and the electronic coupling between ground state and CT state to be on the order of 30 meV.

Overview of the Joint NASA ISRO Imaging Spectroscopy Science Campaign in India

Science.gov (United States)

Green, R. O.; Bhattacharya, B. K.; Eastwood, M. L.; Saxena, M.; Thompson, D. R.; Sadasivarao, B.

2016-12-01

In the period from December 2015 to March 2016 the Airborne Visible-Infrared Imaging Spectrometer Next Generation (AVIRIS-NG) was deployed to India for a joint NASA ISRO science campaign. This campaign was conceived to provide first of their kind high fidelity imaging spectroscopy measurements of a diverse set of Asian environments for science and applications research. During this campaign measurements were acquired for 57 high priority sites that have objectives spanning: snow/ice of the Himalaya; coastal habitats and water quality; mangrove forests; soils; dry and humid forests; hydrocarbon alteration; mineralogy; agriculture; urban materials; atmospheric properties; and calibration/validation. Measurements from the campaign have been processed to at-instrument spectral radiance and atmospherically corrected surface reflectance. New AVIRIS-NG algorithms for retrieval of vegetation canopy water and for estimation of the fractions of photosynthetic, non-photosynthetic vegetation have been tested and evaluated on these measurements. An inflight calibration validation experiment was performed on the 11thof December 2015 in Hyderabad to assess the spectral and radiometric calibration of AVIRIS-NG in the flight environment. We present an overview of the campaign, calibration and validation results, and initial science analysis of a subset of these unique and diverse data sets.

Raman spectroscopy of saliva as a perspective method for periodontitis diagnostics Raman spectroscopy of saliva

Science.gov (United States)

Gonchukov, S.; Sukhinina, A.; Bakhmutov, D.; Minaeva, S.

2012-01-01

In view of its potential for biological tissues analyses at a molecular level, Raman spectroscopy in optical range has been the object of biomedical research for the last years. The main aim of this work is the development of Raman spectroscopy for organic content identifying and determination of biomarkers of saliva at a molecular level for periodontitis diagnostics. Four spectral regions were determined: 1155 and 1525 cm-1, 1033 and 1611 cm-1, which can be used as biomarkers of this widespread disease.

Water Orientation at Ceramide/Water Interfaces Studied by Heterodyne-Detected Vibrational Sum Frequency Generation Spectroscopy and Molecular Dynamics Simulation

KAUST Repository

Adhikari, Aniruddha

2016-10-10

Lipid/water interaction is essential for many biological processes. The water structure at the nonionic lipid interface remains little known, and there is no scope of a priori prediction of water orientation at nonionic interfaces, either. Here, we report our study combining advanced nonlinear spectroscopy and molecular dynamics simulation on the water orientation at the ceramide/water interface. We measured χ spectrum in the OH stretch region of ceramide/isotopically diluted water interface using heterodyne-detected vibrational sum-frequency generation spectroscopy and found that the interfacial water prefers an overall hydrogen-up orientation. Molecular dynamics simulation indicates that this preferred hydrogen-up orientation of water is determined by a delicate balance between hydrogen-up and hydrogen-down orientation induced by lipid-water and intralipid hydrogen bonds. This mechanism also suggests that water orientation at neutral lipid interfaces depends highly on the chemical structure of the lipid headgroup, in contrast to the charged lipid interfaces where the net water orientation is determined solely by the charge of the lipid headgroup.

Direct characterization of the energy level alignments and molecular components in an organic hetero-junction by integrated photoemission spectroscopy and reflection electron energy loss spectroscopy analysis.

Science.gov (United States)

Yun, Dong-Jin; Shin, Weon-Ho; Bulliard, Xavier; Park, Jong Hwan; Kim, Seyun; Chung, Jae Gwan; Kim, Yongsu; Heo, Sung; Kim, Seong Heon

2016-08-26

A novel, direct method for the characterization of the energy level alignments at bulk-heterojunction (BHJ)/electrode interfaces on the basis of electronic spectroscopy measurements is proposed. The home-made in situ photoemission system is used to perform x-ray/ultraviolet photoemission spectroscopy (XPS/UPS), reflection electron energy loss spectroscopy (REELS) and inverse photoemission spectroscopy of organic-semiconductors (OSCs) deposited onto a Au substrate. Through this analysis system, we are able to obtain the electronic structures of a boron subphthalocyanine chloride:fullerene (SubPC:C60) BHJ and those of the separate OSC/electrode structures (SubPC/Au and C60/Au). Morphology and chemical composition analyses confirm that the original SubPC and C60 electronic structures remain unchanged in the electrodes prepared. Using this technique, we ascertain that the position and area of the nearest peak to the Fermi energy (EF = 0 eV) in the UPS (REELS) spectra of SubPC:C60 BHJ provide information on the highest occupied molecular orbital level (optical band gap) and combination ratio of the materials, respectively. Thus, extracting the adjusted spectrum from the corresponding SubPC:C60 BHJ UPS (REELS) spectrum reveals its electronic structure, equivalent to that of the C60 materials. This novel analytical approach allows complete energy-level determination for each combination ratio by separating its electronic structure information from the BHJ spectrum.

Bulletin of Materials Science | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Bulletin of Materials Science; Volume 40; Issue 5. Optical spectroscopy of rare earth-doped oxyfluoro-tellurite glasses to probe local environment. GAJANAN V HONNAVAR K P RAMESH ... Keywords. Tellurite glasses; Raman spectroscopy; photoluminscence; Stark level splitting; UV visible spectroscopy.

Molecular thermodynamics for food science and engineering.

Science.gov (United States)

Nguyen, Phuong-Mai; Guiga, Wafa; Vitrac, Olivier

2016-10-01

We argue that thanks to molecular modeling approaches, many thermodynamic properties required in Food Science and Food Engineering will be calculable within a few hours from first principles in a near future. These new possibilities will enable to bridge via multiscale modeling composition, process and storage effects to reach global optimization, innovative concepts for food or its packaging. An outlook of techniques and a series of examples are given in this perspective. We emphasize solute chemical potentials in polymers, liquids and their mixtures as they cannot be understood and estimated without theory. The presented atomistic and coarse-grained methods offer a natural framework to their conceptualization in polynary systems, entangled or crosslinked homo- or heteropolymers. Copyright © 2016 Elsevier Ltd. All rights reserved.

3D Spectroscopy in Astronomy

Science.gov (United States)

Mediavilla, Evencio; Arribas, Santiago; Roth, Martin; Cepa-Nogué, Jordi; Sánchez, Francisco

2011-09-01

Preface; Acknowledgements; 1. Introductory review and technical approaches Martin M. Roth; 2. Observational procedures and data reduction James E. H. Turner; 3. 3D Spectroscopy instrumentation M. A. Bershady; 4. Analysis of 3D data Pierre Ferruit; 5. Science motivation for IFS and galactic studies F. Eisenhauer; 6. Extragalactic studies and future IFS science Luis Colina; 7. Tutorials: how to handle 3D spectroscopy data Sebastian F. Sánchez, Begona García-Lorenzo and Arlette Pécontal-Rousset.

Spectroscopy stepping stones

International Nuclear Information System (INIS)

Hammer, M.R.; Sturman, B.T.

2003-01-01

Determining the elemental composition of samples has long been a basic task of analytical science. Some very powerful and convenient approaches are based on the wavelength-specific absorption or emission of light by gas-phase atoms. Techniques briefly described as examples of analytical atomic spectrometry include atomic emission and absorption spectroscopy, inductively coupled plasma emission and mass spectroscopy and laser induced breakdown spectrometry

Raman spectroscopy in investigations of mechanism of binding of human serum albumin to molecular probe fluorescein

International Nuclear Information System (INIS)

Vlasova, I M; Saletsky, A M

2008-01-01

The mechanism of binding of molecular probe fluorescein to molecules of human serum albumin was studied by the Raman spectroscopy method. The position of binding Center on human serum albumin molecule for fluorescein is determined. The amino acid residues of albumin molecule, participating in binding of fluorescein at different pH values of solution, are established. The conformation rearrangements of globules of human serum albumin, taking place at binding of fluorescein at different pH values of solution, are registered

Laser-cooled atomic ions as probes of molecular ions

Energy Technology Data Exchange (ETDEWEB)

Brown, Kenneth R.; Viteri, C. Ricardo; Clark, Craig R.; Goeders, James E.; Khanyile, Ncamiso B.; Vittorini, Grahame D. [Schools of Chemistry and Biochemistry, Computational Science and Engineering and Physics, Georgia Institute of Technology, Atlanta, GA 30332 (United States)

2015-01-22

Trapped laser-cooled atomic ions are a new tool for understanding cold molecular ions. The atomic ions not only sympathetically cool the molecular ions to millikelvin temperatures, but the bright atomic ion fluorescence can also serve as a detector of both molecular reactions and molecular spectra. We are working towards the detection of single molecular ion spectra by sympathetic heating spectroscopy. Sympathetic heating spectroscopy uses the coupled motion of two trapped ions to measure the spectra of one ion by observing changes in the fluorescence of the other ion. Sympathetic heating spectroscopy is a generalization of quantum logic spectroscopy, but does not require ions in the motional ground state or coherent control of the ion internal states. We have recently demonstrated this technique using two isotopes of Ca{sup +} [Phys. Rev. A, 81, 043428 (2010)]. Limits of the method and potential applications for molecular spectroscopy are discussed.

Proceedings of the Third Symposium Optical Spectroscopy SOS-84

International Nuclear Information System (INIS)

Fassler, D.; Feller, K.H.; Wilhelmi, B.

1985-01-01

The main topics of the symposium were: 1) new developments and applications of laser spectroscopy including time resolved UV/VIS spectroscopy, time resolved fluorescence spectroscopy, and laser Raman spectroscopy, 2) dynamics and photokinetics of molecular systems, and 3) spectroscopy and photoprocesses in organized biological systems

Positron annihilation spectroscopy

International Nuclear Information System (INIS)

Sundar, C.S.; Viswanathan, B.

1996-01-01

An overview of positron annihilation spectroscopy, the experimental techniques and its application to studies on defects and electronic structure of materials is presented. The scope of this paper is to present the requisite introductory material, that will enable a better appreciation of the subsequent specialized articles on the applications of positron annihilation spectroscopy to investigate various problems in materials science. (author). 31 refs., 3 figs

Interaction of VUV-photons with molecules. Spectroscopy and dynamics of molecular superexcited states

International Nuclear Information System (INIS)

Hatano, Y.

2002-01-01

Complete text of publication follows. A survey is given of recent progress in experimental studies of the interaction of VUV-photons with molecules, i.e., those of photoabsorption, photoionization, and photodissociation of molecules in the excitation photon energy range of 10-50 eV, with a particular emphasis placed on current understanding of the spectroscopy and dynamics of formed molecular superexcited states. These studies are of great importance in understanding the interaction of ionizing radiation with matter. Molecules studied are ranged from simple diatomic and triatomic molecules to polyatomic molecules such as hydrocarbons. Most of the observed molecular superexcited states are assigned to high Rydber states which are vibrationally, doubly, or inner-core excited and converge to each of ion states. Non-Rydberg superexcited states are also observed. Dissociation into neutral fragments in comparison with ionization is of unexpectedly great importance in the observed decay of each of these state-assigned superexcited molecules. Dissociation dynamics as well as its products of superexcited states are remarkably different from those of lower excited states below about ionization thresholds. Some remarks are also presented of molecules in the condensed phase

Conformational study of sarcosine as probed by matrix-isolation FT-IR spectroscopy and molecular orbital calculations

OpenAIRE

Gómez-Zavaglia, Andrea; Fausto, R.

2003-01-01

Sarcosine (N-methylglycine) has been studied by matrix-isolation FT-IR spectroscopy and molecular orbital calculations undertaken at the DFT/B3LYP and MP2 levels of theory with the 6-311++G(d, p) and 6-31++G(d, p) basis set, respectively. Eleven different conformers were located in the potential energy surface (PES) of sarcosine, with the ASC conformer being the ground conformational state. This form is analogous to the glycine most stable conformer and is characterized by a NH...O= intramole...

Atomic and molecular spectroscopy basic concepts and applications

CERN Document Server

Kakkar, Rita

2015-01-01

Spectroscopy is the study of electromagnetic radiation and its interaction with solid, liquid, gas and plasma. It is one of the widely used analytical techniques to study the structure of atoms and molecules. The technique is also employed to obtain information about atoms and molecules as a result of their distinctive spectra. The fast-spreading field of spectroscopic applications has made a noteworthy influence on many disciplines, including energy research, chemical processing, environmental protection and medicine. This book aims to introduce students to the topic of spectroscopy. The author has avoided the mathematical aspects of the subject as far as possible; they appear in the text only when inevitable. Including topics such as time-dependent perturbation theory, laser action and applications of Group Theory in interpretation of spectra, the book offers a detailed coverage of the basic concepts and applications of spectroscopy.

Molecular recognition of malachite green by hemoglobin and their specific interactions: insights from in silico docking and molecular spectroscopy.

Science.gov (United States)

Peng, Wei; Ding, Fei; Peng, Yu-Kui; Sun, Ying

2014-01-01

Malachite green is an organic compound that can be widely used as a dyestuff for various materials; it has also emerged as a controversial agent in aquaculture. Since malachite green is proven to be carcinogenic and mutagenic, it may become a hazard to public health. For this reason, it is urgently required to analyze this controversial dye in more detail. In our current research, the interaction between malachite green and hemoglobin under physiological conditions was investigated by the methods of molecular modeling, fluorescence spectroscopy, circular dichroism (CD) as well as hydrophobic ANS displacement experiments. From the molecular docking, the central cavity of hemoglobin was assigned to possess high-affinity for malachite green, this result was corroborated by time-resolved fluorescence and hydrophobic ANS probe results. The recognition mechanism was found to be of static type, or rather the hemoglobin-malachite green complex formation occurred via noncovalent interactions such as π-π interactions, hydrogen bonds and hydrophobic interactions with an association constant of 10(4) M(-1). Moreover, the results also show that the spatial structure of the biopolymer was changed in the presence of malachite green with a decrease of the α-helix and increase of the β-sheet, turn and random coil suggesting protein damage, as derived from far-UV CD and three-dimensional fluorescence. Results of this work will help to further comprehend the molecular recognition of malachite green by the receptor protein and the possible toxicological profiles of other compounds, which are the metabolites and ramifications of malachite green.

Layman friendly spectroscopy

Science.gov (United States)

Sentic, Stipo; Sessions, Sharon

Affordable consumer grade spectroscopes (e.g. SCiO, Qualcomm Tricorder XPRIZE) are becoming more available to the general public. We introduce the concepts of spectroscopy to the public and K12 students and motivate them to delve deeper into spectroscopy in a dramatic participatory presentation and play. We use diffraction gratings, lasers, and light sources of different spectral properties to provide a direct experience of spectroscopy techniques. Finally, we invite the audience to build their own spectroscope--utilizing the APS SpectraSnapp cell phone application--and study light sources surrounding them in everyday life. We recontextualize the stigma that science is hard (e.g. ``Math, Science Popular Until Students Realize They're Hard,'' The Wall Street Journal) by presenting the material in such a way that it demonstrates the scientific method, and aiming to make failure an impersonal scientific tool--rather than a measure of one's ability, which is often a reason for shying away from science. We will present lessons we have learned in doing our outreach to audiences of different ages. This work is funded by the APS Outreach Grant ``Captain, we have matter matters!'' We thank New Mexico Tech Physics Department and Physics Club for help and technical equipment.

A guide to synchrotron radiation science

CERN Document Server

Sato, Shigeru; Munro, Ian; Lodha, G S

2015-01-01

Synchrotron Radiation (SR), as a light source is now in use around the world to provide brilliant radiation from the infrared into the soft and hard X-ray regions. It is an indispensible and essential tool to establish the physic-chemical characteristics of materials and surfaces from an atomic and molecular view point. It is being applied to topics which range from mineralogy to protein crystallography, embracing research in areas from the physical to the life sciences. This new guide is a concise yet comprehensive and easily readable introduction to an expanding area of science. It presents in a readily assimilable form the basic concepts of SR science from its generation principles, through source design and operation to the principles of instruments for SR exploitation followed by a survey of its actual applications in selected research fields, including spectroscopy, diffractometry, microanalysis and chemical processing.

HERSCHEL-SPIRE IMAGING SPECTROSCOPY OF MOLECULAR GAS IN M82

Energy Technology Data Exchange (ETDEWEB)

Kamenetzky, J.; Glenn, J.; Rangwala, N.; Maloney, P. [Center for Astrophysics and Space Astronomy, 389-UCB, University of Colorado, Boulder, CO 80303 (United States); Bradford, M. [NASA Jet Propulsion Laboratory, Pasadena, CA 91109 (United States); Wilson, C. D.; Schirm, M. R. P. [Department of Physics and Astronomy, McMaster University, Hamilton, Ontario L8S 4M1 (Canada); Bendo, G. J. [UK ALMA Regional Centre Node, Jordell Bank Center for Astrophysics, School of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL (United Kingdom); Baes, M. [Sterrenkundig Observatorium, Universiteit Gent, Krijgslaan 281 S9, 9000 Gent (Belgium); Boselli, A. [Laboratoire d' Astrophysique de Marseille, UMR6110 CNRS, 38 rue F. Joliot-Curie, 13388 Marseille (France); Cooray, A. [Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States); Isaak, K. G. [ESA Astrophysics Missions Division, ESTEC, P.O. Box 299, 2200 AG Noordwijk (Netherlands); Lebouteiller, V.; Madden, S.; Panuzzo, P.; Wu, R. [CEA, Laboratoire AIM, Irfu/SAp, Orme des Merisiers, 91191 Gif-sur-Yvette (France); Spinoglio, L. [Istituto di Fisica dello Spazio Interplanetario, INAF, Via del Fosso del Cavaliere 100, 00133 Roma (Italy)

2012-07-01

We present new Herschel-SPIRE imaging spectroscopy (194-671 {mu}m) of the bright starburst galaxy M82. Covering the CO ladder from J = 4 {yields} 3 to J = 13 {yields} 12, spectra were obtained at multiple positions for a fully sampled {approx}3 Multiplication-Sign 3 arcmin map, including a longer exposure at the central position. We present measurements of {sup 12}CO, {sup 13}CO, [C I], [N II], HCN, and HCO{sup +} in emission, along with OH{sup +}, H{sub 2}O{sup +}, and HF in absorption and H{sub 2}O in both emission and absorption, with discussion. We use a radiative transfer code and Bayesian likelihood analysis to model the temperature, density, column density, and filling factor of multiple components of molecular gas traced by {sup 12}CO and {sup 13}CO, adding further evidence to the high-J lines tracing a much warmer ({approx}500 K), less massive component than the low-J lines. The addition of {sup 13}CO (and [C I]) is new and indicates that [C I] may be tracing different gas than {sup 12}CO. No temperature/density gradients can be inferred from the map, indicating that the single-pointing spectrum is descriptive of the bulk properties of the galaxy. At such a high temperature, cooling is dominated by molecular hydrogen. Photon-dominated region (PDR) models require higher densities than those indicated by our Bayesian likelihood analysis in order to explain the high-J CO line ratios, though cosmic-ray-enhanced PDR models can do a better job reproducing the emission at lower densities. Shocks and turbulent heating are likely required to explain the bright high-J emission.

Exciton–vibrational coupling in the dynamics and spectroscopy of Frenkel excitons in molecular aggregates

International Nuclear Information System (INIS)

Schröter, M.; Ivanov, S.D.; Schulze, J.; Polyutov, S.P.; Yan, Y.; Pullerits, T.; Kühn, O.

2015-01-01

The influence of exciton–vibrational coupling on the optical and transport properties of molecular aggregates is an old problem that gained renewed interest in recent years. On the experimental side, various nonlinear spectroscopic techniques gave insight into the dynamics of systems as complex as photosynthetic antennae. Striking evidence was gathered that in these protein–pigment complexes quantum coherence is operative even at room temperature conditions. Investigations were triggered to understand the role of vibrational degrees of freedom, beyond that of a heat bath characterized by thermal fluctuations. This development was paralleled by theory, where efficient methods emerged, which could provide the proper frame to perform non-Markovian and non-perturbative simulations of exciton–vibrational dynamics and spectroscopy. This review summarizes the state of affairs of the theory of exciton–vibrational interaction in molecular aggregates and photosynthetic antenna complexes. The focus is put on the discussion of basic effects of exciton–vibrational interaction from the stationary and dynamics points of view. Here, the molecular dimer plays a prominent role as it permits a systematic investigation of absorption and emission spectra by numerical diagonalization of the exciton–vibrational Hamiltonian in a truncated Hilbert space. An extension to larger aggregates, having many coupled nuclear degrees of freedom, becomes possible with the Multi-Layer Multi-Configuration Time-Dependent Hartree (ML-MCTDH) method for wave packet propagation. In fact it will be shown that this method allows one to approach the limit of almost continuous spectral densities, which is usually the realm of density matrix theory. Real system–bath situations are introduced for two models, which differ in the way strongly coupled nuclear coordinates are treated, as a part of the relevant system or the bath. A rather detailed exposition of the Hierarchy Equations Of Motion (HEOM

Art Advancing Science: Filmmaking Leads to Molecular Insights at the Nanoscale.

Science.gov (United States)

Reilly, Charles; Ingber, Donald E

2017-12-26

Many have recognized the potential value of facilitating activities that span the art-science interface for the benefit of society; however, there are few examples that demonstrate how pursuit of an artistic agenda can lead to scientific insights. Here, we describe how we set out to produce an entertaining short film depicting the fertilization of the egg by sperm as a parody of a preview for another Star Wars movie to excite the public about science, but ended up developing a simulation tool for multiscale modeling. To produce an aesthetic that communicates mechanical continuity across spatial scales, we developed custom strategies that integrate physics-based animation software from the entertainment industry with molecular dynamics simulation tools, using experimental data from research publications. Using this approach, we were able to depict biological physicality across multiple spatial scales, from how sperm tails move to collective molecular behavior within the axoneme to how the molecular motor, dynein, produces force at the nanometer scale. The dynein simulations, which were validated by replicating results of past simulations and cryo-electron microscopic studies, also predicted a potential mechanism for how ATP hydrolysis drives dynein motion along the microtubule as well as how dynein changes its conformation when it goes through the power stroke. Thus, pursuit of an artistic work led to insights into biology at the nanoscale as well as the development of a highly generalizable modeling and simulation technology that has utility for nanoscience and any other area of scientific investigation that involves analysis of complex multiscale systems.

Ion-atom interactions probed by photofragment spectroscopy

International Nuclear Information System (INIS)

Helm, H.

1984-01-01

Photofragment spectroscopy studies energetic and dynamical properties of molecular states interacting with dissociation continuum. So far, data for eighteen diatomic molecular ions have been gathered by this technique. This paper is a review of these investigations, introduced by a discussion of the experimental methods used. The wealth of information accessible by ion photofragment spectroscopy challenges the experimentalist in the application of innovative techniques and the theoretician for less approximate accounts of the Hamiltonian. (Auth.)

Study of simple super-critical fluids (CO2, C2D6) through neutron scattering, Raman spectroscopy and molecular dynamic simulations

International Nuclear Information System (INIS)

Longelin, St.

2004-04-01

Super-critical fluids are largely used in industrial sectors. However the knowledge of the physical phenomena in which they are involved stays insufficient because of their particular properties. A new model of adjusting molecular structures is proposed, this model has been validated through neutron scattering experiments with high momentum transfer on C 2 D 6 . The experimental representation of the critical universal function for C 2 D 6 and CO 2 has been obtained through the neutron echo spin and by relying on structure measurements made through neutron elastic scattering at small angles. Raman spectroscopy and molecular dynamics simulation have been used to feature structure and dynamics. Scattering as well as microscopic molecular density fluctuations have been analysed

Investigation of the spectroscopy and relaxation dynamics of benzaldehyde using molecular orbital calculations and laser ionization time-of-flight mass spectroscopy

Science.gov (United States)

da Silva, Maria Cristina Rodrigues

1998-11-01

Molecular orbital methods and laser ionization mass spectrometry measurements are used to investigate the spectroscopy and relaxation dynamics of benzaldehyde following excitation to its S2(/pi/pi/sp/*) state. Energies, equilibrium geometries and vibrational frequencies of ground and low-lying excited states of benzaldehyde neutral and cation determined by ab initio calculations provide a theoretical description of the electronic spectroscopy of benzaldehyde and of the changes occurring on excitation and ionization. The S2(/pi/pi/sp/*)[/gets]S0 excitation spectrum of jet-cooled benzaldehyde acquired using two-color laser ionization mass spectrometry techniques is interpreted with the aid of these calculations. The spectrum is dominated by the origin band and by transitions involving some of the ring modes consistent with the results of the molecular orbital calculations that indicate that the major geometric changes on excitation to S2 are located in the aromatic ring. Ten fundamental vibrations of the S2(/pi/pi/sp/*) state are assigned. The dissociation dynamics of benzaldehyde into benzene and carbon monoxide following excitation to its S2(/pi/pi/sp/*) state are investigated under jet- cooled conditions by two-color laser ionization mass spectrometry using a pump-probe technique. This experimental arrangement allows monitoring the benzaldehyde reactant and the benzene product ion signals as a function of the time delay between the excitation and ionization steps. A kinetic model is proposed to explain the observed biexponential decay of the benzaldehyde signal and the single exponential growth of the benzene product signal in terms of a sequential decay of two excited states of benzaldehyde, one of which leads to formation of benzene molecules in its lowest triplet state. Reactant disappearance and product appearance rates are determined for a number of vibronic transitions of the S2 state. They are found to increase with excitation energy without any indication

Role of Raman spectroscopy and surface enhanced Raman spectroscopy in colorectal cancer

Science.gov (United States)

Jenkins, Cerys A; Lewis, Paul D; Dunstan, Peter R; Harris, Dean A

2016-01-01

Colorectal cancer (CRC) is the fourth most common cancer in the United Kingdom and is the second largest cause of cancer related death in the United Kingdom after lung cancer. Currently in the United Kingdom there is not a diagnostic test that has sufficient differentiation between patients with cancer and those without cancer so the current referral system relies on symptomatic presentation in a primary care setting. Raman spectroscopy and surface enhanced Raman spectroscopy (SERS) are forms of vibrational spectroscopy that offer a non-destructive method to gain molecular information about biological samples. The techniques offer a wide range of applications from in vivo or in vitro diagnostics using endoscopic probes, to the use of micro-spectrometers for analysis of biofluids. The techniques have the potential to detect molecular changes prior to any morphological changes occurring in the tissue and therefore could offer many possibilities to aid the detection of CRC. The purpose of this review is to look at the current state of diagnostic technology in the United Kingdom. The development of Raman spectroscopy and SERS in clinical applications relation for CRC will then be discussed. Finally, future areas of research of Raman/SERS as a clinical tool for the diagnosis of CRC are also discussed. PMID:27190582

Attosecond transient absorption spectroscopy of molecular hydrogen

International Nuclear Information System (INIS)

Martín, Fernando; González-Castrillo, Alberto; Palacios, Alicia; Argenti, Luca; Cheng, Yan; Chini, Michael; Wang, Xiaowei; Chang, Zenghu

2015-01-01

We extend attosecond transient absorption spectroscopy (ATAS) to the study of hydrogen molecules, demonstrating the potential of the technique to resolve – simultaneously and with state resolution – both the electronic and nuclear dynamics. (paper)

An ab initio molecular

Indian Academy of Sciences (India)

mechanisms of two molecular crystals: An ab initio molecular dynamics ... for Computation in Molecular and Materials Science and Department of Chemistry, School of ..... NSAF Foundation of National Natural Science Foun- ... Matter 14 2717.

Educational Challenges of Molecular Life Science: Characteristics and Implications for Education and Research

Science.gov (United States)

Tibell, Lena A. E.; Rundgren, Carl-Johan

2010-01-01

Molecular life science is one of the fastest-growing fields of scientific and technical innovation, and biotechnology has profound effects on many aspects of daily life--often with deep, ethical dimensions. At the same time, the content is inherently complex, highly abstract, and deeply rooted in diverse disciplines ranging from "pure…

IR Spectroscopy. An introduction

International Nuclear Information System (INIS)

Guenzler, H.; Gremlich, H.U.

2002-01-01

The following topics are dealt with: absorption and molecular design, spectrometers, sample preparation, qualitative spectral interpretation and assertions, near-infrared and far-infrared spectroscopy, reference spectra and expert systems

Aureochrome 1 illuminated: structural changes of a transcription factor probed by molecular spectroscopy.

Directory of Open Access Journals (Sweden)

Silke Kerruth

Full Text Available Aureochrome 1 from Vaucheria frigida is a recently identified blue-light receptor that acts as a transcription factor. The protein comprises a photosensitive light-, oxygen- and voltage-sensitive (LOV domain and a basic zipper (bZIP domain that binds DNA rendering aureochrome 1 a prospective optogenetic tool. Here, we studied the photoreaction of full-length aureochrome 1 by molecular spectroscopy. The kinetics of the decay of the red-shifted triplet state and the blue-shifted signaling state were determined by time-resolved UV/Vis spectroscopy. It is shown that the presence of the bZIP domain further prolongs the lifetime of the LOV390 signaling state in comparison to the isolated LOV domain whereas bound DNA does not influence the photocycle kinetics. The light-dark Fourier transform infrared (FTIR difference spectrum shows the characteristic features of the flavin mononucleotide chromophore except that the S-H stretching vibration of cysteine 254, which is involved in the formation of the thio-adduct state, is significantly shifted to lower frequencies compared to other LOV domains. The presence of the target DNA influences the light-induced FTIR difference spectrum of aureochrome 1. Vibrational bands that can be assigned to arginine and lysine side chains as well to the phosphate backbone, indicate crucial changes in interactions between transcription factor and DNA.

Coherent atomic and molecular spectroscopy in the far infrared

International Nuclear Information System (INIS)

Inguscio, M.

1988-01-01

Recent advances in far infrared spectroscopy of atoms (fine structure transitions) and molecules (rotational transitions) are reviewed. Results obtained by means of Laser Magnetic Resonance, using fixed frequency lasers, and Tunable Far Infrared spectrometers are illustrated. The importance of far infrared spectroscopy for several fields, including astrophysics, atmospheric physics, atomic structure and metology, is discussed. (orig.)

Spectroscopy, Understanding the Atom Series.

Science.gov (United States)

Hellman, Hal

This booklet is one of the "Understanding the Atom" Series. The science of spectroscopy is presented by a number of topics dealing with (1) the uses of spectroscopy, (2) its origin and background, (3) the basic optical systems of spectroscopes, spectrometers, and spectrophotometers, (4) the characteristics of wave motion, (5) the…

Charge carrier mobility in poly[methyl(phenyl)silylene] studied by time-resolved terahertz spectroscopy and molecular modeling

Czech Academy of Sciences Publication Activity Database

Němec, Hynek; Kratochvílová, Irena; Kužel, Petr; Šebera, Jakub; Kochalska, Anna; Nožár, Juraj; Nešpůrek, Stanislav

2011-01-01

Roč. 13, č. 7 (2011), s. 2850-2856 ISSN 1463-9076 R&D Projects: GA ČR(CZ) GP202/09/P099; GA ČR GA203/08/1594; GA AV ČR KAN401770651; GA MŠk LC512; GA ČR(CZ) GAP304/10/1951 Institutional research plan: CEZ:AV0Z10100520; CEZ:AV0Z40500505 Keywords : molecular electronics * THz spectroscopy * charge carrier mobility Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.573, year: 2011

Molecular Level Structure and Dynamics of Electrolytes Using 17O Nuclear Magnetic Resonance Spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Murugesan, Vijayakumar; Han, Kee Sung; Hu, Jianzhi; Mueller, Karl T.

2017-03-19

Electrolytes help harness the energy from electrochemical processes by serving as solvents and transport media for redox-active ions. Molecular-level interactions between ionic solutes and solvent molecules – commonly referred to as solvation phenomena – give rise to many functional properties of electrolytes such as ionic conductivity, viscosity, and stability. It is critical to understand the evolution of solvation phenomena as a function of competing counterions and solvent mixtures to predict and design the optimal electrolyte for a target application. Probing oxygen environments is of great interest as oxygens are located at strategic molecular sites in battery solvents and are directly involved in inter- and intramolecular solvation interactions. NMR signals from 17O nuclei in battery electrolytes offer nondestructive bulk measurements of isotropic shielding, electric field gradient tensors, and transverse and longitudinal relaxation rates, which are excellent means for probing structure, bonding, and dynamics of both solute and solvent molecules. This article describes the use of 17O NMR spectroscopy in probing the solvation structures of various electrolyte systems ranging from transition metal ions in aqueous solution to lithium cations in organic solvent mixtures.

Infrared and Raman Spectroscopy of Liquid Water through "First-Principles" Many-Body Molecular Dynamics.

Science.gov (United States)

Medders, Gregory R; Paesani, Francesco

2015-03-10

Vibrational spectroscopy is a powerful technique to probe the structure and dynamics of water. However, deriving an unambiguous molecular-level interpretation of the experimental spectral features remains a challenge due to the complexity of the underlying hydrogen-bonding network. In this contribution, we present an integrated theoretical and computational framework (named many-body molecular dynamics or MB-MD) that, by systematically removing uncertainties associated with existing approaches, enables a rigorous modeling of vibrational spectra of water from quantum dynamical simulations. Specifically, we extend approaches used to model the many-body expansion of interaction energies to develop many-body representations of the dipole moment and polarizability of water. The combination of these "first-principles" representations with centroid molecular dynamics simulations enables the simulation of infrared and Raman spectra of liquid water under ambient conditions that, without relying on any ad hoc parameters, are in good agreement with the corresponding experimental results. Importantly, since the many-body energy, dipole, and polarizability surfaces employed in the simulations are derived independently from accurate fits to correlated electronic structure data, MB-MD allows for a systematic analysis of the calculated spectra in terms of both electronic and dynamical contributions. The present analysis suggests that, while MB-MD correctly reproduces both the shifts and the shapes of the main spectroscopic features, an improved description of quantum dynamical effects possibly combined with a dissociable water potential may be necessary for a quantitative representation of the OH stretch band.

Molecular spectroscopy in biodiagnostics (from Hippocrates to Herschel and beyond)

Science.gov (United States)

Mantsch, Henry; Jackson, Michael

1995-03-01

After two decades of intense research on the spectroscopic properties of biological molecules in isolated systems, infrared spectroscopy is now being applied to the study of human tissues. Extending this approach, it is possible to use the sensitivity of infrared spectroscopy to probe the biochemical events underlying transformation from normal to a diseased state within tissues, and so develop novel diagnostic methods. We highlight some of the areas of research within our group aimed at developing clinically useful methodologies based upon infrared spectroscopy.

Characterization of the Interaction between Gallic Acid and Lysozyme by Molecular Dynamics Simulation and Optical Spectroscopy

Directory of Open Access Journals (Sweden)

Minzhong Zhan

2015-07-01

Full Text Available The binding interaction between gallic acid (GA and lysozyme (LYS was investigated and compared by molecular dynamics (MD simulation and spectral techniques. The results from spectroscopy indicate that GA binds to LYS to generate a static complex. The binding constants and thermodynamic parameters were calculated. MD simulation revealed that the main driving forces for GA binding to LYS are hydrogen bonding and hydrophobic interactions. The root-mean-square deviation verified that GA and LYS bind to form a stable complex, while the root-mean-square fluctuation results showed that the stability of the GA-LYS complex at 298 K was higher than that at 310 K. The calculated free binding energies from the molecular mechanics/Poisson-Boltzmann surface area method showed that van der Waals forces and electrostatic interactions are the predominant intermolecular forces. The MD simulation was consistent with the spectral experiments. This study provides a reference for future study of the pharmacological mechanism of GA.

Sulfur amino acids and alanine on pyrite (100) by X-ray photoemission spectroscopy: Surface or molecular role?

Energy Technology Data Exchange (ETDEWEB)

Sanchez-Arenillas, M.; Galvez-Martinez, S.; Mateo-Marti, E., E-mail: mateome@cab.inta-csic.es

2017-08-31

Highlights: • Surface annealing pretreatment on pyrite surfaces can select molecular adsorption. • Enriched monosulfide species on pyrite (100) surface favors NH{sub 2} adsorption form. • Enriching disulfide species on pyrite (100) surface promotes NH{sub 3}{sup +} adsorption form. • Unique structure of each aminoacid provides a particular fingerprint in the process. • Spectroscopy evidence, pretreatment surface processes drives molecular adsorption. - Abstract: This paper describes the first successful adsorption of the cysteine, cystine, methionine and alanine amino acids on the pyrite (100) surface under ultra-high vacuum conditions with crucial chemical adsorption parameters driving the process. We have demonstrated by X-ray photoemission spectroscopy (XPS) that the surface pretreatment annealing process on pyrite surfaces is a critical parameter driving surface reactivity. The presence of enriched monosulfide species on the pyrite (100) surface favours the amino acid NH{sub 2} chemical form, whereas a longer annealing surface pretreatment of over 3 h repairs the sulfur vacancies in the pyrite, enriching disulfide species on the pyrite surface, which promotes NH{sub 3}{sup +} adsorption due to the sulfur vacancies in the pyrite being replaced by sulfur atom dimers (S{sub 2}{sup 2−}) on the surface. Furthermore, even if the surface chemistry (monosulfide or disulfide species enrichment) is the main factor promoting a partial conversion from NH{sub 2} to NH{sub 3}{sup +} species, the unique chemical structure of each amino acid provides a particular fingerprint in the process.

Reactive molecular beam epitaxial growth and in situ photoemission spectroscopy study of iridate superlattices

Directory of Open Access Journals (Sweden)

C. C. Fan

2017-08-01

Full Text Available High-quality (001-oriented perovskite [(SrIrO3m/(SrTiO3] superlattices (m=1/2, 1, 2, 3 and ∞ films have been grown on SrTiO3(001 epitaxially using reactive molecular beam epitaxy. Compared to previously reported superlattices synthesized by pulsed laser deposition, our superlattices exhibit superior crystalline, interface and surface structure, which have been confirmed by high-resolution X-ray diffraction, scanning transmission electron microscopy and atomic force microscopy, respectively. The transport measurements confirm a novel insulator-metal transition with the change of dimensionality in these superlattices, and our first systematic in situ photoemission spectroscopy study indicates that the increasing strength of effective correlations induced by reducing dimensionality would be the dominating origin of this transition.

New all-optical method for measuring molecular permanent dipole moment difference using two-photon absorption spectroscopy

International Nuclear Information System (INIS)

Rebane, A.; Drobizhev, M.; Makarov, N.S.; Beuerman, E.; Tillo, S.; Hughes, T.

2010-01-01

Stark effect, in combination with spectral hole burning and single-molecule spectroscopy, has been a fruitful technique to study permanent electric dipole moment of molecules in condensed phase. However, because measuring Stark shifts relies on external fields and narrow line- or hole-widths, the applicability of this method at ambient conditions required by most biological systems has remained limited. Here we demonstrate a new all-optical method for measuring the molecular dipole moment difference between ground and excited states using two-photon absorption (2PA) spectroscopy. We show that the value and orientation of the static dipole moment difference can be determined from the corresponding absolute 2PA cross-section. We use this new method to determine for the first time the strength of local electric field E loc =0.1-1.0x10 8 V/cm inside beta-barrel of Fruit series of red fluorescent proteins. Because our method does not rely on external field and is applicable in liquid solutions, it is well suited for the study of biological systems.

Supra-molecular networks for CO2 capture

Science.gov (United States)

Sadowski, Jerzy; Kestell, John

Utilizing capabilities of low-energy electron microscopy (LEEM) for non-destructive interrogation of the real-time molecular self-assembly, we have investigated supramolecular systems based on carboxylic acid-metal complexes, such as trimesic and mellitic acid, doped with transition metals. Such 2D networks can act as host systems for transition-metal phthalocyanines (MPc; M = Fe, Ti, Sc). The electrostatic interactions of CO2 molecules with transition metal ions can be tuned by controlling the type of TM ion and the size of the pore in the host network. We further applied infrared reflection-absorption spectroscopy (IRRAS) to determine of the molecular orientation of the functional groups and the whole molecule in the 2D monolayers of carboxylic acid. The kinetics and mechanism of the CO2 adsorption/desorption on the 2D molecular network, with and without the TM ion doping, have been also investigated. This research used resources of the Center for Functional Nanomaterials, which is the U.S. DOE Office of Science User Facility, at Brookhaven National Laboratory under Contract No. DE-SC0012704.

Photoelectron spectroscopy of supersonic molecular beams

International Nuclear Information System (INIS)

Pollard, J.E.; Trevor, D.J.; Lee, Y.T.; Shirley, D.A.

1981-01-01

A high-resolution photoelectron spectrometer which uses molecular beam sampling is described. Photons from a rare-gas resonance lamp or UV laser are crossed with the beam from a differentially pumped supersonic nozzle source. The resulting photoelectrons are collected by an electrostatic analyzer of a unique design consisting of a 90 0 spherical sector preanalyzer, a system of lenses, and a 180 0 hemispherical deflector. A multichannel detection system based on dual microchannel plates with a resistive anode position encoder provides an increase in counting efficiency by a factor of 12 over the equivalent single channel detector. The apparatus has demonstrated an instrumental resolution of better than 10 meV FWHM, limited largely by the photon source linewidth. A quadrupole mass spectrometer is used to characterize the composition of the molecular beam. Extensive differential pumping is provided to protect the critical surfaces of the analyzer and mass spectrometer from contamination. Because of the near elimination of Doppler and rotational broadenings, the practical resolution is the highest yet obtained in molecular PES

Ultrafast Laser-Based Spectroscopy and Sensing: Applications in LIBS, CARS, and THz Spectroscopy

Science.gov (United States)

Leahy-Hoppa, Megan R.; Miragliotta, Joseph; Osiander, Robert; Burnett, Jennifer; Dikmelik, Yamac; McEnnis, Caroline; Spicer, James B.

2010-01-01

Ultrafast pulsed lasers find application in a range of spectroscopy and sensing techniques including laser induced breakdown spectroscopy (LIBS), coherent Raman spectroscopy, and terahertz (THz) spectroscopy. Whether based on absorption or emission processes, the characteristics of these techniques are heavily influenced by the use of ultrafast pulses in the signal generation process. Depending on the energy of the pulses used, the essential laser interaction process can primarily involve lattice vibrations, molecular rotations, or a combination of excited states produced by laser heating. While some of these techniques are currently confined to sensing at close ranges, others can be implemented for remote spectroscopic sensing owing principally to the laser pulse duration. We present a review of ultrafast laser-based spectroscopy techniques and discuss the use of these techniques to current and potential chemical and environmental sensing applications. PMID:22399883

Ultrafast Laser-Based Spectroscopy and Sensing: Applications in LIBS, CARS, and THz Spectroscopy

Directory of Open Access Journals (Sweden)

Megan R. Leahy-Hoppa

2010-04-01

Full Text Available Ultrafast pulsed lasers find application in a range of spectroscopy and sensing techniques including laser induced breakdown spectroscopy (LIBS, coherent Raman spectroscopy, and terahertz (THz spectroscopy. Whether based on absorption or emission processes, the characteristics of these techniques are heavily influenced by the use of ultrafast pulses in the signal generation process. Depending on the energy of the pulses used, the essential laser interaction process can primarily involve lattice vibrations, molecular rotations, or a combination of excited states produced by laser heating. While some of these techniques are currently confined to sensing at close ranges, others can be implemented for remote spectroscopic sensing owing principally to the laser pulse duration. We present a review of ultrafast laser-based spectroscopy techniques and discuss the use of these techniques to current and potential chemical and environmental sensing applications.

Belowground Carbon Cycling Processes at the Molecular Scale: An EMSL Science Theme Advisory Panel Workshop

Energy Technology Data Exchange (ETDEWEB)

Hess, Nancy J.; Brown, Gordon E.; Plata, Charity

2014-02-21

As part of the Belowground Carbon Cycling Processes at the Molecular Scale workshop, an EMSL Science Theme Advisory Panel meeting held in February 2013, attendees discussed critical biogeochemical processes that regulate carbon cycling in soil. The meeting attendees determined that as a national scientific user facility, EMSL can provide the tools and expertise needed to elucidate the molecular foundation that underlies mechanistic descriptions of biogeochemical processes that control carbon allocation and fluxes at the terrestrial/atmospheric interface in landscape and regional climate models. Consequently, the workshop's goal was to identify the science gaps that hinder either development of mechanistic description of critical processes or their accurate representation in climate models. In part, this report offers recommendations for future EMSL activities in this research area. The workshop was co-chaired by Dr. Nancy Hess (EMSL) and Dr. Gordon Brown (Stanford University).

Molecular-beam spectroscopy of interhalogen molecules

International Nuclear Information System (INIS)

Sherrow, S.A.

1983-08-01

A molecular-beam electric-resonance spectrometer employing a supersonic nozzle source has been used to obtain hyperfine spectra of 79 Br 35 Cl. Analyses of these spectra and of microwave spectra published by other authors have yielded new values for the electric dipole moment and for the nuclear quadrupole coupling constants in this molecule. The new constants are significantly different from the currently accepted values. Van der Waals clusters containing chlorine monofluoride have been studied under various expansion conditions by the molecular-beam electric-deflection method. The structural possibilities indicated by the results are discussed, and cluster geometries are proposed

Experimental atomic and molecular physics research

International Nuclear Information System (INIS)

Anon.

1980-01-01

The Atomic Physics research in the Physics Division consists of five ongoing experimental programs: dissociation and other interactions of energetic molecular ions in solid and gaseous targets; beam-foil research and collision dynamics of heavy ions; photoionization-photoelectron research; spectroscopy of free atoms and molecules, high precision laser-rf double-resonance spectroscopy with atomic and molecular beams; and Moessbauer effect research

Atomic and molecular sciences. Progress report No. 8, April 1, 1981-March 31, 1982

International Nuclear Information System (INIS)

Walters, G.K.; Lane, N.F.

1981-01-01

The atomic and molecular physics program at Rice University addresses fundamental problems in structure, radiation-induced gas- and condensed-phase reaction kinetics and dynamics, and the mutual interactions of radiation, atoms, molecules, electrons and ions, particularly in highly unusual or exotic environments. The program emphasizes fundamental studies relating to new sources of energy, with close interaction between experimental and theoretical aspects of the research. Progress in the experimental program is reported in two principal areas, A) time resolved spectroscopy, and B) reactions in a flowing helium afterglow

C-Ni-Pd and CNT-Ni-Pd film's molecular and crystalline structure investigations by FTIR spectroscopy and XRD diffraction

Science.gov (United States)

Stepińska, Izabela; Czerwosz, ElŻbieta; Diduszko, Ryszard; Kozłowski, Mirosław; Wronka, Halina

2017-08-01

In this work molecular and crystalline structure of new type of nanocomposite films were investigated. These films compose of CNT decorated with palladium nanograins. They were prepared on a base of C-Ni films modified in CVD process. C-Ni nanocomposite films were obtained by PVD process and their modification by CVD leads to a growth of CNT film. CNTs-Ni or C-Ni films were treated with additional PVD process with palladium. Nickel and palladium acetate and fulleren C60 are precursors of films in PVD process. FTIR spectroscopy was used to studied the molecular structure of film in every stage of preparation . The crystalline structure of these films was studied by X-ray diffraction. SEM (scanning electron microscopy) was applied to investigate film's surface topography.

EDITORIAL: Nano Meets Spectroscopy Nano Meets Spectroscopy

Science.gov (United States)

Birch, David J. S.

2012-08-01

The multidisciplinary two-day Nano Meets Spectroscopy (NMS) event was held at the National Physical Laboratory (NPL), Teddington, UK, in September 2011. The event was planned from the outset to be at the interface of several areas—in particular, spectroscopy and nanoscience, and to bring together topics and people with different approaches to achieving common goals in biomolecular science. Hence the meeting cut across traditional boundaries and brought together researchers using diverse techniques, particularly fluorescence and Raman spectroscopy. Despite engaging common problems, these techniques are frequently seen as mutually exclusive with the two communities rarely interacting at conferences. The meeting was widely seen to have lived up to its billing in good measure. It attracted the maximum capacity of ~120 participants, including 22 distinguished speakers (9 from outside the UK), over 50 posters and a vibrant corporate exhibition comprising 10 leading instrument companies and IOP Publishing. The organizers were Professor David Birch (Chair), Dr Karen Faulds and Professor Duncan Graham of the University of Strathclyde, Professor Cait MacPhee of the University of Edinburgh and Dr Alex Knight of NPL. The event was sponsored by the European Science Foundation, the Institute of Physics, the Royal Society of Chemistry, NPL and the Scottish Universities Physics Alliance. The full programme and abstracts are available at http://sensor.phys.strath.ac.uk/nms/program.php. The programme was quite ambitious in terms of the breadth and depth of scope. The interdisciplinary and synergistic concept of 'X meets Y' played well, cross-fertilization between different fields often being a source of inspiration and progress. Fluorescence and Raman spectroscopy provided the core, but the meeting had little repetition and also attracted contributions on more specialist techniques such as CARS, super-resolution, single molecule and chiral methods. In terms of application the

Optical second-harmonic and reflectance-anisotropy spectroscopy of molecular adsorption at Si(001) step-edges

Energy Technology Data Exchange (ETDEWEB)

Ehlert, Robert; Kwon, Jinhee; Downer, Michael C. [University of Texas at Austin, Department of Physics, Austin, TX 78712-1081 (United States)

2008-07-01

Reflectance-anisotropy spectroscopy (RAS) and spectroscopic second harmonic generation (SHG) are used to probe a single-domain reconstructed stepped Si(001) surface offcut 6 toward[110] before and after dissociative adsorption of H{sub 2} at the D{sub B} step edges. Preliminary analysis with a simplified bond hyperpolarizability model supports the mutual consistency of RA and SHG spectra and suggests that hydrogen termination redistributes oscillator strength from the chemically active step dangling bond into the step back bonds. The data provide a benchmark for first-principles calculations of the optical response of stepped Si surfaces to step edge molecular adsorption. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Bulletin of Materials Science | Indian Academy of Sciences

Indian Academy of Sciences (India)

Hirshfeld surface analysis for visually analysing intermolecular interactions in crystal structures employing molecular surfacecontours and 2D fingerprint plots has been used to scrutinize molecular shapes. The vibration properties of this structure were studied by IR spectroscopy and Raman scattering. Vibration spectra ...

Rosalind Franklin and the DNA molecular structure: A case of history of science to learn about the nature of science

Directory of Open Access Journals (Sweden)

José Antonio Acevedo-Díaz

2016-08-01

Full Text Available The Rosalind Franklin’s case regarding the elucidation of the molecular structure of DNA is presented as an interesting story of the history of science to address a set of questions related to the nature of science (NOS from an explicit and reflective approach. The teaching proposal is aimed to the pre-service teachers training in NOS issues and its didactics. Attention is given to both epistemic and non-epistemic aspects in the narration and the NOS questions asked for reflecting about them. Also, some methodological recommendations for implementing the didactic proposal in science classroom are offered. This involves the follows: (i in small groups, the students read the controversy and respond to some questions on NOS; (ii they present their responses to the whole-class; and (iii they revise their initial responses in light of the whole-class discussion.

Single-Molecule Spectroscopy

Indian Academy of Sciences (India)

Home; Journals; Resonance – Journal of Science Education; Volume 20; Issue 2. Single-Molecule Spectroscopy: Every Molecule is Different! Kankan Bhattacharyya. General Article Volume 20 Issue 2 February 2015 pp 151-164. Fulltext. Click here to view fulltext PDF. Permanent link:

Surface-Enhanced Raman Scattering in Molecular Junctions.

Science.gov (United States)

Iwane, Madoka; Fujii, Shintaro; Kiguchi, Manabu

2017-08-18

Surface-enhanced Raman scattering (SERS) is a surface-sensitive vibrational spectroscopy that allows Raman spectroscopy on a single molecular scale. Here, we present a review of SERS from molecular junctions, in which a single molecule or molecules are made to have contact from the top to the bottom of metal surfaces. The molecular junctions are nice platforms for SERS as well as transport measurement. Electronic characterization based on the transport measurements of molecular junctions has been extensively studied for the development of miniaturized electronic devices. Simultaneous SERS and transport measurement of the molecular junctions allow both structural (geometrical) and electronic information on the single molecule scale. The improvement of SERS measurement on molecular junctions open the door toward new nanoscience and nanotechnology in molecular electronics.

Trimethylamine-N-oxide: its hydration structure, surface activity, and biological function, viewed by vibrational spectroscopy and molecular dynamics simulations.

Science.gov (United States)

Ohto, Tatsuhiko; Hunger, Johannes; Backus, Ellen H G; Mizukami, Wataru; Bonn, Mischa; Nagata, Yuki

2017-03-08

The osmolyte molecule trimethylamine-N-oxide (TMAO) stabilizes the structure of proteins. As functional proteins are generally found in aqueous solutions, an important aspect of this stabilization is the interaction of TMAO with water. Here, we review, using vibrational spectroscopy and molecular dynamics simulations, recent studies on the structure and dynamics of TMAO with its surrounding water molecules. This article ends with an outlook on the open questions on TMAO-protein and TMAO-urea interactions in aqueous environments.

Ultrafast infrared vibrational spectroscopy

CERN Document Server

Fayer, Michael D

2013-01-01

The past ten years or so have seen the introduction of multidimensional methods into infrared and optical spectroscopy. The technology of multidimensional spectroscopy is developing rapidly and its applications are spreading to biology and materials science. Edited by a recognized leader in the field and with contributions from top researchers, including experimentalists and theoreticians, this book presents the latest research methods and results and will serve as an excellent resource for other researchers.

Surface science and model catalysis with ionic liquid-modified materials.

Science.gov (United States)

Steinrück, H-P; Libuda, J; Wasserscheid, P; Cremer, T; Kolbeck, C; Laurin, M; Maier, F; Sobota, M; Schulz, P S; Stark, M

2011-06-17

Materials making use of thin ionic liquid (IL) films as support-modifying functional layer open up a variety of new possibilities in heterogeneous catalysis, which range from the tailoring of gas-surface interactions to the immobilization of molecularly defined reactive sites. The present report reviews recent progress towards an understanding of "supported ionic liquid phase (SILP)" and "solid catalysts with ionic liquid layer (SCILL)" materials at the microscopic level, using a surface science and model catalysis type of approach. Thin film IL systems can be prepared not only ex-situ, but also in-situ under ultrahigh vacuum (UHV) conditions using atomically well-defined surfaces as substrates, for example by physical vapor deposition (PVD). Due to their low vapor pressure, these systems can be studied in UHV using the full spectrum of surface science techniques. We discuss general strategies and considerations of this approach and exemplify the information available from complementary methods, specifically photoelectron spectroscopy and surface vibrational spectroscopy. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

European analytical column No. 36 from the Division of Analytical Chemistry (DAC) of the European Association for Chemical and Molecular Sciences (EuCheMS)

DEFF Research Database (Denmark)

Karlberg, Bo; Emons, Hendrik; Andersen, Jens Enevold Thaulov

2008-01-01

European analytical column no. 36 from the division of analytical chemistry (DAC) of the European association for chemical and molecular sciences (EuCheMS)......European analytical column no. 36 from the division of analytical chemistry (DAC) of the European association for chemical and molecular sciences (EuCheMS)...

Infrared Spectroscopy of Bilberry Extract Water-in-Oil Emulsions: Sensing the Water-Oil Interface

Directory of Open Access Journals (Sweden)

Johannes Kiefer

2016-04-01

Full Text Available Water-in-oil (w/o emulsions are of great interest in many areas of the life sciences, including food technology, bioprocess engineering, and pharmaceuticals. Such emulsions are complex multi-component systems and the molecular mechanisms which lead to a stable emulsion are yet to be fully understood. In this work, attenuated total reflection (ATR infrared (IR spectroscopy is applied to a series of w/o emulsions of an aqueous anthocyanin-rich bilberry extract dispersed in a medium chain triglyceride (MCT oil phase. The content of the emulsifier polyglycerin-polyricinoleat (PGPR has been varied systematically in order to investigate whether or not its concentration has an impact on the molecular stabilization mechanisms. The molecular stabilization is accessed by a careful analysis of the IR spectrum, where changes in the vibrational frequencies and signal strengths indicate alterations of the molecular environment at the water/oil interface. The results suggest that adding emulsifier in excess of 1% by weight does not lead to an enhanced stabilization of the emulsion.

Solid state spectroscopy by using of far-infrared synchrotron radiation

Energy Technology Data Exchange (ETDEWEB)

Nanba, Takao [Kobe Univ. (Japan). Faculty of Science

1996-07-01

If the spectroscopic system corresponding to the wavelength region required for experiment is installed, the light source with continuous wavelength is to be obtainable by synchrotron radiation. This report is that of the research on solid state spectroscopy using the ordinary incoherent synchrotron radiation which is obtained from the deflection electromagnet parts of electron storage ring. At present in the world, the facilities which can be utilized in far-infrared spectroscopy region are five, including the UVSOR of Molecular Science Research Institute in Japan. The optical arrangement of the measuring system of the UVSOR is shown. The spectrum distribution of the light passing through the pinholes with different diameter in the place of setting samples was compared in case of the UVSOR and a high pressure mercury lamp, and it was shown that synchrotron radiation has high luminance. The researches on solid state spectroscopy carried out in the above mentioned five facilities are enumerated. In this paper, the high pressure spectroscopic experiment which has been carried out at the UVSOR is reported. The observation of the phase transition of fine particles and the surface phonons of fine particles are described. As fine particle size became smaller, the critical pressure at which phase transition occurred was high. (K.I.)

Penning ionization processes studied by electron spectroscopy

International Nuclear Information System (INIS)

Yencha, A.J.

1978-01-01

The technique of measuring the kinetic energy of electrons ejected from atomic or molecular species as a result of collisional energy transfer between a metastable excited rare gas atom and an atom or molecule is known as Penning ionization spectroscopy. Like the analogous photoionization process of photoelectron spectroscopy, a considerable amount of information has been gained about the ionization potentials of numerous molecular systems. It is, in fact, through the combined analyses of photoelectron and Penning electron spectra that affords a probe of the particle-particle interactions that occur in the Penning process. In this paper a short survey of the phenomenon of Penning ionization, as studied by electron spectroscopy, will be presented as it pertains to the ionization processes of simple molecules by metastable excited atoms. (author)

Molecular and electronic structure of osmium complexes confined to Au(111) surfaces using a self-assembled molecular bridge

Energy Technology Data Exchange (ETDEWEB)

Llave, Ezequiel de la; Herrera, Santiago E.; Adam, Catherine; Méndez De Leo, Lucila P.; Calvo, Ernesto J.; Williams, Federico J., E-mail: fwilliams@qi.fcen.uba.ar [INQUIMAE-CONICET, Departamento de Química Inorgánica, Analítica y Química-Física, Facultad Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellón 2, Buenos Aires C1428EHA (Argentina)

2015-11-14

The molecular and electronic structure of Os(II) complexes covalently bonded to self-assembled monolayers (SAMs) on Au(111) surfaces was studied by means of polarization modulation infrared reflection absorption spectroscopy, photoelectron spectroscopies, scanning tunneling microscopy, scanning tunneling spectroscopy, and density functional theory calculations. Attachment of the Os complex to the SAM proceeds via an amide covalent bond with the SAM alkyl chain 40° tilted with respect to the surface normal and a total thickness of 26 Å. The highest occupied molecular orbital of the Os complex is mainly based on the Os(II) center located 2.2 eV below the Fermi edge and the LUMO molecular orbital is mainly based on the bipyridine ligands located 1.5 eV above the Fermi edge.

The interaction of 2-mercaptobenzimidazole with human serum albumin as determined by spectroscopy, atomic force microscopy and molecular modeling.

Science.gov (United States)

Li, Yuqin; Jia, Baoxiu; Wang, Hao; Li, Nana; Chen, Gaopan; Lin, Yuejuan; Gao, Wenhua

2013-04-01

The interaction of 2-mercaptobenzimidazole (MBI) with human serum albumin (HSA) was studied in vitro by equilibrium dialysis under normal physiological conditions. This study used fluorescence, ultraviolet-visible spectroscopy (UV-vis), Fourier transform infrared (FT-IR), circular dichroism (CD) and Raman spectroscopy, atomic force microscopy (AFM) and molecular modeling techniques. Association constants, the number of binding sites and basic thermodynamic parameters were used to investigate the quenching mechanism. Based on the fluorescence resonance energy transfer, the distance between the HSA and MBI was 2.495 nm. The ΔG(0), ΔH(0), and ΔS(0) values across temperature indicated that the hydrophobic interaction was the predominant binding Force. The UV, FT-IR, CD and Raman spectra confirmed that the HSA secondary structure was altered in the presence of MBI. In addition, the molecular modeling showed that the MBI-HSA complex was stabilized by hydrophobic forces, which resulted from amino acid residues. The AFM results revealed that the individual HSA molecule dimensions were larger after interaction with MBI. Overall, this study suggested a method for characterizing the weak intermolecular interaction. In addition, this method is potentially useful for elucidating the toxigenicity of MBI when it is combined with the biomolecular function effect, transmembrane transport, toxicological testing and other experiments. Copyright © 2012 Elsevier B.V. All rights reserved.

Nitro Stretch Probing of a Single Molecular Layer to Monitor Shock Compression with Picosecond Time-Resolution

Science.gov (United States)

Berg, Christopher; Lagutchev, Alexei; Fu, Yuanxi; Dlott, Dana

2011-06-01

To obtain maximum possible temporal resolution, laser-driven shock compression of a molecular monolayer was studied using vibrational spectroscopy. The stretching transitions of nitro groups bound to aromatic rings was monitored using a nonlinear coherent infrared spectroscopy termed sum-frequency generation, which produced high-quality signals from this very thin layer. To overcome the shock opacity problem, a novel polymer overcoat method allowed us to make the observation window (witness plate) a few micrometers thick. The high signal-to-noise ratios (>100:1) obtained via this spectroscopy allowed us to study detailed behavior of the shocked molecules. To help interpret these vibrational spectra, additional spectra were obtained under conditions of static pressures up to 10 GPa and static temperatures up to 1000 C. Consequently, this experiment represents a significant step in resolving molecular dynamics during shock compression and unloading with both high spatial and temporal resolution. Supported by the Stewardship Sciences Academic Alliance Program from the Carnegie-DOE Alliance Center under grant number DOE CIW 4-3253-13 and the US Air Force Office of Scientific Research under award number FAA9550-09-1-0163.

Mössbauer Spectroscopy Tutorial Book

CERN Document Server

Langouche, Guido

2013-01-01

Tutorials on Mössbauer Spectroscopy Since the discovery of the Mössbauer Effect many excellent books have been published for researchers and for doctoral and master level students.  However, there appears to be no textbook available for final year bachelor students, nor for people working in industry who have received only basic courses in classical mechanics, electromagnetism, quantum mechanics, chemistry and materials science.  The challenge of this book is to give an introduction to Mössbauer Spectroscopy for this level.  The ultimate goal of this book is to give this audience not only a scientific introduction to the technique, but also to demonstrate in an attractive way the power of Mössbauer Spectroscopy in many fields of science, in order to create interest among the readers in joining the community of Mössbauer spectroscopists.  This is particularly important at times where in many Mössbauer laboratories succession is at stake.

Journal of Chemical Sciences | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Chemical Sciences. SHWETA DHILLON. Articles written in Journal of Chemical Sciences. Volume 129 Issue 8 August 2017 pp 1277-1292 REGULAR ARTICLE. Theory for electrochemical impedance spectroscopy of heterogeneous electrode with distributed capacitance and charge transfer ...

Challenging the Science Curriculum Paradigm: Teaching Primary Children Atomic-Molecular Theory

Science.gov (United States)

Haeusler, Carole; Donovan, Jennifer

2017-11-01

Solutions to global issues demand the involvement of scientists, yet concern exists about retention rates in science as students pass through school into University. Young children are curious about science, yet are considered incapable of grappling with abstract and microscopic concepts such as atoms, sub-atomic particles, molecules and DNA. School curricula for primary (elementary) aged children reflect this by their limitation to examining only what phenomena are without providing any explanatory frameworks for how or why they occur. This research challenges the assumption that atomic-molecular theory is too difficult for young children, examining new ways of introducing atomic theory to 9 year olds and seeks to verify their efficacy in producing genuine learning in the participants. Early results in three cases in different schools indicate these novel methods fostered further interest in science, allowed diverse children to engage and learn aspects of atomic theory, and satisfied the children's desire for intellectual challenge. Learning exceeded expectations as demonstrated in the post-interview findings. Learning was also remarkably robust, as demonstrated in two schools 8 weeks after the intervention and, in one school, 1 year after their first exposure to ideas about atoms, elements and molecules.

Observation of molecular level behavior in molecular electronic junction device

Science.gov (United States)

Maitani, Masato

In this dissertation, I utilize AFM based scanning probe measurement and surface enhanced Raman scattering based vibrational spectroscopic analysis to directly characterize topographic, electronic, and chemical properties of molecules confined in the local area of M3 junction to elucidate the molecular level behavior of molecular junction electronic devices. In the introduction, the characterization of molecular electronic devices with different types of metal-molecule-metal (M3) structures based upon self-assembled monolayers (SAMs) is reviewed. A background of the characterization methods I use in this dissertation, conducting probe atomic force microscopy (cp-AFM) and surface enhanced Raman spectroscopy (SERS), is provided in chapter 1. Several attempts are performed to create the ideal top metal contacts on SAMs by metal vapor phase deposition in order to prevent the metal penetration inducing critical defects of the molecular electronic devices. The scanning probe microscopy (SPM), such as cp-AFM, contact mode (c-) AFM and non-contact mode (nc-) AFM, in ultra high vacuum conditions are utilized to study the process of the metal-SAM interface construction in terms of the correlation between the morphological and electrical properties including the metal nucleation and filament generation as a function of the functionalization of long-chain alkane thiolate SAMs on Au. In chapter 2, the nascent condensation process of vapor phase Al deposition on inert and reactive SAMs are studied by SPM. The results of top deposition, penetration, and filament generation of deposited Al are discussed and compared to the results previously observed by spectroscopic measurements. Cp-AFM was shown to provide new insights into Al filament formation which has not been observed by conventional spectroscopic analysis. Additionally, the electronic characteristics of individual Al filaments are measured. Chapter 3 reveals SPM characterization of Au deposition onto --COOH terminated SAMs

Journal of Chemical Sciences | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Chemical Sciences. AYOUB KANAANI. Articles written in Journal of Chemical Sciences. Volume 128 Issue 8 August 2016 pp 1211-1221 Regular Article. Synthesis, molecular structure, spectroscopic investigations and computational study of a potential molecular switch of 2-([1 ...

Committee on Atomic, Molecular, and Optical Sciences (CAMOS). Technical progress report ampersand continuation proposal, February 1, 1993--January 31, 1994

International Nuclear Information System (INIS)

Taylor, R.D.

1997-01-01

The Committee on Atomic, Molecular and Optical Sciences (CAMOS) of the National Research Council (NRC) is charged with monitoring the health of the field of atomic, molecular, and optical (AMO) science in the United States. Accordingly, the Committee identifies and examines both broad and specific issues affecting the field. Regular meetings, teleconferences, briefings from agencies and the scientific community, the formation of study panels to prepare reports, and special symposia are among the mechanisms used by the CAMOS to meet its charge. This progress report presents a review of CAMOS activities from February 1, 1993 to January 31, 1994. The details of prior activities are discussed in earlier progress reports. This report also includes the status of activities associated with the CAMOS study on the field that is being conducted by the Panel on the Future of Atomic, Molecular, and Optical Sciences (FAMOS). During the above period, CAMOS has continued to track and participate in, when requested, discussions on the health of the field. Much of the perspective of CAMOS has been presented in the recently-published report Research Briefing on Selected Opportunities in Atomic, Molecular, and Optical Sciences. That report has served as the basis for briefings to representatives of the federal government as well as the community-at-large. In keeping with its charge to monitor the health of the field, CAMOS launched a study designed to highlight future directions of the field

Interactive Multimodal Molecular Set – Designing Ludic Engaging Science Learning Content

DEFF Research Database (Denmark)

Thorsen, Tine Pinholt; Christiansen, Kasper Holm Bonde; Jakobsen Sillesen, Kristian

2014-01-01

This paper reports on an exploratory study investigating 10 primary school students’ interaction with an interactive multimodal molecular set fostering ludic engaging science learning content in primary schools (8th and 9th grade). The concept of the prototype design was to bridge the physical...... and virtual worlds with electronic tags and, through this, blend the familiarity of the computer and toys, to create a tool that provided a ludic approach to learning about atoms and molecules. The study was inspired by the participatory design and informant design methodologies and included design...

Use of UV-vis-NIR spectroscopy to monitor label-free interaction between molecular recognition elements and erythropoietin on a gold-coated polycarbonate platform.

Science.gov (United States)

Citartan, Marimuthu; Gopinath, Subash C B; Tominaga, Junji; Chen, Yeng; Tang, Thean-Hock

2014-08-01

Label-free-based detection is pivotal for real-time monitoring of biomolecular interactions and to eliminate the need for labeling with tags that can occupy important binding sites of biomolecules. One simplest form of label-free-based detection is ultraviolet-visible-near-infrared (UV-vis-NIR) spectroscopy, which measure changes in reflectivity as a means to monitor immobilization and interaction of biomolecules with their corresponding partners. In biosensor development, the platform used for the biomolecular interaction should be suitable for different molecular recognition elements. In this study, gold (Au)-coated polycarbonate was used as a platform and as a proof-of-concept, erythropoietin (EPO), a doping substance widely abused by the athletes was used as the target. The interaction of EPO with its corresponding molecular recognition elements (anti-EPO monoclonal antibody and anti-EPO DNA aptamer) is monitored by UV-vis-NIR spectroscopy. Prior to this, to show that UV-vis-NIR spectroscopy is a suitable method for measuring biomolecular interaction, the interaction between biotin and streptavidin was demonstrated via this strategy and reflectivity of this interaction decreased by 25%. Subsequent to this, interaction of the EPO with anti-EPO monoclonal antibody and anti-EPO DNA aptamer resulted in the decrease of reflectivity by 5% and 10%, respectively. The results indicated that Au-coated polycarbonate could be an ideal biosensor platform for monitoring biomolecular interactions using UV-vis-NIR spectroscopy. A smaller version of the Au-coated polycarbonate substrates can be derived from the recent set-up, to be applied towards detecting EPO abuse among atheletes. Copyright © 2014 Elsevier B.V. All rights reserved.

Polymorph characterization of active pharmaceutical ingredients (APIs) using low-frequency Raman spectroscopy.

Science.gov (United States)

Larkin, Peter J; Dabros, Marta; Sarsfield, Beth; Chan, Eric; Carriere, James T; Smith, Brian C

2014-01-01

Polymorph detection, identification, and quantitation in crystalline materials are of great importance to the pharmaceutical industry. Vibrational spectroscopic techniques used for this purpose include Fourier transform mid-infrared (FT-MIR) spectroscopy, Fourier transform near-infrared (FT-NIR) spectroscopy, Raman spectroscopy, and terahertz (THz) and far-infrared (FIR) spectroscopy. Typically, the fundamental molecular vibrations accessed using high-frequency Raman and MIR spectroscopy or the overtone and combination of bands in the NIR spectra are used to monitor the solid-state forms of active pharmaceutical ingredients (APIs). The local environmental sensitivity of the fundamental molecular vibrations provides an indirect probe of the long-range order in molecular crystals. However, low-frequency vibrational spectroscopy provides access to the lattice vibrations of molecular crystals and, hence, has the potential to more directly probe intermolecular interactions in the solid state. Recent advances in filter technology enable high-quality, low-frequency Raman spectra to be acquired using a single-stage spectrograph. This innovation enables the cost-effective collection of high-quality Raman spectra in the 200-10 cm(-1) region. In this study, we demonstrate the potential of low-frequency Raman spectroscopy for the polymorphic characterization of APIs. This approach provides several benefits over existing techniques, including ease of sampling and more intense, information-rich band structures that can potentially discriminate among crystalline forms. An improved understanding of the relationship between the crystalline structure and the low-frequency vibrational spectrum is needed for the more widespread use of the technique.

Behavior of beta-Amyloid 1-16 at the Air-Water Interface at Varying pH by Nonlinear Spectroscopy and Molecular Dynamics Simulations

Czech Academy of Sciences Publication Activity Database

Miller, A. E.; Petersen, P. B.; Hollars, C. H.; Saykally, R. J.; Heyda, Jan; Jungwirth, Pavel

2011-01-01

Roč. 115, č. 23 (2011), s. 5873-5880 ISSN 1089-5639 R&D Projects: GA MŠk LC512; GA ČR GA203/08/0114 Grant - others:NSF(US) 0650950 Institutional research plan: CEZ:AV0Z40550506 Keywords : beta-amyloid * air /water interface * SHG spectroscopy * molecular dynamics Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.946, year: 2011

In situ surface-enhanced Raman scattering spectroscopy exploring molecular changes of drug-treated cancer cell nucleus.

Science.gov (United States)

Liang, Lijia; Huang, Dianshuai; Wang, Hailong; Li, Haibo; Xu, Shuping; Chang, Yixin; Li, Hui; Yang, Ying-Wei; Liang, Chongyang; Xu, Weiqing

2015-02-17

Investigating the molecular changes of cancer cell nucleus with drugs treatment is crucial for the design of new anticancer drugs, the development of novel diagnostic strategies, and the advancement of cancer therapy efficiency. In order to better understand the action effects of drugs, accurate location and in situ acquisition of the molecular information of the cell nuclei are necessary. In this work, we report a microspectroscopic technique called dark-field and fluorescence coimaging assisted surface-enhanced Raman scattering (SERS) spectroscopy, combined with nuclear targeting nanoprobes, to in situ study Soma Gastric Cancer (SGC-7901) cell nuclei treated with two model drugs, e.g., DNA binder (Hoechst33342) and anticancer drug (doxorubicin, Dox) via spectral analysis at the molecular level. Nuclear targeting nanoprobes with an assembly structure of thiol-modified polyethylene glycol polymers (PEG) and nuclear localizing signal peptides (NLS) around gold nanorods (AuNRs) were prepared to achieve the amplified SERS signals of biomolecules in the cell nuclei. With the assistance of dark field/fluorescence imaging with simultaneous location, in situ SERS spectra in one cell nucleus were measured and analyzed to disclose the effects of Hoechst33342 and Dox on main biomolecules in the cell nuclei. The experimental results show that this method possesses great potential to investigate the targets of new anticancer drugs and the real-time monitoring of the dynamic changes of cells caused by exogenous molecules.

Raman Spectroscopy and its Application in Nanostructures

CERN Document Server

Zhang, Shu-Lin

2012-01-01

Raman Spectroscopy and its Application in Nanostructures is an original and timely contribution to a very active area of physics and materials science research. This book presents the theoretical and experimental phenomena of Raman spectroscopy, with specialized discussions on the physical fundamentals, new developments and main features in low-dimensional systems of Raman spectroscopy. In recent years physicists, materials scientists and chemists have devoted increasing attention to low-dimensional systems and as Raman spectroscopy can be used to study and analyse such materials as carbon nan

Rotational structure in molecular infrared spectra

CERN Document Server

di Lauro, Carlo

2013-01-01

Recent advances in infrared molecular spectroscopy have resulted in sophisticated theoretical and laboratory methods that are difficult to grasp without a solid understanding of the basic principles and underlying theory of vibration-rotation absorption spectroscopy. Rotational Structure in Molecular Infrared Spectra fills the gap between these recent, complex topics and the most elementary methods in the field of rotational structure in the infrared spectra of gaseous molecules. There is an increasing need for people with the skills and knowledge to interpret vibration-rotation spectra in many scientific disciplines, including applications in atmospheric and planetary research. Consequently, the basic principles of vibration-rotation absorption spectroscopy are addressed for contemporary applications. In addition to covering operational quantum mechanical methods, spherical tensor algebra, and group theoretical methods applied to molecular symmetry, attention is also given to phase conventions and their effe...

Gas in scattering media absorption spectroscopy - GASMAS

Science.gov (United States)

Svanberg, Sune

2008-09-01

An overview of the new field of Gas in Scattering Media Absorption Spectroscopy (GASMAS) is presented. GASMAS combines narrow-band diode-laser spectroscopy with diffuse media optical propagation. While solids and liquids have broad absorption features, free gas in pores and cavities in the material is characterized by sharp spectral signatures, typically 10,000 times sharper than those of the host material. Many applications in materials science, food packaging, pharmaceutics and medicine have been demonstrated. So far molecular oxygen and water vapour have been studied around 760 and 935 nm, respectively. Liquid water, an important constituent in many natural materials, such as tissue, has a low absorption at such wavelengths, allowing propagation. Polystyrene foam, wood, fruits, food-stuffs, pharmaceutical tablets, and human sinus cavities have been studied. Transport of gas in porous media can readily be studied by first immersing the material in, e.g., pure nitrogen, and then observing the rate at which normal air, containing oxygen, reinvades the material. The conductance of the sinus connective passages can be measured in this way by flushing the nasal cavity with nitrogen. Also other dynamic processes such as drying of materials can be studied. The techniques have also been extended to remote-sensing applications (LIDAR-GASMAS).

A proposal to establish an international network in molecular microbiology and genetic engineering for scientific cooperation and prevention of misuse of biological sciences in the framework of science for peace

International Nuclear Information System (INIS)

Becker, Y.

1998-01-01

The conference on 'Science and Technology for Construction of Peace' which was organized by the Landau Network Coordination Center and A. Volta Center for Scientific Culture dealt with conversion of military and technological capacities into sustainable civilian application. The ideas regarding the conversion of nuclear warheads into nuclear energy for civilian-use led to the idea that the extension of this trend of thought to molecular biology and genetic engineering, will be a useful contribution to Science for Peace. This idea of developing a Cooperation Network in Molecular Biology and Genetic Engineering that will function parallel to and with the Landau Network Coordination in the 'A. Volta' Center was discussed in the Second International Symposium on Science for Peace, Jerusalem, January 1997. It is the reason for the inclusion of the biological aspects in the deliberations of our Forum. It is hoped that the establishment of an international network in molecular biology and genetic engineering, similar to the Landau Network in physics, will support and achieve the decommissioning of biological weapons. Such a network in microbiology and genetic engineering will contribute to the elimination of biological weapons and to contributions to Science for Peace and to Culture of Peace activities of UNESCO. (author)

Alteration of biomacromolecule in corn by steam flaking in relation to biodegradation kinetics in ruminant, revealed with vibrational molecular spectroscopy

Science.gov (United States)

Xu, Ningning; Liu, Jianxin; Yu, Peiqiang

2018-02-01

Large scale of steam flaked corn has been used in dairy ration to maintain high milk production level. This study aimed to determine effects of steam flaking on processing-induced intrinsic molecular structure changes that were associated with rumen degradation kinetics and nutrients supply. The advanced vibrational molecular spectroscopy was applied to reveal the processing-induced intrinsic structure changes on a molecular basis. The rumen degradation kinetics and nutrient supply were determined using in situ approach in ruminant livestock system. Raw corn grain (RC) and steam flaked corn grain (SFC) were obtained from two different processing plants. The results showed that (1) Compared to RC, SFC had greater truly digestible non-fiber carbohydrate [tdNFC: 86.8 versus 78.0% dry matter (DM)], but lower truly digestible crude protein [tdCP: 7.7 versus 9.0% DM]. (2) The steam flaking increased (P < 0.01) rumen degradable DM (RDDM) and starch (RDSt), but decreased (P < 0.01) rumen degradable protein (RDP). (3) Molecular absorbance intensities of most carbohydrate biopolymers were greater in SFC (P < 0.01), but protein amides associated molecular spectral intensities were lower (P < 0.01) in SFC. (4). The molecular structure and nutrient interactive study showed that carbohydrate spectral intensities were positively (P < 0.10) associated with RDDM and RDSt and protein amide spectral intensities were positively (P < 0.10) associated with RDP. This results indicated that the steam flaking induced molecular structure changes had an interactive relationship with rumen degradation kinetics.

Two-dimensional infrared spectroscopy of vibrational polaritons.

Science.gov (United States)

Xiang, Bo; Ribeiro, Raphael F; Dunkelberger, Adam D; Wang, Jiaxi; Li, Yingmin; Simpkins, Blake S; Owrutsky, Jeffrey C; Yuen-Zhou, Joel; Xiong, Wei

2018-04-19

We report experimental 2D infrared (2D IR) spectra of coherent light-matter excitations--molecular vibrational polaritons. The application of advanced 2D IR spectroscopy to vibrational polaritons challenges and advances our understanding in both fields. First, the 2D IR spectra of polaritons differ drastically from free uncoupled excitations and a new interpretation is needed. Second, 2D IR uniquely resolves excitation of hybrid light-matter polaritons and unexpected dark states in a state-selective manner, revealing otherwise hidden interactions between them. Moreover, 2D IR signals highlight the impact of molecular anharmonicities which are applicable to virtually all molecular systems. A quantum-mechanical model is developed which incorporates both nuclear and electrical anharmonicities and provides the basis for interpreting this class of 2D IR spectra. This work lays the foundation for investigating phenomena of nonlinear photonics and chemistry of molecular vibrational polaritons which cannot be probed with traditional linear spectroscopy.

Molecular mechanism of extreme mechanostability in a pathogen adhesin.

Science.gov (United States)

Milles, Lukas F; Schulten, Klaus; Gaub, Hermann E; Bernardi, Rafael C

2018-03-30

High resilience to mechanical stress is key when pathogens adhere to their target and initiate infection. Using atomic force microscopy-based single-molecule force spectroscopy, we explored the mechanical stability of the prototypical staphylococcal adhesin SdrG, which targets a short peptide from human fibrinogen β. Steered molecular dynamics simulations revealed, and single-molecule force spectroscopy experiments confirmed, the mechanism by which this complex withstands forces of over 2 nanonewtons, a regime previously associated with the strength of a covalent bond. The target peptide, confined in a screwlike manner in the binding pocket of SdrG, distributes forces mainly toward the peptide backbone through an intricate hydrogen bond network. Thus, these adhesins can attach to their target with exceptionally resilient mechanostability, virtually independent of peptide side chains. Copyright © 2018 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

Quantum state-resolved gas/surface reaction dynamics probed by reflection absorption infrared spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Chen Li [Department of Dynamics at Surfaces, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, Goettingen (Germany); Ueta, Hirokazu; Beck, Rainer D. [Laboratoire de Chimie Physique Moleculaire, Ecole Polytechnique Federale de Lausanne (Switzerland); Bisson, Regis [Aix-Marseille Universite, PIIM, CNRS, UMR 7345, 13397 Marseille (France)

2013-05-15

We report the design and characterization of a new molecular-beam/surface-science apparatus for quantum state-resolved studies of gas/surface reaction dynamics combining optical state-specific reactant preparation in a molecular beam by rapid adiabatic passage with detection of surface-bound reaction products by reflection absorption infrared spectroscopy (RAIRS). RAIRS is a non-invasive infrared spectroscopic detection technique that enables online monitoring of the buildup of reaction products on the target surface during reactant deposition by a molecular beam. The product uptake rate obtained by calibrated RAIRS detection yields the coverage dependent state-resolved reaction probability S({theta}). Furthermore, the infrared absorption spectra of the adsorbed products obtained by the RAIRS technique provide structural information, which help to identify nascent reaction products, investigate reaction pathways, and determine branching ratios for different pathways of a chemisorption reaction. Measurements of the dissociative chemisorption of methane on Pt(111) with this new apparatus are presented to illustrate the utility of RAIRS detection for highly detailed studies of chemical reactions at the gas/surface interface.

Molecular Stirrers in Action

NARCIS (Netherlands)

Chen, Jiawen; Kistemaker, Jos C. M.; Robertus, Jort; Feringa, Ben L.

2014-01-01

A series of first-generation light-driven molecular motors with rigid substituents of varying length was synthesized to act as "molecular stirrers". Their rotary motion was studied by H-1 NMR and UV-vis absorption spectroscopy in a variety of solvents with different polarity and viscosity.

7th Czechoslovak spectroscopic conference and VIIIth CANAS (Conference on analytical atomic spectroscopy). Abstracts. Vol. 2

International Nuclear Information System (INIS)

1984-01-01

The conference on spectroscopy held in Ceske Budejovice on June 18-22, 1984, proceeded in three sessions: atomic spectroscopy, molecular spectroscopy and special spectroscopic techniques. In the molecular spectroscopy session, 81 papers were read of which 12 were inputted in INIS. The subject of inputted papers was the use of NMR for the analysis of organic compounds and for the study of radiation defects in semiconductors, and the use of infrared spectroscopy for the analysis of nuclear and irradiated materials. (J.P.)

EROSITA: AGN SCIENCE, BACKGROUND DETERMINATION, AND OPTICAL FOLLOW-UP SPECTROSCOPY

Directory of Open Access Journals (Sweden)

Thomas Boller

2013-12-01

Full Text Available More than 20 years after the highly impacting ROSAT all-sky survey in the soft X-ray spectral range, we are close to the next major X-ray all/sky surveys with eROSITA. eROSITA will be the primary instrument on-board the Russian “Spectrum–Roentgen–Gamma” (SRG satellite which will be launched from Baikonur in 2014 and placed in an L2 orbit. It will perform the first imaging all-sky survey in the medium energy X-ray range up to 10 keV with an unprecedented spectral and angular resolution. The eROSITA all sky X-ray survey will take place in a very different context than the ROSAT survey. There is now a wealth of complete, ongoing and planned surveys of the sky in broad range of wavelengths from the gamma, X-ray to the radio. A significant amount of science can be accomplished through the multi-frequency study of the eROSITA AGN and cluster sample, including optical confirmation and photometric redshift estimation of the eROSITA extended sources and AGNs. Optical spectroscopy has been, and will for the foreseeable future be, one of the main tools of astrophysics allowing studies of a large variety of astronomical objects over many fields of research. The fully capitalize on the eROSITA potential, a dedicated spectroscopic follow-up program is needed. 4MOST is the ideal instrument to secure the scientific success of the eROSITA X-ray survey and to overcome the small sample sizes together with selection biases that plagued past samples. The aim is to have the instrument commissioned in 2017, well matched to the data releases of eROSITA and Gaia. The design and implementation of the 4MOST facility simulator aimed to optimize the science output for eROSITA is described in necessary details.

Photoelectron spectroscopy via electronic spectroscopy of molecular ions

International Nuclear Information System (INIS)

Khan, Z.H.

1990-01-01

In this work, a new aspect of the correlation between optical and photoelectron spectra is discussed on the basis of which the first ionization potentials of condensed-ring aromatics can be estimated from certain features in the electronic spectra of their positive ions. Furthermore, it is noticed that the first IP's are very sensitive to molecular size as the latter's inclusion in the regression formulas improves the results considerably. Once the first ionization potential for a molecule is determined, its higher IP's may be computed if the lower-energy electronic bands for its cation are known. This procedure is especially useful for such systems whose uv photoelectron spectra are unknown. (author). 11 refs, 10 figs, 1 tab

XXII Conference on spectroscopy. Summaries of reports

International Nuclear Information System (INIS)

2001-01-01

XXII Conference on spectroscopy took place 8-12 October 2001 in Zvenigorod, Moscow region. The recent advantages in the field of atomic and molecular spectroscopy were discussed. The current methods for elemental spectra analysis were considered. They are based on both traditional atomic emission, adsorption and Raman spectroscopic techniques and on introduction of the mass spectroscopy with the high-temperature plasma atomizer. The particular attention was given the application of spectroscopic methods for plasma diagnostics and air pollution control [ru

Molecular Contamination on Anodized Aluminum Components of the Genesis Science Canister

Science.gov (United States)

Burnett, D. S.; McNamara, K. M.; Jurewicz, A.; Woolum, D.

2005-01-01

Inspection of the interior of the Genesis science canister after recovery in Utah, and subsequently at JSC, revealed a darkening on the aluminum canister shield and other canister components. There has been no such observation of film contamination on the collector surfaces, and preliminary spectroscopic ellipsometry measurements support the theory that the films observed on the anodized aluminum components do not appear on the collectors to any significant extent. The Genesis Science Team has made an effort to characterize the thickness and composition of the brown stain and to determine if it is associated with molecular outgassing.Detailed examination of the surfaces within the Genesis science canister reveals that the brown contamination is observed to varying degrees, but only on surfaces exposed in space to the Sun and solar wind hydrogen. In addition, the materials affected are primarily composed of anodized aluminum. A sharp line separating the sun and shaded portion of the thermal closeout panel is shown. This piece was removed from a location near the gold foil collector within the canister. Future plans include a reassembly of the canister components to look for large-scale patterns of contamination within the canister to aid in revealing the root cause.

Constraints on extra dimensions from precision molecular spectroscopy

NARCIS (Netherlands)

Salumbides, E.J.; Schellekens, A.N.; Gato-Rivera, B.; Ubachs, W.M.G.

2015-01-01

Accurate investigations of quantum-level energies in molecular systems are shown to provide a testing ground to constrain the size of compactified extra dimensions. This is made possible by recent progress in precision metrology with ultrastable lasers on energy levels in neutral molecular hydrogen

Human serum albumin interactions with C{sub 60} fullerene studied by spectroscopy, small-angle neutron scattering, and molecular dynamics simulations

Energy Technology Data Exchange (ETDEWEB)

Li, Song [Vanderbilt University, Department of Chemical and Biomolecular Engineering (United States); Zhao, Xiongce [NIDDK, National Institutes of Health (United States); Mo, Yiming [Institute of Agriculture, University of Tennessee (United States); Cummings, Peter T., E-mail: cummingspt@ornl.gov [Vanderbilt University, Department of Chemical and Biomolecular Engineering (United States); Heller, William T., E-mail: hellerwt@ornl.gov [Oak Ridge National Laboratory, Center for Structural Molecular Biology (United States)

2013-07-15

Concern about the toxicity of engineered nanoparticles, such as the prototypical nanomaterial C{sub 60} fullerene, continues to grow. While, evidence continues to mount that C{sub 60} and its derivatives may pose health hazards, the specific molecular interactions of these particles with biological macromolecules require further investigation. In this article, we report combined experimental and theoretical studies on the interaction of one of the most prevalent proteins in the human body, human serum albumin (HSA), with C{sub 60} in an aqueous environment. The C{sub 60}-HSA interaction was probed by circular dichroism (CD) spectroscopy, small-angle neutron scattering (SANS), and atomistic molecular dynamics (MD) simulations to understand C{sub 60}-driven changes in the structure of HSA in solution. The CD spectroscopy demonstrates that the secondary structure of the protein decreases in {alpha}-helical content in response to the presence of C{sub 60} (0.68 nm in diameter). Similarly, C{sub 60} produces subtle changes in the solution conformation of HSA (an 8.0 nm Multiplication-Sign 3.8 nm protein), as evidenced by the SANS data and MD simulations, but the data do not indicate that C{sub 60} changes the oligomerization state of the protein, such as by inducing aggregation. The results demonstrate that the interaction is not highly disruptive to the protein in a manner that would prevent it from performing its physiological function.

Resolving molecular vibronic structure using high-sensitivity two-dimensional electronic spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Bizimana, Laurie A.; Brazard, Johanna; Carbery, William P.; Gellen, Tobias; Turner, Daniel B., E-mail: dturner@nyu.edu [Department of Chemistry, New York University, 100 Washington Square East, New York, New York 10003 (United States)

2015-10-28

Coherent multidimensional optical spectroscopy is an emerging technique for resolving structure and ultrafast dynamics of molecules, proteins, semiconductors, and other materials. A current challenge is the quality of kinetics that are examined as a function of waiting time. Inspired by noise-suppression methods of transient absorption, here we incorporate shot-by-shot acquisitions and balanced detection into coherent multidimensional optical spectroscopy. We demonstrate that implementing noise-suppression methods in two-dimensional electronic spectroscopy not only improves the quality of features in individual spectra but also increases the sensitivity to ultrafast time-dependent changes in the spectral features. Measurements on cresyl violet perchlorate are consistent with the vibronic pattern predicted by theoretical models of a highly displaced harmonic oscillator. The noise-suppression methods should benefit research into coherent electronic dynamics, and they can be adapted to multidimensional spectroscopies across the infrared and ultraviolet frequency ranges.

Electron Paramagnetic Resonance Spectroscopy

Indian Academy of Sciences (India)

Home; Journals; Resonance – Journal of Science Education; Volume 20; Issue 11. Electron Paramagnetic Resonance Spectroscopy: Biological Applications. B G Hegde. General Article Volume 20 Issue 11 November 2015 pp 1017-1032. Fulltext. Click here to view fulltext PDF. Permanent link:

Probing Conditions at Ionized/Molecular Gas Interfaces With High Resolution Near-Infrared Spectroscopy

Science.gov (United States)

Kaplan, Kyle Franklin

2017-08-01

Regions of star formation and star death in our Galaxy trace the cycle of gas and dust in the interstellar medium (ISM). Gas in dense molecular clouds collapses to form stars, and stars at the end of their lives return the gas that made up their outer layers back out into the Galaxy. Hot stars generate copious amounts of ultraviolet photons which interact with the surrounding medium and dominate the energetics, ionization state, and chemistry of the gas. The interface where molecular gas is being dissociated into neutral atomic gas by far-UV photons from a nearby hot source is called a photodissociation or photon-dominated region (PDR). PDRs are found primarily in star forming regions where O and B stars serve as the source of UV photons, and in planetary nebulae where the hot core of the dying star acts as the UV source. The main target of this dissertation is molecular hydrogen (H2), the most abundant molecule in the Universe, made from hydrogen formed during the Big Bang. H2 makes up the overwhelming majority of molecules found in the ISM and in PDRs. Far-UV radiation absorbed by H2 will excite an electron in the molecule. The molecule then either dissociates ( 10% of the time; Field et al. 1966) or decays into excited rotational and vibrational ("rovibrational") levels of the electronic ground state. These excited rovibrational levels then decay via a radiative cascade to the ground rovibrational state (v = 0, J = 0), giving rise to a large number of transitions observable in emission from the mid-IR to the optical (Black & van Dishoeck, 1987). These transitions provide an excellent probe of the excitation and conditions within the gas. These transitions are also observed in warm H2, such as in shocks, where collisions excite H2 to higher rovibrational levels. High resolution near-infrared spectroscopy, with its ability to see through dust, and avoid telluric absorption and emission, serves as an effective tool to detect emission from ions, atoms, and molecules

Spectroscopy Division progress report (January 1991 to June 1992)

International Nuclear Information System (INIS)

Ahmad, S.A.; Kartha, V.B.

1993-01-01

The research and development activities of the Spectroscopy Division during the calendar year 1990-1992 are reported in the form of individual summaries. These are arranged under the headings: (1) analytical spectroscopy, (2) infrared and Raman spectroscopy, (3) atomic spectra, (4) molecular and electronic spectra, (5) laser spectroscopy (6) synchrotron, beam foil and plasma spectroscopy, (7) optics, (8) design, fabrication and workshop etc. The list of publications and papers presented at the various conferences, symposia etc. by the staff members of the Division during the report period is given at the end. (author). figs

Atoms, molecules and optical physics 2. Molecules and photons - Spectroscopy and collisions

Energy Technology Data Exchange (ETDEWEB)

Hertel, Ingolf V.; Schulz, Claus-Peter [Max-Born-Institut fuer Nichtlineare Optik und Kurzzeitspektroskopie im Forschungsverbund Berlin e.V. (Germany)

2015-09-01

This is the second volume of textbooks on atomic, molecular and optical physics, aiming at a comprehensive presentation of this highly productive branch of modern physics as an indispensable basis for many areas in physics and chemistry as well as in state of the art bio- and material-sciences. It primarily addresses advanced students (including PhD students), but in a number of selected subject areas the reader is lead up to the frontiers of present research. Thus even the active scientist is addressed. This volume 2 introduces lasers and quantum optics, while the main focus is on the structure of molecules and their spectroscopy, as well as on collision physics as the continuum counterpart to bound molecular states. The emphasis is always on the experiment and its interpretation, while the necessary theory is introduced from this perspective in a compact and occasionally somewhat heuristic manner, easy to follow even for beginners.

The laboratory technology of discrete molecular separation: the historical development of gel electrophoresis and the material epistemology of biomolecular science, 1945-1970.

Science.gov (United States)

Chiang, Howard Hsueh-hao

2009-01-01

Preparative and analytical methods developed by separation scientists have played an important role in the history of molecular biology. One such early method is gel electrophoresis, a technique that uses various types of gel as its supporting medium to separate charged molecules based on size and other properties. Historians of science, however, have only recently begun to pay closer attention to this material epistemological dimension of biomolecular science. This paper substantiates the historiographical thread that explores the relationship between modern laboratory practice and the production of scientific knowledge. It traces the historical development of gel electrophoresis from the mid-1940s to the mid-1960s, with careful attention to the interplay between technical developments and disciplinary shifts, especially the rise of molecular biology in this time-frame. Claiming that the early 1950s marked a decisive shift in the evolution of electrophoretic methods from moving boundary to zone electrophoresis, I reconstruct various trajectories in which scientists such as Oliver Smithies sought out the most desirable solid supporting medium for electrophoretic instrumentation. Biomolecular knowledge, I argue, emerged in part from this process of seeking the most appropriate supporting medium that allowed for discrete molecular separation and visualization. The early 1950s, therefore, marked not only an important turning point in the history of separation science, but also a transformative moment in the history of the life sciences as the growth of molecular biology depended in part on the epistemological access to the molecular realm available through these evolving technologies.

Bulletin of Materials Science | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Bulletin of Materials Science. B P Singh. Articles written in Bulletin of Materials Science. Volume 23 Issue 1 February 2000 pp 11-16 Molecular Magnets. Synthesis and magnetic properties of one-dimensional metal oxalate networks as molecular-based magnets · B P Singh B Singh · More Details Abstract ...

Elementary Steps of Faujasite Formation Followed by in Situ Spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Prodinger, Sebastian [Institute; Vjunov, Aleksei [Institute; Hu, Jian Zhi [Institute; Fulton, John L. [Institute; Camaioni, Donald M. [Institute; Derewinski, Miroslaw A. [Institute; Lercher, Johannes A. [Institute; Department

2018-01-24

Ex situ and in situ spectroscopy was used to identify the kinetics of processes during the formation of the faujasite (FAU) zeolite lattice from a hydrous gel. Using solid-state 27Al MAS NMR, the autocatalytic transformation from the amorphous gel into the crystalline material was monitored. Al-XANES shows that most Al already adopts a tetrahedral coordination in the X-ray-amorphous aluminosilicate at the beginning of the induction period, which hardly changes throughout the rest of the synthesis. Using 23Na NMR spectroscopy, environments in the growing zeolite crystal were identified and used to define the processes in the stepwise formation of the zeolite lattice. The end of the induction period was accompanied by a narrowing of the 27Al and 23Na MAS NMR peak widths, indicating the increased long-range order. The experiments show conclusively that the formation of faujasite occurs via the continuous formation and subsequent condensation of intermediary sodalite-like units that constitute the key building block of the zeolite. Acknowledgement The authors thank T. Huthwelker for assistance with XAFS experiment setup at the Swiss Light Source (PSI, Switzerland). Further, we would like to acknowledge V. Shutthanandan and B.W. Arey for performing Helium ion microscopy as well as Z. Zhao, N.R. Jaeger, M. Weng, C. Wan and M. Hu for aiding in the NMR experimental procedure. T. Varga is acknowledged for his help with the capillary XRD. A.V., D.M.C., J.H., J.L.F and J.A.L. were supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences. S.P. and M.A.D. acknowledge support by the Materials Synthesis and Simulation Across Scales (MS3 Initiative) conducted under Laboratory Directed Research & Development Program at PNNL. The in situ NMR experiments were supported by the U. S. Department of Energy (DOE), Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Biosciences and Geosciences. Part of the research

AXSIS: Exploring the frontiers in attosecond X-ray science, imaging and spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Kärtner, F.X., E-mail: franz.kaertner@cfel.de [Center for Free-Electron Laser Science, Hamburg (Germany); Institute for Experimental Physics, University of Hamburg, Hamburg (Germany); The Hamburg Center for Ultrafast Imaging, Hamburg (Germany); DESY, Hamburg (Germany); Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA (United States); Ahr, F. [Center for Free-Electron Laser Science, Hamburg (Germany); Institute for Experimental Physics, University of Hamburg, Hamburg (Germany); DESY, Hamburg (Germany); Max Planck Institute for the Structure and Dynamics of Matter, Hamburg (Germany); Calendron, A.-L. [Center for Free-Electron Laser Science, Hamburg (Germany); Institute for Experimental Physics, University of Hamburg, Hamburg (Germany); The Hamburg Center for Ultrafast Imaging, Hamburg (Germany); DESY, Hamburg (Germany); Çankaya, H. [Center for Free-Electron Laser Science, Hamburg (Germany); The Hamburg Center for Ultrafast Imaging, Hamburg (Germany); DESY, Hamburg (Germany); Carbajo, S. [Center for Free-Electron Laser Science, Hamburg (Germany); Institute for Experimental Physics, University of Hamburg, Hamburg (Germany); DESY, Hamburg (Germany); Chang, G.; Cirmi, G. [Center for Free-Electron Laser Science, Hamburg (Germany); The Hamburg Center for Ultrafast Imaging, Hamburg (Germany); DESY, Hamburg (Germany); Dörner, K. [Center for Free-Electron Laser Science, Hamburg (Germany); DESY, Hamburg (Germany); Dorda, U. [DESY, Hamburg (Germany); Fallahi, A. [Center for Free-Electron Laser Science, Hamburg (Germany); DESY, Hamburg (Germany); Hartin, A. [Center for Free-Electron Laser Science, Hamburg (Germany); Institute for Experimental Physics, University of Hamburg, Hamburg (Germany); DESY, Hamburg (Germany); Hemmer, M. [Center for Free-Electron Laser Science, Hamburg (Germany); DESY, Hamburg (Germany); and others

2016-09-01

X-ray crystallography is one of the main methods to determine atomic-resolution 3D images of the whole spectrum of molecules ranging from small inorganic clusters to large protein complexes consisting of hundred-thousands of atoms that constitute the macromolecular machinery of life. Life is not static, and unravelling the structure and dynamics of the most important reactions in chemistry and biology is essential to uncover their mechanism. Many of these reactions, including photosynthesis which drives our biosphere, are light induced and occur on ultrafast timescales. These have been studied with high time resolution primarily by optical spectroscopy, enabled by ultrafast laser technology, but they reduce the vast complexity of the process to a few reaction coordinates. In the AXSIS project at CFEL in Hamburg, funded by the European Research Council, we develop the new method of attosecond serial X-ray crystallography and spectroscopy, to give a full description of ultrafast processes atomically resolved in real space and on the electronic energy landscape, from co-measurement of X-ray and optical spectra, and X-ray diffraction. This technique will revolutionize our understanding of structure and function at the atomic and molecular level and thereby unravel fundamental processes in chemistry and biology like energy conversion processes. For that purpose, we develop a compact, fully coherent, THz-driven attosecond X-ray source based on coherent inverse Compton scattering off a free-electron crystal, to outrun radiation damage effects due to the necessary high X-ray irradiance required to acquire diffraction signals. This highly synergistic project starts from a completely clean slate rather than conforming to the specifications of a large free-electron laser (FEL) user facility, to optimize the entire instrumentation towards fundamental measurements of the mechanism of light absorption and excitation energy transfer. A multidisciplinary team formed by laser

Basic Principles of Spectroscopy

Science.gov (United States)

Penner, Michael H.

Spectroscopy deals with the production, measurement, and interpretation of spectra arising from the interaction of electromagnetic radiation with matter. There are many different spectroscopic methods available for solving a wide range of analytical problems. The methods differ with respect to the species to be analyzed (such as molecular or atomic spectroscopy), the type of radiation-matter interaction to be monitored (such as absorption, emission, or diffraction), and the region of the electromagnetic spectrum used in the analysis. Spectroscopic methods are very informative and widely used for both quantitative and qualitative analyses. Spectroscopic methods based on the absorption or emission of radiation in the ultraviolet (UV), visible (Vis), infrared (IR), and radio (nuclear magnetic resonance, NMR) frequency ranges are most commonly encountered in traditional food analysis laboratories. Each of these methods is distinct in that it monitors different types of molecular or atomic transitions. The basis of these transitions is explained in the following sections.

Spectroscopy Division Progress report for 1977-79

International Nuclear Information System (INIS)

Saksena, G.D.; Naik, R.C.

1979-01-01

An account of the activities of the Spectroscopy Division of the Bhabha Atomic Research Centre, Bombay, covering the period 1977-79 is given. The activities broadly cover the areas of spectrochemical analysis, research and development programmes in the fields of atomic and molecular spectroscopy and design and fabrication of high precision optical instruments and electronic components required for the above programmes. (K.B.)

Multidimensional high harmonic spectroscopy

International Nuclear Information System (INIS)

Bruner, Barry D; Soifer, Hadas; Shafir, Dror; Dudovich, Nirit; Serbinenko, Valeria; Smirnova, Olga

2015-01-01

High harmonic generation (HHG) has opened up a new frontier in ultrafast science where attosecond time resolution and Angstrom spatial resolution are accessible in a single measurement. However, reconstructing the dynamics under study is limited by the multiple degrees of freedom involved in strong field interactions. In this paper we describe a new class of measurement schemes for resolving attosecond dynamics, integrating perturbative nonlinear optics with strong-field physics. These approaches serve as a basis for multidimensional high harmonic spectroscopy. Specifically, we show that multidimensional high harmonic spectroscopy can measure tunnel ionization dynamics with high precision, and resolves the interference between multiple ionization channels. In addition, we show how multidimensional HHG can function as a type of lock-in amplifier measurement. Similar to multi-dimensional approaches in nonlinear optical spectroscopy that have resolved correlated femtosecond dynamics, multi-dimensional high harmonic spectroscopy reveals the underlying complex dynamics behind attosecond scale phenomena. (paper)

Super-Resolution Molecular and Functional Imaging of Nanoscale Architectures in Life and Materials Science

KAUST Repository

Habuchi, Satoshi

2014-06-12

Super-resolution (SR) fluorescence microscopy has been revolutionizing the way in which we investigate the structures, dynamics, and functions of a wide range of nanoscale systems. In this review, I describe the current state of various SR fluorescence microscopy techniques along with the latest developments of fluorophores and labeling for the SR microscopy. I discuss the applications of SR microscopy in the fields of life science and materials science with a special emphasis on quantitative molecular imaging and nanoscale functional imaging. These studies open new opportunities for unraveling the physical, chemical, and optical properties of a wide range of nanoscale architectures together with their nanostructures and will enable the development of new (bio-)nanotechnology.

Applications of core level spectroscopy to adsorbates

International Nuclear Information System (INIS)

Nilsson, Anders

2002-01-01

In the following review different applications of core-level spectroscopy to atomic and molecular adsorbates will be shown. Core-holes are created through core-level ionization and X-ray absorption processes and the core-hole decays by radiant and non-radiant processes. This forms the basis for X-ray photoelectron spectroscopy, X-ray absorption spectroscopy, Auger electron spectroscopy and X-ray emission spectroscopy. We will demonstrate how we can use the different methods to obtain information about the chemical state, local geometric structure, nature of chemical bonding and dynamics in electron transfer processes. The adsorption of N 2 and CO on Ni(100) will be used as prototype systems for chemisorption while N 2 on graphite and Ar on Pt for physisorption

Photoelectron spectroscopy of self-assembled monolayers of molecular switches on noble metal surfaces; Photoelektronenspektroskopie selbstorganisierter Adsorbatschichten aus molekularen Schaltern auf Edelmetalloberflaechen

Energy Technology Data Exchange (ETDEWEB)

Heinemann, Nils

2012-09-12

Self-assembled monolayers (SAMs) of butanethiolate (C4) on single crystalline Au(111) surfaces were prepared by adsorption from solution. The thermally activated desorption behaviour of the C4 molecules from the gold substrate was examined by qualitative thermal desorption measurements (TDM), through this a desorption temperature T{sub Des}=473 K could be determined. With this knowledge, it was possible to produce samples of very good surface quality, by thermal treatment T{sub Sample}spectroscopy of C4/Au was on the samples of the p x {radical}(3) phase using two-photon photoemission spectroscopy (2PPE). The spectra revealed clear signatures of two unoccupied resonance states at energies E-E{sub F}=3.7 eV and 3.9 eV. The low-energy state was assigned to the characteristic {sigma}*-resonance associated with the Au-S bond of the thiolate. The energy of the other resonance state agreed well with an interface state reported before for SAMs of an other alkanethiol on Au(111) in a densely packed phase. Furthermore the 2PPE data indicated that the high quality of the ex situ prepared SAMs supported the formation of image potential states. The reversible photo- and thermally activated isomerization of the molecular switch 3-(4-(4-Hexyl-phenylazo)-phenoxy)-propane-1-thiol (ABT), deposited by self-assembly from solution on Au(111), was examined using laser-based photoelectron spectroscopy. Differences in the molecular dipole moment characteristic for the trans and the cis isomer of ABT were observed via changes in the sample work function, accessible by detection of the threshold energy for photoemission. A quantitative

Infrared (1-12 μm) atomic and molecular emission signatures from energetic materials using laser-induced breakdown spectroscopy

Science.gov (United States)

Kumi Barimah, E.; Hömmerich, U.; Brown, E.; Yang, C. S.-C.; Trivedi, S. B.; Jin, F.; Wijewarnasuriya, P. S.; Samuels, A. C.; Snyder, A. P.

2013-05-01

Laser-induced breakdown spectroscopy (LIBS) is a powerful analytical technique to detect the elemental composition of solids, liquids, and gases in real time. For example, recent advances in UV-VIS LIBS have shown great promise for applications in chemical, biological, and explosive sensing. The extension of conventional UVVIS LIBS to the near-IR (NIR), mid-IR (MIR) and long wave infrared (LWIR) regions (~1-12 μm) offers the potential to provide additional information due to IR atomic and molecular signatures. In this work, a Q-switched Nd: YAG laser operating at 1064 nm was employed as the excitation source and focused onto several chlorate and nitrate compounds including KClO3, NaClO3, KNO3, and NaNO3 to produce intense plasma at the target surface. IR LIBS studies on background air, KCl , and NaCl were also included for comparison. All potassium and sodium containing samples revealed narrow-band, atomic-like emissions assigned to transitions of neutral alkali-metal atoms in accordance with the NIST atomic spectra database. In addition, first evidence of broad-band molecular LIBS signatures from chlorate and nitrate compounds were observed at ~10 μm and ~7.3 μm, respectively. The observed molecular emissions showed strong correlation with FTIR absorption spectra of the investigated materials.

Formation and stability of .beta.-structure in biodegradable ultra-high-molecular-weight poly(3-hydroxybutyrate) by infrared, Raman, and quantum chemical calculation studies

Czech Academy of Sciences Publication Activity Database

Murakami, R.; Sato, H.; Dybal, Jiří; Iwata, T.; Ozaki, Y.

2007-01-01

Roč. 48, č. 9 (2007), s. 2672-2680 ISSN 0032-3861 R&D Projects: GA ČR GA203/05/0425 Grant - others:Ministry of Education, Culture, Sports, Science and Technology(JP) 18750107 Institutional research plan: CEZ:AV0Z40500505 Keywords : ultra-high-molecular-weight poly(hydroxybutyrate) * .beta.-form * Raman spectroscopy Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.065, year: 2007

Three-dimensional hybrid silicon nanostructures for surface enhanced Raman spectroscopy based molecular detection

Science.gov (United States)

Vendamani, V. S.; Nageswara Rao, S. V. S.; Venugopal Rao, S.; Kanjilal, D.; Pathak, A. P.

2018-01-01

Three-dimensional silver nanoparticles decorated vertically aligned Si nanowires (Si NWs) are effective surface-enhanced Raman spectroscopy (SERS) substrates for molecular detection at low concentration levels. The length of Si NWs prepared by silver assisted electroless etching is increased with an increase in etching time, which resulted in the reduced optical reflection in the visible region. These substrates were tested and optimized by measuring the Raman spectrum of standard dye Rhodamine 6G (R6G) of 10 nM concentration. Further, effective SERS enhancements of ˜105 and ˜104 were observed for the cytosine protein (concentration of 50 μM) and ammonium perchlorate (oxidizer used in explosives composition with a concentration of 10 μM), respectively. It is established that these three-dimensional SERS substrates yielded considerably higher enhancement factors for the detection of R6G when compared to previous reports. The sensitivity can further be increased and optimized since the Raman enhancement was found to increase with an increase in the density of silver nanoparticles decorated on the walls of Si NWs.

Operation of micro and molecular machines: a new concept with its origins in interface science.

Science.gov (United States)

Ariga, Katsuhiko; Ishihara, Shinsuke; Izawa, Hironori; Xia, Hong; Hill, Jonathan P

2011-03-21

A landmark accomplishment of nanotechnology would be successful fabrication of ultrasmall machines that can work like tweezers, motors, or even computing devices. Now we must consider how operation of micro- and molecular machines might be implemented for a wide range of applications. If these machines function only under limited conditions and/or require specialized apparatus then they are useless for practical applications. Therefore, it is important to carefully consider the access of functionality of the molecular or nanoscale systems by conventional stimuli at the macroscopic level. In this perspective, we will outline the position of micro- and molecular machines in current science and technology. Most of these machines are operated by light irradiation, application of electrical or magnetic fields, chemical reactions, and thermal fluctuations, which cannot always be applied in remote machine operation. We also propose strategies for molecular machine operation using the most conventional of stimuli, that of macroscopic mechanical force, achieved through mechanical operation of molecular machines located at an air-water interface. The crucial roles of the characteristics of an interfacial environment, i.e. connection between macroscopic dimension and nanoscopic function, and contact of media with different dielectric natures, are also described.

Basic Energy Sciences Program Update

Energy Technology Data Exchange (ETDEWEB)

None, None

2016-01-04

The U.S. Department of Energy’s (DOE) Office of Basic Energy Sciences (BES) supports fundamental research to understand, predict, and ultimately control matter and energy at the electronic, atomic, and molecular levels to provide the foundations for new energy technologies and to support DOE missions in energy, environment, and national security. The research disciplines covered by BES—condensed matter and materials physics, chemistry, geosciences, and aspects of physical biosciences— are those that discover new materials and design new chemical processes. These disciplines touch virtually every aspect of energy resources, production, conversion, transmission, storage, efficiency, and waste mitigation. BES also plans, constructs, and operates world-class scientific user facilities that provide outstanding capabilities for imaging and spectroscopy, characterizing materials of all kinds ranging from hard metals to fragile biological samples, and studying the chemical transformation of matter. These facilities are used to correlate the microscopic structure of materials with their macroscopic properties and to study chemical processes. Such experiments provide critical insights to electronic, atomic, and molecular configurations, often at ultrasmall length and ultrafast time scales.

Ab Initio Molecular Dynamics of Uranium Incorporated in Goethite (α-FeOOH): Interpretation of X-ray Absorption Spectroscopy of Trace Polyvalent Metals.

Science.gov (United States)

Kerisit, Sebastien; Bylaska, Eric J; Massey, Michael S; McBriarty, Martin E; Ilton, Eugene S

2016-11-21

Incorporation of economically or environmentally consequential polyvalent metals into iron (oxyhydr)oxides has applications in environmental chemistry, remediation, and materials science. A primary tool for characterizing the local coordination environment of such metals, and therefore building models to predict their behavior, is extended X-ray absorption fine structure spectroscopy (EXAFS). Accurate structural information can be lacking yet is required to constrain and inform data interpretation. In this regard, ab initio molecular dynamics (AIMD) was used to calculate the local coordination environment of minor amounts of U incorporated in the structure of goethite (α-FeOOH). U oxidation states (VI, V, and IV) and charge compensation schemes were varied. Simulated trajectories were used to calculate the U L III -edge EXAFS function and fit experimental EXAFS data for U incorporated into goethite under reducing conditions. Calculations that closely matched the U EXAFS of the well-characterized mineral uraninite (UO 2 ), and constrained the S 0 2 parameter to be 0.909, validated the approach. The results for the U-goethite system indicated that U(V) substituted for structural Fe(III) in octahedral uranate coordination. Charge balance was achieved by the loss of one structural proton coupled to addition of one electron into the solid (-1 H + , +1 e - ). The ability of AIMD to model higher energy states thermally accessible at room temperature is particularly relevant for protonated systems such as goethite, where proton transfers between adjacent octahedra had a dramatic effect on the calculated EXAFS. Vibrational effects as a function of temperature were also estimated using AIMD, allowing separate quantification of thermal and configurational disorder. In summary, coupling AIMD structural modeling and EXAFS experiments enables modeling of the redox behavior of polyvalent metals that are incorporated in conductive materials such as iron (oxyhydr)oxides, with

Single Molecule Spectroscopy of Electron Transfer

International Nuclear Information System (INIS)

Holman, Michael; Zang, Ling; Liu, Ruchuan; Adams, David M.

2009-01-01

The objectives of this research are threefold: (1) to develop methods for the study electron transfer processes at the single molecule level, (2) to develop a series of modifiable and structurally well defined molecular and nanoparticle systems suitable for detailed single molecule/particle and bulk spectroscopic investigation, (3) to relate experiment to theory in order to elucidate the dependence of electron transfer processes on molecular and electronic structure, coupling and reorganization energies. We have begun the systematic development of single molecule spectroscopy (SMS) of electron transfer and summaries of recent studies are shown. There is a tremendous need for experiments designed to probe the discrete electronic and molecular dynamic fluctuations of single molecules near electrodes and at nanoparticle surfaces. Single molecule spectroscopy (SMS) has emerged as a powerful method to measure properties of individual molecules which would normally be obscured in ensemble-averaged measurement. Fluctuations in the fluorescence time trajectories contain detailed molecular level statistical and dynamical information of the system. The full distribution of a molecular property is revealed in the stochastic fluctuations, giving information about the range of possible behaviors that lead to the ensemble average. In the case of electron transfer, this level of understanding is particularly important to the field of molecular and nanoscale electronics: from a device-design standpoint, understanding and controlling this picture of the overall range of possible behaviors will likely prove to be as important as designing ia the ideal behavior of any given molecule.

Journal of Chemical Sciences | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Chemical Sciences. V V Namboodiri. Articles written in Journal of Chemical Sciences. Volume 124 Issue 1 January 2012 pp 177-186. Basic principles of ultrafast Raman loss spectroscopy · N K Rai A Y Lakshmanna V V Namboodiri S Umapathy · More Details Abstract Fulltext PDF. When a light ...

Molecular environment of iodine in naturally iodinated humic substances: Insight from X-ray absorption spectroscopy

International Nuclear Information System (INIS)

Schlegel, Michel L.; Mercier-Bion, Florence; Barre, Nicole; Reiller, Pascal; Moulin, Valerie

2006-01-01

The molecular environment of iodine in reference inorganic and organic compounds, and in dry humic and fulvic acids (HAs and FAs) extracted from subsurface and deep aquifers was probed by iodine L-3-edge X-ray absorption spectroscopy. The X-ray absorption near-edge structure (XANES) of iodine spectra from HAs and FAs resembled those of organic references and displayed structural features consistent with iodine forming covalent bonds with organic molecules. Simulation of XANES spectra by linear combination of reference spectra suggested the predominance of iodine forming covalent bonds to aromatic rings (aromatic-bound iodine). Comparison of extended X-ray absorption fine structure (EXAFS) spectra of reference and samples further showed that iodine was surrounded by carbon shells at distances comparable to those for references containing aromatic-bound iodine. Quantitative analysis of EXAFS spectra indicated that iodine was bound to about one carbon at a distance d(I-C) of 2.01(4)-2.04(9) angstrom, which was comparable to the distances observed for aromatic-bound iodine in references (1.99(1)-2.07(6) angstrom), and significantly shorter than that observed for aliphatic-bound iodine (2.15(2)-2.16(2) angstrom). These results are in agreement with previous conclusions from X-ray photoelectron spectroscopy and from electro-spray ionization mass spectrometry. These results collectively suggest that the aromatic-bound iodine is stable in the various aquifers of this study. (authors)

Laser magnetic resonance spectroscopy

International Nuclear Information System (INIS)

Ferrari, C.A.

1985-01-01

The technique of laser resonance magnetic resonance allows one to study the high-resolution spectroscopy of transient paramagnetic species, viz, atoms, radicals, and molecular ions. This article is a brief exposition of the method, describing the principles, instrumentation and applicability of the IR and FIR-LMR and shows results of HF + . (Author) [pt

Adaptive real-time dual-comb spectroscopy

OpenAIRE

Ideguchi, Takuro; Poisson, Antonin; Guelachvili, Guy; Picque, Nathalie; Hansch, Theodor W.

2014-01-01

The spectrum of a laser frequency comb consists of several hundred thousand equally spaced lines over a broad spectral bandwidth. Such frequency combs have revolutionized optical frequency metrology and they now hold much promise for significant advances in a growing number of applications including molecular spectroscopy. Despite an intriguing potential for the measurement of molecular spectra spanning tens of nanometres within tens of microseconds at Doppler-limited resolution, the developm...

14th international symposium on molecular beams

Energy Technology Data Exchange (ETDEWEB)

1992-09-01

This report discusses research being conducted with molecular beams. The general topic areas are as follows: Clusters I; reaction dynamics; atomic and molecular spectroscopy; clusters II; new techniques; photodissociation & dynamics; and surfaces.

14th international symposium on molecular beams

Energy Technology Data Exchange (ETDEWEB)

1992-01-01

This report discusses research being conducted with molecular beams. The general topic areas are as follows: Clusters I; reaction dynamics; atomic and molecular spectroscopy; clusters II; new techniques; photodissociation dynamics; and surfaces.

Excited state dynamics & optical control of molecular motors

Science.gov (United States)

Wiley, Ted; Sension, Roseanne

2014-03-01

Chiral overcrowded alkenes are likely candidates for light driven rotary molecular motors. At their core, these molecular motors are based on the chromophore stilbene, undergoing ultrafast cis/trans photoisomerization about their central double bond. Unlike stilbene, the photochemistry of molecular motors proceeds in one direction only. This unidirectional rotation is a result of helicity in the molecule induced by steric hindrance. However, the steric hindrance which ensures unidirectional excited state rotation, has the unfortunate consequence of producing large ground state barriers which dramatically decrease the overall rate of rotation. These molecular scale ultrafast motors have only recently been studied by ultrafast spectroscopy. Our lab has studied the photochemistry and photophysics of a ``first generation'' molecular motor with UV-visible transient absorption spectroscopy. We hope to use optical pulse shaping to enhance the efficiency and turnover rate of these molecular motors.

Molecular dynamics of amorphous pharmaceutical fenofibrate studied by broadband dielectric spectroscopy

Directory of Open Access Journals (Sweden)

U. Sailaja

2016-06-01

Full Text Available Fenofibrate is mainly used to reduce cholesterol level in patients at risk of cardiovascular disease. Thermal transition study with the help of differential scanning calorimetry (DSC shows that the aforesaid active pharmaceutical ingredient (API is a good glass former. Based on our DSC study, the molecular dynamics of this API has been carried out by broadband dielectric spectroscopy (BDS covering wide temperature and frequency ranges. Dielectric measurements of amorphous fenofibrate were performed after its vitrification by fast cooling from a few degrees above the melting point (Tm=354.11 K to deep glassy state. The sample does not show any crystallization tendency during cooling and reaches the glassy state. The temperature dependence of the structural relaxation has been fitted by single Vogel–Fulcher–Tamman (VFT equation. From VFT fit, glass transition temperature (Tg was estimated as 250.56 K and fragility (m was determined as 94.02. This drug is classified as a fragile glass former. Deviations of experimental data from Kohlrausch–Williams–Watts (KWW fits on high-frequency flank of α-peak indicate the presence of an excess wing in fenofibrate. Based on Ngai׳s coupling model, we identified the excess wing as true Johari–Goldstein (JG process. Below the glass transition temperature one can clearly see a secondary relaxation (γ with an activation energy of 32.67 kJ/mol.

Molecular Nutrition Research—The Modern Way Of Performing Nutritional Science

Directory of Open Access Journals (Sweden)

Arild C. Rustan

2012-12-01

Full Text Available In spite of amazing progress in food supply and nutritional science, and a striking increase in life expectancy of approximately 2.5 months per year in many countries during the previous 150 years, modern nutritional research has a great potential of still contributing to improved health for future generations, granted that the revolutions in molecular and systems technologies are applied to nutritional questions. Descriptive and mechanistic studies using state of the art epidemiology, food intake registration, genomics with single nucleotide polymorphisms (SNPs and epigenomics, transcriptomics, proteomics, metabolomics, advanced biostatistics, imaging, calorimetry, cell biology, challenge tests (meals, exercise, etc., and integration of all data by systems biology, will provide insight on a much higher level than today in a field we may name molecular nutrition research. To take advantage of all the new technologies scientists should develop international collaboration and gather data in large open access databases like the suggested Nutritional Phenotype database (dbNP. This collaboration will promote standardization of procedures (SOP, and provide a possibility to use collected data in future research projects. The ultimate goals of future nutritional research are to understand the detailed mechanisms of action for how nutrients/foods interact with the body and thereby enhance health and treat diet-related diseases.

Molecular Nutrition Research—The Modern Way Of Performing Nutritional Science

Science.gov (United States)

Norheim, Frode; Gjelstad, Ingrid M. F.; Hjorth, Marit; Vinknes, Kathrine J.; Langleite, Torgrim M.; Holen, Torgeir; Jensen, Jørgen; Dalen, Knut Tomas; Karlsen, Anette S.; Kielland, Anders; Rustan, Arild C.; Drevon, Christian A.

2012-01-01

In spite of amazing progress in food supply and nutritional science, and a striking increase in life expectancy of approximately 2.5 months per year in many countries during the previous 150 years, modern nutritional research has a great potential of still contributing to improved health for future generations, granted that the revolutions in molecular and systems technologies are applied to nutritional questions. Descriptive and mechanistic studies using state of the art epidemiology, food intake registration, genomics with single nucleotide polymorphisms (SNPs) and epigenomics, transcriptomics, proteomics, metabolomics, advanced biostatistics, imaging, calorimetry, cell biology, challenge tests (meals, exercise, etc.), and integration of all data by systems biology, will provide insight on a much higher level than today in a field we may name molecular nutrition research. To take advantage of all the new technologies scientists should develop international collaboration and gather data in large open access databases like the suggested Nutritional Phenotype database (dbNP). This collaboration will promote standardization of procedures (SOP), and provide a possibility to use collected data in future research projects. The ultimate goals of future nutritional research are to understand the detailed mechanisms of action for how nutrients/foods interact with the body and thereby enhance health and treat diet-related diseases. PMID:23208524

Molecular nutrition research: the modern way of performing nutritional science.

Science.gov (United States)

Norheim, Frode; Gjelstad, Ingrid Merethe Fange; Hjorth, Marit; Vinknes, Kathrine J; Langleite, Torgrim M; Holen, Torgeir; Jensen, Jørgen; Dalen, Knut Tomas; Karlsen, Anette S; Kielland, Anders; Rustan, Arild C; Drevon, Christian A

2012-12-03

In spite of amazing progress in food supply and nutritional science, and a striking increase in life expectancy of approximately 2.5 months per year in many countries during the previous 150 years, modern nutritional research has a great potential of still contributing to improved health for future generations, granted that the revolutions in molecular and systems technologies are applied to nutritional questions. Descriptive and mechanistic studies using state of the art epidemiology, food intake registration, genomics with single nucleotide polymorphisms (SNPs) and epigenomics, transcriptomics, proteomics, metabolomics, advanced biostatistics, imaging, calorimetry, cell biology, challenge tests (meals, exercise, etc.), and integration of all data by systems biology, will provide insight on a much higher level than today in a field we may name molecular nutrition research. To take advantage of all the new technologies scientists should develop international collaboration and gather data in large open access databases like the suggested Nutritional Phenotype database (dbNP). This collaboration will promote standardization of procedures (SOP), and provide a possibility to use collected data in future research projects. The ultimate goals of future nutritional research are to understand the detailed mechanisms of action for how nutrients/foods interact with the body and thereby enhance health and treat diet-related diseases.

Self-corrected sensors based on atomic absorption spectroscopy for atom flux measurements in molecular beam epitaxy

International Nuclear Information System (INIS)

Du, Y.; Liyu, A. V.; Droubay, T. C.; Chambers, S. A.; Li, G.

2014-01-01

A high sensitivity atom flux sensor based on atomic absorption spectroscopy has been designed and implemented to control electron beam evaporators and effusion cells in a molecular beam epitaxy system. Using a high-resolution spectrometer and a two-dimensional charge coupled device detector in a double-beam configuration, we employ either a non-resonant line or a resonant line with low cross section from the same hollow cathode lamp as the reference for nearly perfect background correction and baseline drift removal. This setup also significantly shortens the warm-up time needed compared to other sensor technologies and drastically reduces the noise coming from the surrounding environment. In addition, the high-resolution spectrometer allows the most sensitive resonant line to be isolated and used to provide excellent signal-to-noise ratio

Terroir of yeasts? – Application of FTIR spectroscopy and molecular methods for strain typing of yeasts

Directory of Open Access Journals (Sweden)

Gerhards Daniel

2015-01-01

Full Text Available The site specific influence on wine (Terroir is an often by wine producers, consumers and scientists discussed topic in the world of wine. A study on grapes and (spontaneous fermentations from six different vineyards was done to investigate the biodiversity of yeasts and to answer the question if there is a terroir of yeast and how it could be influenced. Randomly isolated yeasts were identified by FTIR-spectroscopy and molecular methods on species and strain level. Vineyard specific yeast floras would be observed but they are not such important as expected. Only a few overlapping strain patterns would be identified during both vintages. The yeast flora of the winery had a huge impact on the spontaneous fermentations, but is not really constant and influenced by different factors from outside.

Dielectric spectroscopy of the SmQ* phase

Science.gov (United States)

Perkowski, P.; Bubnov, A.; Piecek, W.; Ogrodnik, K.; Hamplová, V.; Kašpar, M.

2011-11-01

Liquid crystal possessing two biphenyl moieties in the molecular core and lateral chlorine substitution far from the chiral chain has been studied by dielectric spectroscopy. On cooling from the isotropic phase, the material possesses the frustrated smectic Q* (SmQ*) and SmCA* phases. It has been confirmed by dielectric spectroscopy that the SmQ* phase can be related to the SmCA* anti-ferroelectric phase. However, only one relaxation process has been observed in the SmQ* phase, while in the SmCA*, two relaxations are clearly detectable. It seems that the mode found in the SmQ* can be connected with high-frequency anti-phase mode observed in the SmCA* phase. Its relaxation frequency is similar to PH relaxation frequency, but is weaker. The same relaxation has been observed even a few degrees above the SmQ*-Iso phase transition. Another explanation for the mode detected in SmQ* and isotropic phases can be molecular motions around short molecular axis.

14th international symposium on molecular beams

International Nuclear Information System (INIS)

1992-01-01

This report discusses research being conducted with molecular beams. The general topic areas are as follows: Clusters I; reaction dynamics; atomic and molecular spectroscopy; clusters II; new techniques; photodissociation ampersand dynamics; and surfaces

In vivo spectroscopy

International Nuclear Information System (INIS)

Williams, S.R.; Cady, E.B.

1987-01-01

The technique which the authors describe in this chapter provides alternative information to imaging, although based upon the same physical principles. The experiments are carried out differently and have instrumental requirements which are not met by a standard imaging system. Furthermore, although the clinical efficacy of NMR imaging has been proven, clinical spectroscopy is very much in its infancy. With the exception of some specific /sup 31/P applications not is not even clear how spectroscopic investigations will be performed. This is particularly true with regard to localization techniques for investigating other than superficial organs and and in the use of /sup 1/H spectroscopy. They attempt to show what information spectroscopy can provide in principle and point out some of the problems associated with such investigations. NMR has come to the notice of the clinical community mainly through its use as an imaging technique, and many may consider spectroscopy as a secondary discipline. NMR spectroscopy, however, has a longer history than imaging and has been a standard technique in chemistry laboratories for more than two decades. It is a technique without peer for structural analysis of molecules and no new chemical compound is discovered or synthesized without an NMR spectrum being taken. The influence of molecular structure on resonant frequency has been termed the chemical shift

ISIS muons for materials and molecular science studies

International Nuclear Information System (INIS)

King, Philip J C; Cottrell, Stephen P; Hillier, Adrian D; Cox, Stephen F J; De Renzi, Roberto

2013-01-01

This paper marks the first 25 years of muon production at ISIS and the creation in that time of a facility dedicated to the use of these elementary particles as unique microscopic probes in condensed matter and molecular science. It introduces the basic techniques of muon spin rotation, relaxation and resonance, collectively known as μSR, that were already in use by specialist groups at other accelerator labs by the mid-1980s. It describes how these techniques have been implemented and made available at ISIS, beginning in 1987, and how they have evolved and improved since then. Ever widening applications embrace magnetism, superconductivity, interstitial diffusion and charge transport, semiconductors and dielectrics, chemical physics and radical chemistry. Over these first 25 years, a fully supported user facility has been established, open to all academic and industrial users. It presently comprises four scheduled instruments, optimized for different types of measurement, together with auxiliary equipment for radiofrequency or microwave spin manipulation and future plans for pump–probe laser excitation. (comment)

Lasers in atomic, molecular and nuclear physics

International Nuclear Information System (INIS)

Letokhov, V.S.

1986-01-01

This book presents papers on laser applications in atomic, molecular and nuclear physics. Specifically discussed are: laser isotope separation; laser spectroscopy of chlorophyll; laser spectroscopy of molecules and cell membranes; laser detection of atom-molecule collisions and lasers in astrophysics

Molecular pathological epidemiology of epigenetics: emerging integrative science to analyze environment, host, and disease.

Science.gov (United States)

Ogino, Shuji; Lochhead, Paul; Chan, Andrew T; Nishihara, Reiko; Cho, Eunyoung; Wolpin, Brian M; Meyerhardt, Jeffrey A; Meissner, Alexander; Schernhammer, Eva S; Fuchs, Charles S; Giovannucci, Edward

2013-04-01

Epigenetics acts as an interface between environmental/exogenous factors, cellular responses, and pathological processes. Aberrant epigenetic signatures are a hallmark of complex multifactorial diseases (including neoplasms and malignancies such as leukemias, lymphomas, sarcomas, and breast, lung, prostate, liver, and colorectal cancers). Epigenetic signatures (DNA methylation, mRNA and microRNA expression, etc) may serve as biomarkers for risk stratification, early detection, and disease classification, as well as targets for therapy and chemoprevention. In particular, DNA methylation assays are widely applied to formalin-fixed, paraffin-embedded archival tissue specimens as clinical pathology tests. To better understand the interplay between etiological factors, cellular molecular characteristics, and disease evolution, the field of 'molecular pathological epidemiology (MPE)' has emerged as an interdisciplinary integration of 'molecular pathology' and 'epidemiology'. In contrast to traditional epidemiological research including genome-wide association studies (GWAS), MPE is founded on the unique disease principle, that is, each disease process results from unique profiles of exposomes, epigenomes, transcriptomes, proteomes, metabolomes, microbiomes, and interactomes in relation to the macroenvironment and tissue microenvironment. MPE may represent a logical evolution of GWAS, termed 'GWAS-MPE approach'. Although epigenome-wide association study attracts increasing attention, currently, it has a fundamental problem in that each cell within one individual has a unique, time-varying epigenome. Having a similar conceptual framework to systems biology, the holistic MPE approach enables us to link potential etiological factors to specific molecular pathology, and gain novel pathogenic insights on causality. The widespread application of epigenome (eg, methylome) analyses will enhance our understanding of disease heterogeneity, epigenotypes (CpG island methylator

Near-infrared laboratory spectroscopy of mineral chemistry: A review

Science.gov (United States)

Meer, Freek van der

2018-03-01

Spectroscopy is the science concerned with the investigation and measurement of spectra produced when materials interacts with or emits electromagnetic radiation. Commercial infrared spectrometer were designed from the 1950's onward and found their way into the pharmaceutical and chemical industries. In the 1970's and 1980's also natural sciences notably mineralogy and vegetation science started systematically to measure optical properties of leaves and minerals/rocks with spectrometers. In the last decade spectroscopy has made the step from qualitative observations of mineral classes, soil type and vegetation biomass to quantitative estimates of mineral, soil and vegetation chemistry. This resulted in geothermometers used to characterize metamorphic and hydrothermal systems and to the advent of foliar biochemistry. More research is still needed to bridge the gap between laboratory spectroscopy and field spectroscopy. Empirical studies of minerals either as soil or rock constituents (and vegetation parameters) derived from regression analysis of spectra against chemistry is important in understanding the physics of the interaction of electromagnetic radiation and matter which in turn is important in the design of future satellite missions. Physics based models and retrievals are needed to operationalize these relationships and implement them in future earth observation missions as these are more robust and easy to transfer to other areas and data sets.

Parallelism between gradient temperature raman spectroscopy and differential scanning calorimetry results

Science.gov (United States)

Temperature dependent Raman spectroscopy (TDR) applies the temperature gradients utilized in differential scanning calorimetry (DSC) to Raman spectroscopy, providing a straightforward technique to identify molecular rearrangements that occur just prior to phase transitions. Herein we apply TDR and D...

Ultra-Broadband Two-Dimensional Electronic Spectroscopy and Pump-Probe Microscopy of Molecular Systems

Science.gov (United States)

Spokoyny, Boris M.

Ultrafast spectroscopy offers an unprecedented view on the dynamic nature of chemical reactions. From charge transfer in semiconductors to folding and isomerization of proteins, these all important processes can now be monitored and in some instances even controlled on real, physical timescales. One of the biggest challenges of ultrafast science is the incredible energetic complexity of most systems. It is not uncommon to encounter macromolecules or materials with absorption spectra spanning significant portions of the visible spectrum. Monitoring a multitude of electronic and vibrational transitions, all dynamically interacting with each other on femtosecond timescales poses a truly daunting experimental task. The first part of this thesis deals with the development of a novel Two-Dimensional Electronic Spectroscopy (2DES) and its associated, advanced detection methodologies. Owing to its ultra-broadband implementation, this technique enables us to monitor femtosecond chemical dynamics that span the energetic landscape of the entire visible spectrum. In order to demonstrate the utility of our method, we apply it to two laser dye molecules, IR-144 and Cresyl Violet. Variation of photophysical properties on a microscopic scale in either man-made or naturally occurring systems can have profound implications on how we understand their macroscopic properties. Recently, inorganic hybrid perovskites have been tapped as the next generation solar energy harvesting materials. Their remarkable properties include low exciton binding energy, low exciton recombination rates and long carrier diffusion lengths. Nevertheless, considerable variability in device properties made with nearly identical preparation methods has puzzled the community. In the second part of this thesis we use non-linear pump probe microscopy to study the heterogeneous nature of femtosecond carrier dynamics in thin film perovskites. We show that the local morphology of the perovskite thin films has a

Nuclear Magnetic Resonance Spectroscopy

Indian Academy of Sciences (India)

Home; Journals; Resonance – Journal of Science Education; Volume 9; Issue 1. Nuclear Magnetic Resonance Spectroscopy. Susanta Das. General Article Volume 9 Issue 1 January 2004 pp 34-49. Fulltext. Click here to view fulltext PDF. Permanent link: https://www.ias.ac.in/article/fulltext/reso/009/01/0034-0049. Keywords.

Cavity-enhanced spectroscopy and sensing

Energy Technology Data Exchange (ETDEWEB)

Gagliardi, Gianluca [CNR-Istituto Nazionale di Ottica (INO), Pozzuoli (Italy); Loock, Hans-Peter (ed.) [Queen' s Univ., Kingston, ON (Canada). Dept. of Chemistry

2014-07-01

The book reviews the dramatic recent advances in the use of optical resonators for high sensitivity and high resolution molecular spectroscopy as well as for chemical, mechanical and physical sensing. It encompasses a variety of cavities including those made of two or more mirrors, optical fiber loops, fiber gratings and spherical cavities. The book focuses on novel techniques and their applications. Each chapter is written by an expert and/or pioneer in the field. These experts also provide the theoretical background in optics and molecular physics where needed. Examples of recent breakthroughs include the use of frequency combs (Nobel prize 2005) for cavity enhanced sensing and spectroscopy, the use of novel cavity materials and geometries, the development of optical heterodyne detection techniques combined to active frequency-locking schemes. These methods allow the use and interrogation of optical resonators with a variety of coherent light sources for trace gas detection and sensing of strain, temperature and pressure.

Cavity-enhanced spectroscopy and sensing

CERN Document Server

Loock, Hans-Peter

2014-01-01

The book reviews the dramatic recent advances in the use of optical resonators for high sensitivity and high resolution molecular spectroscopy as well as for chemical, mechanical and physical sensing.  It encompasses a variety of cavities including those made of two or more mirrors, optical fiber loops, fiber gratings and spherical cavities. The book focuses on novel techniques and their applications. Each chapter is written by an expert and/or pioneer in the field. These experts also provide the theoretical background in optics and molecular physics where needed. Examples of recent breakthroughs include the use of frequency combs (Nobel prize 2005) for cavity enhanced sensing and spectroscopy, the use of novel cavity materials and geometries, the development of optical heterodyne detection techniques combined to active frequency-locking schemes. These methods allow the use and interrogation of optical resonators with a variety of coherent light sources for trace gas detection and sensing of strain, temperat...

Alteration of biomacromolecule in corn by steam flaking in relation to biodegradation kinetics in ruminant, revealed with vibrational molecular spectroscopy.

Science.gov (United States)

Xu, Ningning; Liu, Jianxin; Yu, Peiqiang

2018-02-15

Large scale of steam flaked corn has been used in dairy ration to maintain high milk production level. This study aimed to determine effects of steam flaking on processing-induced intrinsic molecular structure changes that were associated with rumen degradation kinetics and nutrients supply. The advanced vibrational molecular spectroscopy was applied to reveal the processing-induced intrinsic structure changes on a molecular basis. The rumen degradation kinetics and nutrient supply were determined using in situ approach in ruminant livestock system. Raw corn grain (RC) and steam flaked corn grain (SFC) were obtained from two different processing plants. The results showed that (1) Compared to RC, SFC had greater truly digestible non-fiber carbohydrate [tdNFC: 86.8 versus 78.0% dry matter (DM)], but lower truly digestible crude protein [tdCP: 7.7 versus 9.0% DM]. (2) The steam flaking increased (PMolecular absorbance intensities of most carbohydrate biopolymers were greater in SFC (Pmolecular spectral intensities were lower (Pmolecular structure and nutrient interactive study showed that carbohydrate spectral intensities were positively (Pmolecular structure changes had an interactive relationship with rumen degradation kinetics. Copyright © 2017 Elsevier B.V. All rights reserved.

Combining vibrational biomolecular spectroscopy with chemometric techniques for the study of response and sensitivity of molecular structures/functional groups mainly related to lipid biopolymer to various processing applications.

Science.gov (United States)

Yu, Gloria Qingyu; Yu, Peiqiang

2015-09-01

The objectives of this project were to (1) combine vibrational spectroscopy with chemometric multivariate techniques to determine the effect of processing applications on molecular structural changes of lipid biopolymer that mainly related to functional groups in green- and yellow-type Crop Development Centre (CDC) pea varieties [CDC strike (green-type) vs. CDC meadow (yellow-type)] that occurred during various processing applications; (2) relatively quantify the effect of processing applications on the antisymmetric CH3 ("CH3as") and CH2 ("CH2as") (ca. 2960 and 2923 cm(-1), respectively), symmetric CH3 ("CH3s") and CH2 ("CH2s") (ca. 2873 and 2954 cm(-1), respectively) functional groups and carbonyl C=O ester (ca. 1745 cm(-1)) spectral intensities as well as their ratios of antisymmetric CH3 to antisymmetric CH2 (ratio of CH3as to CH2as), ratios of symmetric CH3 to symmetric CH2 (ratio of CH3s to CH2s), and ratios of carbonyl C=O ester peak area to total CH peak area (ratio of C=O ester to CH); and (3) illustrate non-invasive techniques to detect the sensitivity of individual molecular functional group to the various processing applications in the recently developed different types of pea varieties. The hypothesis of this research was that processing applications modified the molecular structure profiles in the processed products as opposed to original unprocessed pea seeds. The results showed that the different processing methods had different impacts on lipid molecular functional groups. Different lipid functional groups had different sensitivity to various heat processing applications. These changes were detected by advanced molecular spectroscopy with chemometric techniques which may be highly related to lipid utilization and availability. The multivariate molecular spectral analyses, cluster analysis, and principal component analysis of original spectra (without spectral parameterization) are unable to fully distinguish the structural differences in the

Uncovering molecular relaxation processes with nonlinear spectroscopies in the deep UV

International Nuclear Information System (INIS)

West, Brantley A.; Molesky, Brian P.; Giokas, Paul G.; Moran, Andrew M.

2013-01-01

Highlights: • We discuss the outlook for multidimensional spectroscopies in the deep UV. • Photophysics are examined in small DNA components at cryogenic temperatures. • Wavepacket motions are detected in ring-opening systems with 2DUV spectroscopy. • Measurements of electronic wavepacket motions in molecules are proposed. - Abstract: Nonlinear laser spectroscopies in the deep UV spectral range are motivated by studies of biological systems and elementary processes in small molecules. This perspective article discusses recent technical advances in this area with a particular emphasis on diffractive optic based approaches to four-wave mixing spectroscopies. Applications to two classes of systems illustrate present experimental capabilities. First, experiments on DNA components at cryogenic temperatures are used to uncover features of excited state potential energy surfaces and vibrational cooling mechanisms. Second, sub-200 fs internal conversion processes and coherent wavepacket motions are investigated in cyclohexadiene and α-terpinene. Finally, we propose new experimental directions that combine methods for producing few-cycle UV laser pulses in noble gases with incoherent detection methods (e.g., photoionization) in experiments with time resolution near a singlefemtosecond. These measurements are motivated by knowledge of extremely fast non-adiabatic dynamics and the resolution of electronic wavepacket motions in molecules

Polymer Molecular Weight Analysis by [Superscript 1]H NMR Spectroscopy

Science.gov (United States)

Izunobi, Josephat U.; Higginbotham, Clement L.

2011-01-01

The measurement and analysis of molecular weight and molecular weight distribution remain matters of fundamental importance for the characterization and physical properties of polymers. Gel permeation chromatography (GPC) is the most routinely used method for the molecular weight determination of polymers whereas matrix-assisted laser…

Spectroscopy Division: progress report for 1990

International Nuclear Information System (INIS)

Sharma, A.; Marathe, S.M.

1991-01-01

This report summarises the work done by members of the Spectroscopy Division both within BARC as well as in scientific institutions elsewhere during the calendar year 1990. Main areas of research activity include atomic spectroscopy for hyperfine structure and isotope shift determination, theoretical and experimental studies of diatomic molecules, infrared and Raman spectroscopy of polyatomic molecules, design and fabrication of beam line optics for INDUS-I synchrotron radiation source, beam foil spectroscopy and laser spectroscopy of various atomic and molecular systems. Major experimental facilities that have been utilised include a fourier transform spectrometer, an excimer laser pumped dye-laser and a continous wave argon-ion laser. The report also includes the spectroscopic analytical service rendered for various DAE units and describes briefly some new analytical facilities like laser enhanced ionization in flames and resonance ionization mass spectroscopy using pulsed lasers which are being set up. The above activites were reported by members of the Spectroscopy Division via invited lectures, papers presented in various national and international conferences and publication in scientific journals. Details of these are given at the end of the report. (author). figs., tabs

An Overview of the Evolution of Infrared Spectroscopy Applied to Bacterial Typing.

Science.gov (United States)

Quintelas, Cristina; Ferreira, Eugénio C; Lopes, João A; Sousa, Clara

2018-01-01

The sustained emergence of new declared bacterial species makes typing a continuous challenge for microbiologists. Molecular biology techniques have a very significant role in the context of bacterial typing, but they are often very laborious, time consuming, and eventually fail when dealing with very closely related species. Spectroscopic-based techniques appear in some situations as a viable alternative to molecular methods with advantages in terms of analysis time and cost. Infrared and mass spectrometry are among the most exploited techniques in this context: particularly, infrared spectroscopy emerged as a very promising method with multiple reported successful applications. This article presents a systematic review on infrared spectroscopy applications for bacterial typing, highlighting fundamental aspects of infrared spectroscopy, a detailed literature review (covering different taxonomic levels and bacterial species), advantages, and limitations of the technique over molecular biology methods and a comparison with other competing spectroscopic techniques such as MALDI-TOF MS, Raman, and intrinsic fluorescence. Infrared spectroscopy possesses a high potential for bacterial typing at distinct taxonomic levels and worthy of further developments and systematization. The development of databases appears fundamental toward the establishment of infrared spectroscopy as a viable method for bacterial typing. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Journal of Chemical Sciences | Indian Academy of Sciences

Indian Academy of Sciences (India)

... Physics · Proceedings – Mathematical Sciences · Resonance – Journal of Science ... Home; Journals; Journal of Chemical Sciences; Special Issues ... 2nd International Symposium on Materials Chemistry (ISMC-2008) ... New Directions of Research in Molecules and Materials ... Theoretical Models for Molecular Structure.

EDITORIAL: Molecular Imaging Technology

Science.gov (United States)

Asai, Keisuke; Okamoto, Koji

2006-06-01

'Molecular Imaging Technology' focuses on image-based techniques using nanoscale molecules as sensor probes to measure spatial variations of various species (molecular oxygen, singlet oxygen, carbon dioxide, nitric monoxide, etc) and physical properties (pressure, temperature, skin friction, velocity, mechanical stress, etc). This special feature, starting on page 1237, contains selected papers from The International Workshop on Molecular Imaging for Interdisciplinary Research, sponsored by the Ministry of Education, Culture, Sports, Science and Technology (MEXT) in Japan, which was held at the Sendai Mediatheque, Sendai, Japan, on 8 9 November 2004. The workshop was held as a sequel to the MOSAIC International Workshop that was held in Tokyo in 2003, to summarize the outcome of the 'MOSAIC Project', a five-year interdisciplinary project supported by Techno-Infrastructure Program, the Special Coordination Fund for Promotion of Science Technology to develop molecular sensor technology for aero-thermodynamic research. The workshop focused on molecular imaging technology and its applications to interdisciplinary research areas. More than 110 people attended this workshop from various research fields such as aerospace engineering, automotive engineering, radiotechnology, fluid dynamics, bio-science/engineering and medical engineering. The purpose of this workshop is to stimulate intermixing of these interdisciplinary fields for further development of molecular sensor and imaging technology. It is our pleasure to publish the seven papers selected from our workshop as a special feature in Measurement and Science Technology. We will be happy if this issue inspires people to explore the future direction of molecular imaging technology for interdisciplinary research.

SU-E-T-44: A Micro-Raman Spectroscopy Study of the Dose-Dependence of EBT3 GafChromicTM Films for Quantifying the Degree of Molecular Polymerization

Energy Technology Data Exchange (ETDEWEB)

Callens, M; Van Den Abeele, K [Department of Physics, Wave Propagation and Signal Processing, KU Leuven KULAK, Kortrijk (Belgium); Crijns, W; Depuydt, T; Maes, F; Haustermans, K [Department of Radiation Oncology, KU Leuven, Leuven (Belgium); Simons, V [IMEC, Leuven (Belgium); De Wolf, I [IMEC, Leuven (Belgium); Department of Materials Engineering, KU Leuven, Leuven (Belgium); D’hooge, J [Department of Cardiovascular Sciences, Bio-Medical Science Group, KU Leuven, Leuven (Belgium); D’Agostino, E [DoseVue NV, Hasselt (Belgium); Pfeiffer, H [Department of Materials Engineering, KU Leuven, Leuven (Belgium)

2015-06-15

Purpose: Radiochromic films, such as the poly-diacetylene-based EBT3 GafChromic{sup TM} films (Ashland Specialty Ingredients, Wayne, NY, USA), are widely used for dosimetry applications because of their clear energy independence, high spatial resolution, near tissue equivalence and easy handling. The films undergo a slight color change by radiation-induced polymerization of diacetylene monomers. But more importantly, the film becomes optically less transparent with increasing radiation dose, with a saturation starting between 10 and 20 Gy, i.e. a common SBRT dose level. In contrast to the chromatic properties, less attention has been given to the underlying molecular mechanism that induces this partial color change and strongly reduces the transparency. Therefore, the current work investigates the variation of the molecular composition of the active layer of EBT3 films for an SBRT dose range. Method: Uncoated EBT3 films were irradiated with a 6 MV photon beam using dose levels between 0 and 20 Gy. The relative variation of the polymer content as a function of the applied radiation dose was studied using micro-Raman spectroscopy. Raman spectroscopy with a 633 nm probe laser incident on the active layer allowed to identify the film constituents and to estimate the amount of poly-diacetylenes from the intensities of the unique molecular vibrations of the molecule. Results: The normalized intensity of all polymeric vibrations, and most notably the polymeric triple and double carbon-carbon bonds at 2058 cm{sup −1} and 1446 cm{sup −1} respectively, increase with increasing dose up to a saturation level starting at about 10 Gy, indicating a corresponding increase and saturation of the amount of polymers. This molecular saturation process is the main cause of the non-linear dose response (i.e. a transparency reduction) and of the limited dose range of the studied films. Conclusion: Raman spectroscopy provides new and more fundamental insights in the mechanism of the

Theory for Nonlinear Spectroscopy of Vibrational Polaritons

OpenAIRE

Ribeiro, RF; Dunkelberger, AD; Xiang, B; Xiong, W; Simpkins, BS; Owrutsky, JC; Yuen-Zhou, J

2017-01-01

Molecular polaritons have gained considerable attention due to their potential to control nanoscale molecular processes by harnessing electromagnetic coherence. Although recent experiments with liquid-phase vibrational polaritons have shown great promise for exploiting these effects, significant challenges remain in interpreting their spectroscopic signatures. In this letter, we develop a quantum-mechanical theory of pump-probe spectroscopy for this class of polaritons based on the quantum La...

Annual reports on NMR spectroscopy

CERN Document Server

Webb, Graham A; McCarthy, M J

1995-01-01

Over recent years, no other technique has grown to such importance as that of NMR spectroscopy. It is used in all branches of science where precise structural determination is required and where the nature of interactions and reactions in solution is being studied. Annual Reports on NMR Spectroscopy has established itself as a means for the specialist and non-specialist alike to become familiar with new applications of the technique in all branches of chemistry, including biochemistry, and pharmaceutics. This volume focuses on theoretical aspects of NMR nuclear shielding and on applications of

Molecular speciation of phosphorus in organic amendments and amended soils using nuclear magnetic resonance and X-ray absorption spectroscopies

International Nuclear Information System (INIS)

Ajibove, B.

2007-01-01

Characterization of phosphorus (P) in organic amendments is essential for environmentally sustainable fertilization of agricultural soils. The sequential chemical extraction (SCE) technique commonly used for P characterization does not provide any direct molecular information about P species. Studies were conducted to characterize P species in organic amendments and amended soils at a molecular level. The SCE was used to fractionate P in organic amendments including biosolids, hog, dairy and beef cattle manures, and poultry litter. The extracts were analyzed for total P and P species using inductively coupled plasma - optical emission spectroscopy (ICP-OES) and solution 31 P nuclear magnetic resonance (NMR) spectroscopy, respectively. The relative proportions of P species in intact organic amendments and residues after each extraction, and calcareous soils amended with organic amendments and monoammonium phosphate (MAP) were estimated using the synchrotron-based P 1s X-ray absorption near edge structure (XANES) spectroscopy. The solution 31 P NMR provided a detailed characterization of organic P in the non-labile NaOH and HCl fractions of organic amendments, but was limited in characterizing the labile fractions of most of these organic amendments due to their proneness to alkaline hydrolysis. The XANES analysis, however, identified the actual chemical species constituting the labile P that was only characterized as inorganic P or orthophosphates by sequential extraction and solution 31 P NMR. In the amended Vertisolic and Chernozemic soils, XANES analysis estimated 'soluble and adsorbed P' as the dominant P species. For the Vertisolic soil, both the unamended and soil amended with biosolids and MAP contained hydroxyapatite (HAP). In addition, soil amended with biosolids, hog and dairy manures contained β-tricalcium phosphate (TRICAL), a more soluble CaP than HAP. TRICAL was found in all amended soils except in that amended with hog manure, while HAP was present

Resonance Ionization Mass Spectrometry (RIMS): applications in spectroscopy and chemical dynamics

International Nuclear Information System (INIS)

Naik, P.D.; Kumar, Awadhesh; Upadhyaya, Hari; Bajaj, P.N.

2009-01-01

Resonance ionization is a photophysical process wherein electromagnetic radiation is used to ionize atoms, molecules, transient species, etc., by exciting them through their quantum states. The number of photons required to ionize depends on the species being investigated and energy of the photon. Once a charged particle is produced, it is easy to detect it with high efficiency. With the advent of narrow band high power pulsed and cw tunable dye lasers, it has blossomed into a powerful spectroscopic and analytical technique, commonly known as resonance ionization spectroscopy (RIS)/resonance enhanced multiphoton ionization (REMPI). The alliance of resonance ionization with mass spectrometry has grown into a still more powerful technique, known as resonance ionization mass spectrometry (RIMS), which has made significant contributions in a variety of frontier areas of research and development, such as spectroscopy, chemical dynamics, analytical chemistry, cluster science, surface science, radiochemistry, nuclear physics, biology, environmental science, material science, etc. In this article, we shall describe the application of resonance ionization mass spectrometry to spectroscopy of uranium and chemical dynamics of polyatomic molecules

Journal of Chemical Sciences | Indian Academy of Sciences

Indian Academy of Sciences (India)

... XIONG1 WEIHUA ZHU1 HEMING XIAO1. Institute for Computation in Molecular and Materials Science and Department of Chemistry, School of Chemical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China; School of Materials Science and Engineering, Nanjing Institute of Technology, ...

Compact XFEL and AMO sciences: SACLA and SCSS

International Nuclear Information System (INIS)

Yabashi, M; Tanaka, H; Tanaka, T; Tomizawa, H; Nagasono, M; Ishikawa, T; Harries, J R; Hikosaka, Y; Hishikawa, A; Nagaya, K; Saito, N; Shigemasa, E; Yamanouchi, K; Ueda, K; Togashi, T

2013-01-01

The concept, design and performance of Japan's compact free-electron laser (FEL) facilities, the SPring-8 Compact SASE Source test accelerator (SCSS) and SPring-8 Angstrom Compact free electron LAser (SACLA), and their applications in mainly atomic, molecular and optical science are reviewed. At SCSS, intense, ultrafast FEL pulses at extreme ultraviolet (EUV) wavelengths have been utilized for investigating various multi-photon processes in atoms, molecules and clusters by means of ion and electron spectroscopy. The quantum optical effect superfluorescence has been observed with EUV excitation. A pump–probe technique combining FEL pulses with near infrared laser pulses has been realized to study the ultrafast dynamics of atoms, molecules and clusters in the sub-picosecond regime. At SACLA, deep inner-shell multi-photon ionization by intense x-ray FEL pulses has been investigated. The development of seeded FEL sources for producing transversely and temporally coherent light, as well as the expected impact on advanced science are discussed. (invited paper)

Spectroscopy Division: progress report for January 1989-December 1989

International Nuclear Information System (INIS)

Sharma, A.; Marathe, S.M.

1990-01-01

Research and development activities of the Spectroscopy Division during the calendar year 1989 are reported in the form of individual summaries which are grouped under the headings entitled: (i)analysis by optical emission spectroscopy, inductively coupled plasma atomic emission spectrometry and x-ray fluroescence techniques, (ii)atomic, molecular, solid state and laser-spectroscopy, (iii)optics and thin films, (iv)electronics, (v)fabrication, (vi)publications, and (vii)other academic activities. A divisional staff chart is given at the end. (author). figs., tabs

Rotational coherence spectroscopy at FLASH. Toward dynamic studies in nanosuperfluids

Energy Technology Data Exchange (ETDEWEB)

Kickermann, Andreas

2013-07-15

The field of molecular physics, which is focusing on molecular motion in the transition states of physical, chemical, and biological changes, is a wide-spread research area. It strives to reveal the structural and functional properties of molecules, the chemical bonds between atoms and the time evolution. Many processes occurring in nature upon electronic excitation proceed on the ultrafast femtosecond timescale and can be triggered by modern ultrashort femtosecond-laser sources under laboratory conditions. In the present thesis pump-probe studies were performed to follow molecular motion using ultrashort light pulses in the nanometer wavelength range provided by an XUV freeelectron laser (FEL). In detail, alignment of molecular species in space under field-free conditions was investigated. In the specific case of rotational wave packets in molecules the rotational dynamics shows characteristic temporal features, which contain a wealth of information on molecular structure and give insight into molecular coupling mechanisms, i.e. rotational constants and transition frequencies. Within this thesis, Rotational Coherence Spectroscopy (RCS) reveals wave-packet motion observed by subsequent Coulomb explosion of Raman excited carbon monoxide, which results in a time-dependent asymmetry of spatial fragmentation patterns. With the method presented here, the time resolution to elucidate the fast dynamics of strong couplings can be pushed toward a single rotational period even for the fastest rotors. This is due to large pump-probe delays with small subpicosecond step size. This kind of spectroscopy can also be expanded to molecular species, which are not accessible by other powerful spectroscopic methods, such as Fourier-transform microwave spectroscopy (FTMW). Furthermore, it allows to measure weak molecular couplings on a long timescale (large pump-probe delays), e.g. couplings of molecules in a solution or molecules dissolved in quantum fluids. This is valuable to

Rotational coherence spectroscopy at FLASH. Toward dynamic studies in nanosuperfluids

International Nuclear Information System (INIS)

Kickermann, Andreas

2013-07-01

The field of molecular physics, which is focusing on molecular motion in the transition states of physical, chemical, and biological changes, is a wide-spread research area. It strives to reveal the structural and functional properties of molecules, the chemical bonds between atoms and the time evolution. Many processes occurring in nature upon electronic excitation proceed on the ultrafast femtosecond timescale and can be triggered by modern ultrashort femtosecond-laser sources under laboratory conditions. In the present thesis pump-probe studies were performed to follow molecular motion using ultrashort light pulses in the nanometer wavelength range provided by an XUV freeelectron laser (FEL). In detail, alignment of molecular species in space under field-free conditions was investigated. In the specific case of rotational wave packets in molecules the rotational dynamics shows characteristic temporal features, which contain a wealth of information on molecular structure and give insight into molecular coupling mechanisms, i.e. rotational constants and transition frequencies. Within this thesis, Rotational Coherence Spectroscopy (RCS) reveals wave-packet motion observed by subsequent Coulomb explosion of Raman excited carbon monoxide, which results in a time-dependent asymmetry of spatial fragmentation patterns. With the method presented here, the time resolution to elucidate the fast dynamics of strong couplings can be pushed toward a single rotational period even for the fastest rotors. This is due to large pump-probe delays with small subpicosecond step size. This kind of spectroscopy can also be expanded to molecular species, which are not accessible by other powerful spectroscopic methods, such as Fourier-transform microwave spectroscopy (FTMW). Furthermore, it allows to measure weak molecular couplings on a long timescale (large pump-probe delays), e.g. couplings of molecules in a solution or molecules dissolved in quantum fluids. This is valuable to

UV-Vis spectroscopy of tyrosine side-groups in studies of protein structure. Part 2: selected applications.

Science.gov (United States)

Antosiewicz, Jan M; Shugar, David

2016-06-01

In Part 2 we discuss application of several different types of UV-Vis spectroscopy, such as normal, difference, and second-derivative UV absorption spectroscopy, fluorescence spectroscopy, linear and circular dichroism spectroscopy, and Raman spectroscopy, of the side-chain of tyrosine residues in different molecular environments. We review the ways these spectroscopies can be used to probe complex protein structures.

Effect of Molecular Guest Binding on the d-d Transitions of Ni2+ of CPO-27-Ni: A Combined UV-Vis, Resonant-Valence-to-Core X-ray Emission Spectroscopy, and Theoretical Study.

Science.gov (United States)

Gallo, Erik; Gorelov, Evgeny; Guda, Alexander A; Bugaev, Aram L; Bonino, Francesca; Borfecchia, Elisa; Ricchiardi, Gabriele; Gianolio, Diego; Chavan, Sachin; Lamberti, Carlo

2017-12-04

We used Ni K-edge resonant-valence-to-core X-ray emission spectroscopy (RVtC-XES, also referred to as direct RIXS), an element-selective bulk-sensitive synchrotron-based technique, to investigate the electronic structure of the CPO-27-Ni metal-organic framework (MOF) upon molecular adsorption of significant molecular probes: H 2 O, CO, H 2 S, and NO. We compare RVtC-XES with UV-vis spectroscopy, and we show that the element selectivity of RVtC-XES is of strategic significance to observe the full set of d-d excitations in Ni 2+ , which are partially overshadowed by the low-energy π-π* transitions of the Ni ligands in standard diffuse-reflectance UV-vis experiments. Our combined RVtC-XES/UV-vis approach provides access to the whole set of d-d excitations, allowing us a complete discussion of the changes undergone by the electronic configuration of the Ni 2+ sites hosted within the MOF upon molecular adsorption. The experimental data have been interpreted by multiplet ligand-field theory calculations based on Wannier orbitals. This study represents a step further in understanding the ability of the CPO-27-Ni MOFs in molecular sorption and separation applications.

Spatio-temporal image correlation spectroscopy and super-resolution microscopy to quantify molecular dynamics in T cells.

Science.gov (United States)

Ashdown, George W; Owen, Dylan M

2018-02-02

Many cellular processes are regulated by the spatio-temporal organisation of signalling complexes, cytoskeletal components and membranes. One such example is at the T cell immunological synapse where the retrograde flow of cortical filamentous (F)-actin from the synapse periphery drives signalling protein microclusters towards the synapse centre. The density of this mesh however, makes visualisation and analysis of individual actin fibres difficult due to the resolution limit of conventional microscopy. Recently, super-resolution methods such as structured illumination microscopy (SIM) have surpassed this resolution limit. Here, we apply SIM to better visualise the dense cortical actin meshwork in T cell synapses formed against activating, antibody-coated surfaces and image under total-internal reflection fluorescence (TIRF) illumination. To analyse the observed molecular flows, and the relationship between them, we apply spatio-temporal image correlation spectroscopy (STICS) and its cross-correlation variant (STICCS). We show that the dynamic cortical actin mesh can be visualised with unprecedented detail and that STICS/STICCS can output accurate, quantitative maps of molecular flow velocity and directionality from such data. We find that the actin flow can be disrupted using small molecule inhibitors of actin polymerisation. This combination of imaging and quantitative analysis may provide an important new tool for researchers to investigate the molecular dynamics at cellular length scales. Here we demonstrate the retrograde flow of F-actin which may be important for the clustering and dynamics of key signalling proteins within the plasma membrane, a phenomenon which is vital to correct T cell activation and therefore the mounting of an effective immune response. Copyright © 2018. Published by Elsevier Inc.

Journal of Chemical Sciences | Indian Academy of Sciences

Indian Academy of Sciences (India)

Author Affiliations. Santanu Bhattacharya1 Raghavan Varadarajan2. Department of Organic Chemistry, Indian Institute of Science, Bangalore 560 012; Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012 ...

Opportunities and limitations related to the application of plant-derived lipid molecular proxies in soil science

Directory of Open Access Journals (Sweden)

B. Jansen

2017-11-01

Full Text Available The application of lipids in soils as molecular proxies, also often referred to as biomarkers, has dramatically increased in the last decades. Applications range from inferring changes in past vegetation composition, climate, and/or human presence to unraveling the input and turnover of soil organic matter (SOM. The molecules used are extractable and non-extractable lipids, including ester-bound lipids. In addition, the carbon or hydrogen isotopic composition of such molecules is used. While holding great promise, the application of soil lipids as molecular proxies comes with several constraining factors, the most important of which are (i variability in the molecular composition of plant-derived organic matter both internally and between individual plants, (ii variability in (the relative contribution of input pathways into the soil, and (iii the transformation and/or (selective degradation of (some of the molecules once present in the soil. Unfortunately, the information about such constraining factors and their impact on the applicability of molecular proxies is fragmented and scattered. The purpose of this study is to provide a critical review of the current state of knowledge with respect to the applicability of molecular proxies in soil science, specifically focusing on the factors constraining such applicability. Variability in genetic, ontogenetic, and environmental factors influences plant n-alkane patterns in such a way that no unique compounds or specific molecular proxies pointing to, for example, plant community differences or environmental influences, exist. Other components, such as n-alcohols, n-fatty acids, and cutin- and suberin-derived monomers, have received far less attention in this respect. Furthermore, there is a high diversity of input pathways offering both opportunities and limitations for the use of molecular proxies at the same time. New modeling approaches might offer a possibility to unravel such mixed input

Molecular scale

Directory of Open Access Journals (Sweden)

Christopher H. Childers

2016-03-01

Full Text Available This manuscript demonstrates the molecular scale cure rate dependence of di-functional epoxide based thermoset polymers cured with amines. A series of cure heating ramp rates were used to determine the influence of ramp rate on the glass transition temperature (Tg and sub-Tg transitions and the average free volume hole size in these systems. The networks were comprised of 3,3′-diaminodiphenyl sulfone (33DDS and diglycidyl ether of bisphenol F (DGEBF and were cured at ramp rates ranging from 0.5 to 20 °C/min. Differential scanning calorimetry (DSC and NIR spectroscopy were used to explore the cure ramp rate dependence of the polymer network growth, whereas broadband dielectric spectroscopy (BDS and free volume hole size measurements were used to interrogate networks’ molecular level structural variations upon curing at variable heating ramp rates. It was found that although the Tg of the polymer matrices was similar, the NIR and DSC measurements revealed a strong correlation for how these networks grow in relation to the cure heating ramp rate. The free volume analysis and BDS results for the cured samples suggest differences in the molecular architecture of the matrix polymers due to cure heating rate dependence.

The characterisation of molecular boric acid by mass spectrometry and matrix isolation-infrared spectroscopy

International Nuclear Information System (INIS)

Ogden, J.S.; Young, N.A.; Bowsher, B.R.

1987-10-01

Boric acid (H 3 BO 3 ) is used as a soluble neutron absorber in the coolant of pressurised water reactors and will be an important species in defining the fission product chemistry of severe reactor accidents. Mass spectrometry and matrix isolation-infrared spectroscopy have been used to characterise boric acid in the vapour phase and hence assess the implications of any chemical interactions. Crystalline orthoboric acid vaporises to yield molecular H 3 BO 3 when heated in vacuum to approximately 40 0 C. The infrared spectrum of the vapour species isolated in low-temperature nitrogen matrices shows characteristic absorptions at 3668.5 (E'), 1426.2 (E'), 1009.9 (E'), 675.0 (A''), 513.8 (A'') and 448.9 (E') cm -1 , consistent with C 3h symmetry. These spectral assignments are supported by extensive isotope labelling, and by a partial normal co-ordinate analysis. These data will be used to quantify specific thermodynamic functions and hence assist in determining the magnitude of reactions such as boric acid with caesium iodide. (author)

Trace species detection: Spectroscopy and molecular energy transfer at high temperature

Energy Technology Data Exchange (ETDEWEB)

Gray, J.A. [Sandia National Laboratories, Livermore, CA (United States)

1993-12-01

Monitoring the concentration of trace species such as atomic and molecular free radicals is essential in forming predictive models of combustion processes. LIF-based techniques have the necessary sensitivity for concentration and temperature measurements but have limited accuracy due to collisional quenching in combustion applications. The goal of this program is to use spectroscopic and kinetic measurements to quantify nonradiative and collisional effects on LIF signals and to develop new background-free alternatives to LIF. The authors have measured the natural linewidth of several OH A-X (3,0) rotational transitions to determine predissociation lifetimes in the upper state, which were presumed to be short compared to quenching lifetimes, and as a result, quantitative predictions about the applicability of predissociation fluorescence methods at high pressures are made. The authors are investigating collisional energy transfer in the A-state of NO. Quenching rates which enable direct corrections to NO LIF quantum yields at high temperature were calculations. These quenching rates are now being used in studies of turbulence/chemistry interactions. The authors have measured the electric dipole moment {mu} of excited-state NO using Stark quantum-beat spectroscopy. {mu} is an essential input to a harpoon model which predicts quenching efficiencies for NO (A) by a variety of combustion-related species. The authors are developing new coherent multiphoton techniques for measurements of atomic hydrogen concentration in laboratory flames to avoid the quenching problems associated with previous multiphoton LIF schemes.

Molecular Modeling

Indian Academy of Sciences (India)

Home; Journals; Resonance – Journal of Science Education; Volume 9; Issue 5. Molecular Modeling: A Powerful Tool for Drug Design and Molecular Docking. Rama Rao Nadendla. General Article Volume 9 Issue 5 May 2004 pp 51-60. Fulltext. Click here to view fulltext PDF. Permanent link:

Gradient temperature Raman spectroscopy identifies flexible sites in proline and alanine peptides

Science.gov (United States)

Continuous thermo dynamic Raman spectroscopy (TDRS) applies the temperature gradients utilized in differential scanning calorimetry (DSC) to Raman spectroscopy, providing a straightforward technique to identify molecular rearrangements that occur just prior to phase transitions. Herein we apply TDRS...

Functionalization of gold and nanocrystalline diamond atomic force microscope tips for single molecule force spectroscopy

Science.gov (United States)

Drew, Michael E.

The atomic force microscope (AFM) has fueled interest in nanotechnology because of its ability to image surfaces at the nanometer level and act as a molecular force sensor. Functionalization of the surface of an AFM tip surface in a stable, controlled manner expands the capabilities of the AFM and enables additional applications in the fields of single molecule force spectroscopy and nanolithography. Two AFM tip functionalizations are described: the assembly of tripodal molecular tips onto gold AFM tips and the photochemical attachment of terminal alkenes to nanocrystalline diamond (NCD) AFM tips. Two separate tripodal molecules with different linker lengths and a monopodal molecule terminated with biotin were synthesized to attach to a gold AFM tip for single molecule force spectroscopy. The immobilization of these molecules was examined by contact angle measurements, spectroscopic ellipsometry, infrared, and near edge x-ray absorption fine structure (NEXAFS) spectroscopy. All three molecules displayed rupture forces that agreed with previously reported values for the biotin--avidin rupture. The tripodal molecular tip displayed narrower distribution in their force histograms than the monopodal molecular tip. The performance of the tripodal molecular tip was compared to the monopodal molecular tip in single molecule force spectroscopy studies. Over repeated measurements, the distribution of forces for the monopodal molecular tip shifted to lower forces, whereas the distribution for the tripodal molecular tip remained constant throughout. Loading rate dependence and control experiments further indicated that the rupture forces of the tripod molecular tips were specific to the biotin--NeutrAvidin interaction. The second functionalization method used the photochemical attachment of undecylenic acid to NCD AFM tips. The photochemical attachment of undecylenic acid to hydrogen-terminated NCD wafer surfaces was investigated by contact angle measurements, x

NMR and molecular modeling of wine tannins binding to saliva proteins: revisiting astringency from molecular and colloidal prospects.

Science.gov (United States)

Cala, Olivier; Pinaud, Noël; Simon, Cécile; Fouquet, Eric; Laguerre, Michel; Dufourc, Erick J; Pianet, Isabelle

2010-11-01

In organoleptic science, the association of tannins to saliva proteins leads to the poorly understood phenomenon of astringency. To decipher this interaction at molecular and colloidal levels, the binding of 4 procyanidin dimers (B1-4) and 1 trimer (C2) to a human saliva proline-rich peptide, IB7(14), was studied. Interactions have been characterized by measuring dissociation constants, sizes of complexes, number, and nature of binding sites using NMR (chemical shift variations, diffusion-ordered spectroscopy, and saturation transfer diffusion). The binding sites were identified using molecular mechanics, and the hydrophilic/hydrophobic nature of the interactions was resolved by calculating the molecular lipophilicity potential within the complexes. The following comprehensive scheme can be proposed: 1) below the tannin critical micelle concentration (CMC), interaction is specific, and the procyanidin anchorage always occurs on the same three IB7(14) sites. The tannin 3-dimensional structure plays a key role in the binding force and in the tannin's ability to act as a bidentate ligand: tannins adopting an extended conformation exhibit higher affinity toward protein and initiate the formation of a network. 2) Above the CMC, after the first specific hydrophilic interaction has taken place, a random hydrophobic stacking occurs between tannins and proteins. The whole process is discussed in the general frame of wine tannins eliciting astringency.

Vibrational Spectroscopy of Chromatographic Interfaces

Energy Technology Data Exchange (ETDEWEB)

Jeanne E. Pemberton

2011-03-10

Chromatographic separations play a central role in DOE-supported fundamental research related to energy, biological systems, the environment, and nuclear science. The overall portfolio of research activities in the Separations and Analysis Program within the DOE Office of Basic Energy Sciences includes support for activities designed to develop a molecular-level understanding of the chemical processes that underlie separations for both large-scale and analytical-scale purposes. The research effort funded by this grant award was a continuation of DOE-supported research to develop vibrational spectroscopic methods to characterize the interfacial details of separations processes at a molecular level.

Atomic and Molecular Data for Optical Stellar Spectroscopy

OpenAIRE

Heiter, U.; Lind, K.; Asplund, M.; Barklem, P. S.; Bergemann, M.; Magrini, L.; Masseron, T.; Mikolaitis, Š.; Pickering, J. C.; Ruffoni, M. P.

2015-01-01

High-precision spectroscopy of large stellar samples plays a crucial role for several topical issues in astrophysics. Examples include studying the chemical structure and evolution of the Milky Way galaxy, tracing the origin of chemical elements, and characterizing planetary host stars. Data are accumulating from instruments that obtain high-quality spectra of stars in the ultraviolet, optical and infrared wavelength regions on a routine basis. These instruments are located at ground-based 2-...

Fellowship | Indian Academy of Sciences

Indian Academy of Sciences (India)

Date of birth: 26 June 1951. Specialization: Raman Spectroscopy, Time-resolved Ultrafast Spectroscopy, Nanosystems such as Graphene, Nanotubes, Physics of Soft Condensed Matter Address: Professor, Department of Physics, Indian Institute of Science, Bengaluru 560 012, Karnataka Contact: Office: (080) 2360 2238, ...

Nuclear magnetic resonance spectroscopy in organic chemistry. 2. ed.

International Nuclear Information System (INIS)

Zschunke, A.

1977-01-01

The fundamentals of nuclear magnetic resonance spectroscopy are discussed only briefly. The emphasis is laid on developing reader's ability to evaluate resonance spectra. The following topics are covered: principles of nuclear magnetic resonance spectroscopy; chemical shift and indirect nuclear spin coupling constants and their relation to the molecular structure; analysis of spectra; and uses for structural analysis and solution of kinetic problems, mainly with regard to organic compounds. Of interest to chemists and graduate students who want to make themselves acquainted with nuclear magnetic resonance spectroscopy

Journal of Chemical Sciences | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Chemical Sciences; Volume 113; Issue 3 .... Excess molar volumes and viscosities of binary mixtures of 1,2-diethoxyethane with chloroalkanes ... IR-UV double resonance spectroscopy in jet and ab initio calculation.

Digitotalar dysmorphism: Molecular elucidation

African Journals Online (AJOL)

obtained for molecular studies. Since the distal arthrogryposes (DAs) are genetically heterogeneous, an unbiased approach to mutation ... Diseases and Molecular Medicine, Department of Pathology, Faculty of Health Sciences, University of Cape Town, South Africa, with an interest in molecular genetics of connective ...

Evidence for the molecular-scale origin of the suppression of physical ageing in confined polymer: fluorescence and dielectric spectroscopy studies of polymer-silica nanocomposites

International Nuclear Information System (INIS)

Priestley, Rodney D; Rittigstein, Perla; Broadbelt, Linda J; Fukao, Koji; Torkelson, John M

2007-01-01

Fluorescence spectroscopy was used to characterize the rate of physical ageing at room temperature in nanocomposites of silica (10-15 nm diameter) nanoparticles in poly(methyl methacrylate) (PMMA). The physical ageing rate was reduced by more than a factor of 20 in 0.4 vol% silica-PMMA nanocomposites relative to neat PMMA. The molecular-scale origin of this nearly complete arresting of physical ageing was investigated with dielectric spectroscopy. The strength of the β relaxation process was reduced by nearly 50% in the nanocomposite relative to neat PMMA. This reduced strength of the β process results from dipoles (ester groups) having hindered motions or being virtually immobile on the timescale being probed at a frequency of 100 Hz. This hindered mobility results from hydrogen bonding between PMMA ester side groups and hydroxyl units on the surface of the silica nanoparticles. In contrast, no reduction in physical ageing rate was observed upon addition of silica to polystyrene, which cannot form hydrogen bonds with the silica surfaces. Thus, the molecular origin of the suppressed physical ageing in silica-PMMA nanocomposites is the interfacial hydrogen bonding, which leads to a major reduction in the strength of the β process, i.e., the β process is largely responsible for the observed physical ageing

Vibrational Micro-Spectroscopy of Human Tissues Analysis: Review.

Science.gov (United States)

Bunaciu, Andrei A; Hoang, Vu Dang; Aboul-Enein, Hassan Y

2017-05-04

Vibrational spectroscopy (Infrared (IR) and Raman) and, in particular, micro-spectroscopy and micro-spectroscopic imaging have been used to characterize developmental changes in tissues, to monitor these changes in cell cultures and to detect disease and drug-induced modifications. The conventional methods for biochemical and histophatological tissue characterization necessitate complex and "time-consuming" sample manipulations and the results are rarely quantifiable. The spectroscopy of molecular vibrations using mid-IR or Raman techniques has been applied to samples of human tissue. This article reviews the application of these vibrational spectroscopic techniques for analysis of biological tissue published between 2005 and 2015.

Demystifying computer science for molecular ecologists.

Science.gov (United States)

Belcaid, Mahdi; Toonen, Robert J

2015-06-01

In this age of data-driven science and high-throughput biology, computational thinking is becoming an increasingly important skill for tackling both new and long-standing biological questions. However, despite its obvious importance and conspicuous integration into many areas of biology, computer science is still viewed as an obscure field that has, thus far, permeated into only a few of the biology curricula across the nation. A national survey has shown that lack of computational literacy in environmental sciences is the norm rather than the exception [Valle & Berdanier (2012) Bulletin of the Ecological Society of America, 93, 373-389]. In this article, we seek to introduce a few important concepts in computer science with the aim of providing a context-specific introduction aimed at research biologists. Our goal was to help biologists understand some of the most important mainstream computational concepts to better appreciate bioinformatics methods and trade-offs that are not obvious to the uninitiated. © 2015 John Wiley & Sons Ltd.

2012 Gordon Research Conference On Molecular And Ionic Clusters

International Nuclear Information System (INIS)

McCoy, Anne

2012-01-01

The Gordon Research Conference on 'Molecular and Ionic Clusters' focuses on clusters, which are the initial molecular species found in gases when condensation begins to occur. Condensation can take place solely from molecules interacting with each other, mostly at low temperatures, or when molecules condense around charged particles (electrons, protons, metal cations, molecular ions), producing ion molecule clusters. These clusters provide models for solvation, allow a pristine look at geometric as well as electronic structures of molecular complexes or matter in general, their interaction with radiation, their reactivity, their thermodynamic properties and, in particular, the related dynamics. This conference focuses on new ways to make clusters composed of different kinds of molecules, new experimental techniques to investigate the properties of the clusters and new theoretical methods with which to calculate the structures, dynamical motions and energetics of the clusters. Some of the main experimental methods employed include molecular beams, mass spectrometry, laser spectroscopy (from infrared to XUV; in the frequency as well as the time domain) and photoelectron spectroscopy. Techniques include laser absorption spectroscopy, laser induced fluorescence, resonance enhanced photoionization, mass-selected photodissociation, photofragment imaging, ZEKE photoelectron spectroscopy, etc. From the theoretical side, this conference highlights work on potential surfaces and measurable properties of the clusters. The close ties between experiment, theory and computation have been a hallmark of the Gordon Research Conference on Molecular and Ionic Clusters. In the 2012 meeting, we plan to have sessions that will focus on topics including: (1) The use of cluster studies to probe fundamental phenomena; (2) Finite size effects on structure and thermodynamics; (3) Intermolecular forces and cooperative effects; (4) Molecular clusters as models for solvation; and (5) Studies of

Investigation of Diode Pumped Alkali Laser Atmospheric Transmission Using Tunable Diode Laser Absorption Spectroscopy

Science.gov (United States)

2012-09-01

Optics Letters, 28(23):2336–2338, 2003. 48. Lavan, M. “High Energy Laser Systems for Short Range Defense”. Acta Physica Polonica -Series A General Physics...able diode laser spectrometer for the remote sensing of vehicle emissions”. Spec- trochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 60...P. “A review of recent advances in semiconductor laser based gas mon- itors”. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 54

Spectroscopy and astronomy: H3+ from the laboratory to the Galactic center.

Science.gov (United States)

Oka, Takeshi

2011-01-01

Since the serendipitous discovery of the Fraunhofer spectrum in the Sun in 1814 which initiated spectroscopy and astrophysics, spectroscopy developed hand in hand with astronomy. I discuss my own work on the infrared spectrum of H3+ from its discovery in the laboratory in 1980, in interstellar space in 1996, to recent studies in the Galactic center as an example of astronomical spectroscopy. Its spin-off, the spectroscopy of simple molecular ions, is also briefly discussed.

Spin dynamics study of magnetic molecular clusters by means of Moessbauer spectroscopy

International Nuclear Information System (INIS)

Cianchi, L.; Del Giallo, F.; Spina, G.; Reiff, W.; Caneschi, A.

2002-01-01

Spin dynamics of the two magnetic molecular clusters Fe4 and Fe8, with four and eight Fe(III) ions, respectively, was studied by means of Moessbauer spectroscopy. The transition probabilities W's between the spin states of the ground multiplet were obtained from the fitting of the spectra. For the Fe4 cluster we found that, in the range from 1.38 to 77 K, the trend of W's versus the temperature corresponds to an Orbach's process involving an excited state with energy of about 160 K. For the Fe8, which, due to the presence of a low-energy excited state, could not be studied at temperatures greater than 20 K, the trend of W's in the range from 4 to 18 K seems to correspond to a direct process. The correlation functions of the magnetization were then calculated in terms of the W's. They have an exponential trend for the Fe4 cluster, while a small oscillating component is also present for the Fe8 cluster. For the first of the clusters, τ vs T (τ is the decay time of the magnetization) has a trend which, at low temperatures (T 15 K, τ follows the trend of W -1 . For the Fe8, τ follows an Arrhenius law, but with a prefactor which is smaller than the one obtained susceptibility measurements

Design of Molecular Solar Cells via Feedback from Soft X-ray Spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Himpsel, Franz J. [Univ. of Wisconsin, Madison, WI (United States)

2015-06-12

Spectroscopy with soft X-rays was used to develop new materials and novel designs for solar cells and artificial photosynthesis. In order to go beyond the widely-used trial-and-error approach of gradually improving a particular design, we started from the most general layout of a solar cell (or a photo-electrochemical device) and asked which classes of materials are promising for best performance. For example, the most general design of a solar cell consists of a light absorber, an electron donor, and an electron acceptor. These are characterized by four energy levels, which were measured by a combination of spectroscopic X-ray techniques. Tuning synchrotron radiation to the absorption edges of specific elements provided element- and bond-selectivity. The spectroscopic results were complemented by state-of-the-art calculations of the electronic states. These helped explaining the observed energy levels and the orbitals associated with them. The calculations were extended to a large class of materials (for example thousands of porphyrin dye complexes) in order to survey trends in the energy level structure. A few highlights serve as examples: 1) Organic molecules combining absorber, donor, and acceptor with atomic precision. 2) Exploration of highly p-doped diamond films as inert, transparent electron donors. 3) Surface-sensitive characterization of nanorod arrays used as photoanodes in water splitting. 4) Computational design of molecular complexes for efficient solar cells using two photons.

Crossed molecular beams

International Nuclear Information System (INIS)

Lee, Y.T.

1976-01-01

Research activities with crossed molecular beams at Lawrence Berkeley Laboratory during 1976 are described. Topics covered include: scattering of Ar*, Kr*, with Xe; metastable rare gas interactions, He* + H 2 ; an atomic and molecular halogen beam source; a crossed molecular beam study of the Cl + Br 2 → BrCl + Br reaction; O( 3 P) reaction dynamics, development of the high pressure plasma beam source; energy randomization in the Cl + C 2 H 3 Br → Br + C 2 H 3 Cl reaction; high resolution photoionization studies of NO and ICl; photoionization of (H 2 O)/sub n/ and (NH 3 ) 2 ; photoionization mass spectroscopy of NH 3 + and O 3 + ; photo fragmentation of bromine; and construction of chemiluminescence-laser fluorescence crossed molecular beam machine

Energy transformation in molecular electronic systems. Progress report, December 1, 1981-November 30, 1982

International Nuclear Information System (INIS)

Kasha, M.

1982-01-01

Summaries are presented of studies on: molecular translational-rotovibronic Hamiltonians for nonlinear and linear molecules, singlet oxygen in potassium superoxide-water, proton-transfer spectroscopy of water in chromones, mechanism of 4-level molecular lasers, and cationic/anionic potential in proton-transfer spectroscopy

High-resolution inverse Raman and resonant-wave-mixing spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Rahn, L.A. [Sandia National Laboratories, Livermore, CA (United States)

1993-12-01

These research activities consist of high-resolution inverse Raman spectroscopy (IRS) and resonant wave-mixing spectroscopy to support the development of nonlinear-optical techniques for temperature and concentration measurements in combustion research. Objectives of this work include development of spectral models of important molecular species needed to perform coherent anti-Stokes Raman spectroscopy (CARS) measurements and the investigation of new nonlinear-optical processes as potential diagnostic techniques. Some of the techniques being investigated include frequency-degenerate and nearly frequency-degenerate resonant four-wave-mixing (DFWM and NDFWM), and resonant multi-wave mixing (RMWM).

Raman Spectroscopy of Microbial Pigments

Science.gov (United States)

Edwards, Howell G. M.; Oren, Aharon

2014-01-01

Raman spectroscopy is a rapid nondestructive technique providing spectroscopic and structural information on both organic and inorganic molecular compounds. Extensive applications for the method in the characterization of pigments have been found. Due to the high sensitivity of Raman spectroscopy for the detection of chlorophylls, carotenoids, scytonemin, and a range of other pigments found in the microbial world, it is an excellent technique to monitor the presence of such pigments, both in pure cultures and in environmental samples. Miniaturized portable handheld instruments are available; these instruments can be used to detect pigments in microbiological samples of different types and origins under field conditions. PMID:24682303

Laser Spectroscopy : XII International Conference

CERN Document Server

Allegrini, Maria; Sasso, Antonio

1996-01-01

This text includes all the recent advances in the field of laser spectroscopy. Major results span from the control of matter by electromagnetic fields (trapping and coding) to high precision measurements on simple atomic systems and to quantum optics with single atoms. It includes a report of the Bose-Einstein condensation achieved by laser-cooling of rubidium atoms. Achievements in the technology of tunable sources, in particular of miniaturized solid state devices, are also reported. Most recent advances in molecular spectroscopy are illustrated with emphasis on "cooled" spectra, clusters and high accuracy frequency references. Topics such as atomic interferometry and microcavity quantum optics are also covered.

Novel applications of photoacoustic spectroscopy in life sciences

Science.gov (United States)

Stolik, S.

2004-10-01

The Photoacoustic Spectroscopy, based on the generation of acoustic waves following the absorption of the modulated light by an enclosed material, was discovered in 1880 by Alexander Graham Bell. There are a lot of remarkable achievements in this topic since those days. It has been intended to present a relatively new tool to the researchers in biological areas and, simultaneously, to propose new fields of investigation to those who have been attracted by physics. The application of Photoacoustic trace gas detection to the determination of ethylene content in mice exhalation is described as a biomarker of free radicals production. It has been demonstrated the feasibility of studying the lipid peroxidation in vivo by this technique. Specifically, the results of δ-aminolevulinic acid administration in mice are presented. This drug has been used to induce Protoporphyrin IX production and ultimately to apply the Photodynamic Therapy, a recent method in cancer treatment. A kinetic study of Protoporphyrin IX production in mice skin and blood after δ-aminolevulinic acid administration in different doses is also shown. This study was performed using Photoacoustic Spectroscopy in solids.

Synchrotron radiation resonance Raman spectroscopy (SR3S)

International Nuclear Information System (INIS)

Hester, R.E.

1979-01-01

The use of normal Raman spectroscopy and resonance Raman spectroscopy to study the structure of molecular species and the nature of their chemical bonds is discussed. The availability of a fully tunable radiation source (the Synchrotron Radiation Source) extending into the ultraviolet raises the possibility of using synchrotron radiation resonance Raman spectroscopy as a sensitive and specific analytical probe. The pulsed nature of the SRS beam may be exploited for time-resolved resonance Raman spectroscopy and its high degree of polarization could be very helpful in the interpretation of spectra. The possibilities are considered under the headings: intensity requirements and comparison with other sources; some applications (e.g. structure of proteins; study of iron-porphyrin unit; study of chlorophylls). (U.K.)

Molecular Formula and Molecular Weight - NBDC NikkajiRDF | LSDB Archive [Life Science Database Archive metadata

Lifescience Database Archive (English)

Full Text Available List Contact us NBDC NikkajiRDF Molecular Formula and Molecular Weight Data detail Data name Molecular Formula and Molecul...- Description of data contents This RDF data includes molecular formula and molecular weight of chemical sub...ikkajiRDF_MFMW.tar.gz File size: 404 MB Simple search URL - Data acquisition method The data was converted from data of molecul...ar formulas and molecular weights in Basic Information ( http://dbarchive.biosciencedbc.j... Policy | Contact Us Molecular Formula and Molecular Weight - NBDC NikkajiRDF | LSDB Archive ...

Atoms, molecules and optical physics 1. Atoms and spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Hertel, Ingolf V.; Schulz, Claus-Peter

2015-09-01

This is the first volume of textbooks on atomic, molecular and optical physics, aiming at a comprehensive presentation of this highly productive branch of modern physics as an indispensable basis for many areas in physics and chemistry as well as in state of the art bio- and material-sciences. It primarily addresses advanced students (including PhD students), but in a number of selected subject areas the reader is lead up to the frontiers of present research. Thus even the active scientist is addressed. This volume 1 provides the canonical knowledge in atomic physics together with basics of modern spectroscopy. Starting from the fundamentals of quantum physics, the reader is familiarized in well structured chapters step by step with the most important phenomena, models and measuring techniques. The emphasis is always on the experiment and its interpretation, while the necessary theory is introduced from this perspective in a compact and occasionally somewhat heuristic manner, easy to follow even for beginners.

Terahertz Spectroscopy and Imaging

CERN Document Server

Zeitler, Axel; Kuwata-Gonokami, Makoto

2013-01-01

"This book presents the current state of knowledge in the field of terahertz spectroscopy, providing a comprehensive source of information for beginners and experienced researchers alike whose interests lie in this area. The book aims to explain the fundamental physics that underpins terahertz  technology and to describe its key applications. Highlights of scientific research in the field of terahertz science are also outlined in some chapters, providing an overview as well as giving an insight into future directions for research.  Over the past decade terahertz spectroscopy has developed into one of the most rapidly growing areas of its kind, gaining an important impact across a wide range of scientific disciplines. Due to substantial advances in femtosecond laser technology, terahertz time-domain spectroscopy (THz-TDS) has established itself as the dominant spectroscopic technique for experimental scientists interested in measurements at this frequency range. In solids and liquids THz radiation is in reso...

Spectroscopy and optical diagnostics for gases

CERN Document Server

Hanson, Ronald K; Goldenstein, Christopher S

2016-01-01

This text provides an introduction to the science that governs the interaction of light and matter (in the gas phase). It provides readers with the basic knowledge to exploit the light-matter interaction to develop quantitative tools for gas analysis (i.e. optical diagnostics) and understand and interpret the results of spectroscopic measurements. The authors pair the basics of gas‐phase spectroscopy with coverage of key optical diagnostic techniques utilized by practicing engineers and scientists to measure fundamental flow‐field properties. The text is organized to cover three sub‐topics of gas‐phase spectroscopy: (1) spectral line positions, (2) spectral line strengths, and (3) spectral lineshapes by way of absorption, emission, and scattering interactions. The latter part of the book describes optical measurement techniques and equipment. Key subspecialties include laser induced fluorescence, tunable laser absorption spectroscopy, and wavelength modulation spectroscopy. It is ideal for students an...

Long-Wave Infrared (LWIR) Molecular Laser-Induced Breakdown Spectroscopy (LIBS) Emissions of Thin Solid Explosive Powder Films Deposited on Aluminum Substrates.

Science.gov (United States)

Yang, Clayton S-C; Jin, Feng; Trivedi, Sudhir B; Brown, Ei E; Hommerich, Uwe; Tripathi, Ashish; Samuels, Alan C

2017-04-01

Thin solid films made of high nitro (NO 2 )/nitrate (NO 3 ) content explosives were deposited on sand-blasted aluminum substrates and then studied using a mercury-cadmium-telluride (MCT) linear array detection system that is capable of rapidly capturing a broad spectrum of atomic and molecular laser-induced breakdown spectroscopy (LIBS) emissions in the long-wave infrared region (LWIR; ∼5.6-10 µm). Despite the similarities of their chemical compositions and structures, thin films of three commonly used explosives (RDX, HMX, and PETN) studied in this work can be rapidly identified in the ambient air by their molecular LIBS emission signatures in the LWIR region. A preliminary assessment of the detection limit for a thin film of RDX on aluminum appears to be much lower than 60 µg/cm 2 . This LWIR LIBS setup is capable of rapidly probing and charactering samples without the need for elaborate sample preparation and also offers the possibility of a simultaneous ultraviolet visible and LWIR LIBS measurement.

Molecular structure of hybrid imino-chalcone in the solid state: X-ray diffraction, spectroscopy study and third-order nonlinear optical properties

Science.gov (United States)

Custodio, J. M. F.; Santos, F. G.; Vaz, W. F.; Cunha, C. E. P.; Silveira, R. G.; Anjos, M. M.; Campos, C. E. M.; Oliveira, G. R.; Martins, F. T.; da Silva, C. C.; Valverde, C.; Baseia, B.; Napolitano, H. B.

2018-04-01

A comprehensive structural study of the compound (2E)-1-((E)-4-(4-methoxybenzylideneamino)phenyl)-3-(4-methoxyphenyl)prop-2-en-1-one was carried out in this work. Single crystal X-ray diffraction (SCXRD), X-ray powder diffraction (XRPD), NMR, Raman and Infrared spectroscopies, and DFT calculations were performed for characterization of this iminochalcone hybrid. Intermolecular interactions were described by Hirshfeld surface analysis derived from crystal structure. Reactivity and intramolecular charge transfer were investigated using the frontier molecular orbitals and molecular electrostatic potential. In addition, we have calculated the Nonlinear Optical Properties at the CAM-B3LYP/6-311+g(d) level of theory in the presence of different solvents (gas-phase, acetone, chloroform, dichloromethane, dimethyl sulfoxide, ethanol, methanol, and water), being found meaningful NLO parameters for our compound. At last, there is a good agreement between calculated and experimental IR spectrum, allowing the assignment of some of normal vibrational modes of the iminochalcone hybrid.

Spectroscopy the key to the stars

CERN Document Server

Robinson, Keith

2007-01-01

This is the first non-technical book on spectroscopy written specifically for practical amateur astronomers. It includes all the science necessary for a qualitative understanding of stellar spectra, but avoids a mathematical treatment which would alienate many of its intended readers. Any amateur astronomer who carries out observational spectroscopy and who wants a non-technical account of the physical processes which determine the intensity and profile morphology of lines in stellar spectra will find this is the only book written specially for them. It is an ideal companion to existing books

Introduction to experimental infrared spectroscopy fundamentals and practical methods

CERN Document Server

Tasumi, Mitsuo; Ochiai, Shukichi

2014-01-01

Infrared spectroscopy is generally understood to mean the science of spectra relating to infrared radiation, namely electromagnetic waves, in the wavelength region occurring intermediately between visible light and microwaves. Measurements of infrared spectra have been providing useful information, for a variety of scientific research and industrial studies, for over half a century; this is set to continue in the foreseeable future. Introduction to Experimental Infrared Spectroscopy is intended to be a handy guide for those who have no, or limited, experience in infrared spectroscopi

Absorption Spectroscopy, Molecular Dynamics Calculations, and Multivariate Curve Resolution on the Phthalocyanine Aggregation

Energy Technology Data Exchange (ETDEWEB)

Ajloo, Davood; Ghadamgahi, Maryam; Shaheri, Freshte; Zarei, Kobra [Damghan Univ., Damghan (Iran, Islamic Republic of)

2014-05-15

Co(II)-tetrasulfonated phthalocyanine (CoTSP) is known to be aggregated to dimer at high concentration levels in water. A study on the aggregation of CoTSP using multivariate curve resolution analysis of the visible absorbance spectra over a concentration range of 30, 40 and 50 μM in the presence of dimethyl sulfoxide (DMSO), dimethyl formamide (DMF), acetonitrile (AN) and ethanol (EtOH) in the concentration range of 0 to 3.57 M is conducted. A hard modeling-based multivariate curve resolution method was applied to determine the dissociation constants of the CoTSP aggregates at various temperatures ranging from 25, 45 and 65 .deg. C and in the presence of various co-solvents. Dissociation constant for aggregation was increased and then decrease by temperature and concentration of phthalocyanine, respectively. Utilizing the vant Hoff relation, the enthalpy and entropy of the dissociation equilibriums were calculated. For the dissociation of both aggregates, the enthalpy and entropy changes were positive and negative, respectively. Molecular dynamics simulation of cosolvent effect on CoTSP aggregation was done to confirm spectroscopy results. Results of radial distribution function (RDF), root mean square deviation (RMSD) and distance curves confirmed more effect of polar solvent to decrease monomer formation.

Absorption Spectroscopy, Molecular Dynamics Calculations, and Multivariate Curve Resolution on the Phthalocyanine Aggregation

International Nuclear Information System (INIS)

Ajloo, Davood; Ghadamgahi, Maryam; Shaheri, Freshte; Zarei, Kobra

2014-01-01

Co(II)-tetrasulfonated phthalocyanine (CoTSP) is known to be aggregated to dimer at high concentration levels in water. A study on the aggregation of CoTSP using multivariate curve resolution analysis of the visible absorbance spectra over a concentration range of 30, 40 and 50 μM in the presence of dimethyl sulfoxide (DMSO), dimethyl formamide (DMF), acetonitrile (AN) and ethanol (EtOH) in the concentration range of 0 to 3.57 M is conducted. A hard modeling-based multivariate curve resolution method was applied to determine the dissociation constants of the CoTSP aggregates at various temperatures ranging from 25, 45 and 65 .deg. C and in the presence of various co-solvents. Dissociation constant for aggregation was increased and then decrease by temperature and concentration of phthalocyanine, respectively. Utilizing the vant Hoff relation, the enthalpy and entropy of the dissociation equilibriums were calculated. For the dissociation of both aggregates, the enthalpy and entropy changes were positive and negative, respectively. Molecular dynamics simulation of cosolvent effect on CoTSP aggregation was done to confirm spectroscopy results. Results of radial distribution function (RDF), root mean square deviation (RMSD) and distance curves confirmed more effect of polar solvent to decrease monomer formation

Interaction of Aldehyde dehydrogenase with acetaminophen as examined by spectroscopies and molecular docking

Directory of Open Access Journals (Sweden)

Ayodele O. Kolawole

2017-07-01

Full Text Available The interaction of acetaminophen, a non-substrate anionic ligand, with Aldehyde Dehydrogenase was studied by fluorescence, UV–Vis absorption, and circular dichroism spectroscopies under simulated physiological conditions. The fluorescence spectra and data generated showed that acetaminophen binding to ALDH is purely dynamic quenching mechanism. The acetaminophen-ALDH is kinetically rapid reversible interaction with a binding constant, Ka, of 4.91×103 L mol−1. There was an existence of second binding site of ALDH for acetaminophen at saturating acetaminophen concentration. The binding sites were non-cooperative. The thermodynamic parameters obtained suggest that Van der Waal force and hydrogen bonding played a major role in the binding of acetaminophen to ALDH. The interaction caused perturbation of the ALDH structures with an obvious reduction in the α-helix. The binding distance of 4.43 nm was obtained between Acetaminophen and ALDH. Using Ficoll 400 as macro-viscosogen and glycerol as micro-viscosogen, Stoke-Einstein empirical plot demonstrated that acetaminophen-ALDH binding was diffusion controlled. Molecular docking showed the participation of some amino acids in the complex formation with −5.3 kcal binding energy. With these, ALDH might not an excipient detoxifier of acetaminophen but could be involved in its pegylation/encapsulation.

High resolution neutron spectroscopy - a tool for the investigation of dynamics of polymers and soft matter

International Nuclear Information System (INIS)

Monkenbusch, M.; Richter, D.

2007-01-01

Neutron scattering, with the ability to vary the contrast of molecular items by hydrogen/deuterium exchanges, is an invaluable tool for soft matter research. Besides the structural information on the mesoscopic scale that is obtained by diffraction methods like small angle neutron scattering, the slow dynamics of molecular motion on mesoscopic scale is accessible by high resolution neutron spectroscopy. The basic features of neutron backscattering spectroscopy, and in particular neutron spin-echo spectroscopy, are presented, in combination with illustrations of results from polymer melt dynamics to protein dynamics which are obtained by these techniques. (authors)

Role of Infrared Spectroscopy and Imaging in Cancer Diagnosis.

Science.gov (United States)

Kumar, Saroj; Srinivasan, Alagiri; Nikolajeff, Fredrik

2018-01-01

Cancer is a major global health issue. It causes extensive individual suffering and gives a huge burden on the health care in society. Despite extensive research and different tools have been developed it still remains a challenge for early detection of this disease. FTIR imaging has been used to diagnose and differentiate the molecular differences between normal and diseased tissues. Fourier Transform Infrared Spectroscopy (FTIR) is able to measure biochemical changes in tissue, cell and biofluids based on the vibrational signature of their components. This technique enables to the distribution and structure of lipids, proteins, nucleic acids as well as other metabolites. These differences depended on the type and the grade of cancer. We emphasize here, that the FTIR spectroscopy and imaging can be considered as a promising technique and will find its place on the detection of this dreadful disease because of high sensitivity, accuracy and inexpensive technique. Now the medical community started using and accepting this technique for early stage cancer detection. We discussed this technique and the several challenges in its application for the diagnosis of cancer in regards of sample preparations, data interpretation, and data analysis. The sensitivity of chemotherapy drugs on individual specific has also discussed. So far progressed has done with the FTIR imaging in understanding of cancer disease pathology. However, more research is needed in this field and it is necessary to understand the morphology and biology of the sample before using the spectroscopy and imaging because invaluable information to be figured out. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Astronomical Spectroscopy A Short History

Indian Academy of Sciences (India)

Home; Journals; Resonance – Journal of Science Education; Volume 3; Issue 5. Astronomical Spectroscopy A Short History. J C Bhattacharyya. General Article Volume 3 Issue 5 May 1998 pp 24-29. Fulltext. Click here to view fulltext PDF. Permanent link: https://www.ias.ac.in/article/fulltext/reso/003/05/0024-0029 ...

MDM2–MDM4 molecular interaction investigated by atomic force spectroscopy and surface plasmon resonance

Directory of Open Access Journals (Sweden)

Moscetti I

2016-08-01

Full Text Available Ilaria Moscetti,1 Emanuela Teveroni,2,3 Fabiola Moretti,3 Anna Rita Bizzarri,1 Salvatore Cannistraro1 1Biophysics and Nanoscience Centre, Department DEB, Università della Tuscia, Viterbo, Italy; 2Department of Endocrinology and Metabolism, Università Cattolica di Roma, Roma, Italy; 3Institute of Cell Biology and Neurobiology, Consiglio Nazionale delle Ricerche (CNR, Roma, Italy Abstract: Murine double minute 2 (MDM2 and 4 (MDM4 are known as the main negative regulators of p53, a tumor suppressor. They are able to form heterodimers that are much more effective in the downregulation of p53. Therefore, the MDM2–MDM4 complex could be a target for promising therapeutic restoration of p53 function. To this aim, a deeper understanding of the molecular mechanisms underlining the heterodimerization is needed. The kinetic and thermodynamic characterization of the MDM2–MDM4 complex was performed with two complementary approaches: atomic force spectroscopy and surface plasmon resonance. Both techniques revealed an equilibrium dissociation constant (KD in the micromolar range for the MDM2–MDM4 heterodimer, similar to related complexes involved in the p53 network. Furthermore, the MDM2–MDM4 complex is characterized by a relatively high free energy, through a single energy barrier, and by a lifetime in the order of tens of seconds. New insights into the MDM2–MDM4 interaction could be highly important for developing innovative anticancer drugs focused on p53 reactivation. Keywords: MDM2, MDM4, atomic force spectroscopy, surface plasmon resonance

Life sciences and environmental sciences

Energy Technology Data Exchange (ETDEWEB)

1992-02-01

The DOE laboratories play a unique role in bringing multidisciplinary talents -- in biology, physics, chemistry, computer sciences, and engineering -- to bear on major problems in the life and environmental sciences. Specifically, the laboratories utilize these talents to fulfill OHER's mission of exploring and mitigating the health and environmental effects of energy use, and of developing health and medical applications of nuclear energy-related phenomena. At Lawrence Berkeley Laboratory (LBL) support of this mission is evident across the spectrum of OHER-sponsored research, especially in the broad areas of genomics, structural biology, basic cell and molecular biology, carcinogenesis, energy and environment, applications to biotechnology, and molecular, nuclear and radiation medicine. These research areas are briefly described.

Life sciences and environmental sciences

Energy Technology Data Exchange (ETDEWEB)

1992-02-01

The DOE laboratories play a unique role in bringing multidisciplinary talents -- in biology, physics, chemistry, computer sciences, and engineering -- to bear on major problems in the life and environmental sciences. Specifically, the laboratories utilize these talents to fulfill OHER`s mission of exploring and mitigating the health and environmental effects of energy use, and of developing health and medical applications of nuclear energy-related phenomena. At Lawrence Berkeley Laboratory (LBL) support of this mission is evident across the spectrum of OHER-sponsored research, especially in the broad areas of genomics, structural biology, basic cell and molecular biology, carcinogenesis, energy and environment, applications to biotechnology, and molecular, nuclear and radiation medicine. These research areas are briefly described.

General survey of recent development of photoemission spectroscopy

International Nuclear Information System (INIS)

Edamoto, Kazuyuki

1994-01-01

On the present state of the recent development of photoemission spectroscopy, by limiting the topics to the development of the spectroscopy proper and the development contributing to the progress of surface science, general explanation is made. As to the development that enabled to heighten spectrum resolution, surface core-level shift and the precise measurement of the Fermi surface of surface level are described, showing the example. Also a number of the developments which enabled the utilization of the light source, of which the wavelength is variable, and which was brought about by synchrotron radiation beam, were mentioned. Besides, spin polarized photoelectron spectroscopy, the development of photoelectron microscope and others are outlined. Photoemission spectroscopy is very useful for analyzing the electron condition of solid surfaces. There are two factors in heightening core level spectrum resolution, namely, heightening the resolution of an electron energy analyzer proper and the utilization of synchrotron radiation as a light source. High resolution core-level spectra, angle-resolved photoemission spectroscopy, and as the light source of which the wavelength is variable, resonance photoemission spectroscopy, constant initial state spectroscopy and soft X-ray photoemission spectroscopy, and as the recently developed spectroscopy, spin polarized photoemission spectroscopy, Auger photoelectron coincidence spectroscopy and photoelectron microscope are explained. (K.I.)

European Virtual Atomic And Molecular Data Center - VAMDC

Science.gov (United States)

Dimitrijevic, M. S.; Sahal-Brechot, S.; Kovacevic, A.; Jevremovic, D.; Popovic, L. C.

2010-07-01

Reliable atomic and molecular data are of great importance for different applications in astrophysics, atmospheric physics, fusion, environmental sciences, combustion chemistry, and in industrial applications from plasmas and lasers to lighting. Currently, very important resources of such data are highly fragmented, presented in different, nonstandardized ways, available through a variety of highly specialized and often poorly documented interfaces, so that the full exploitation of all their scientific worth is limited, hindering research in many topics like e.g. the characterization of extrasolar planets, understanding the chemistry of our local solar system and of the wider universe, the study of the terrestrial atmosphere and quantification of climate change; the development of the fusion rersearch, etc. The Virtual Atomic and Molecular Data Centre (http://www.vamdc.eu, VAMDC) is an European Union funded FP7 project aiming to build a secure, documented, flexible and interoperable e-science environment-based interface to existing atomic and molecular data. It will also provide a forum for training potential users and dissemination of expertise worldwide. Partners in the Consortium of the Project are: 1) Centre National de Recherche Scientifique - CNRS (Paris, Reims, Grenoble, Bordeaux, Dijon, Toulouse); 2) The Chancellor, Masters and Scholars of the University of Cambridge - CMSUC; 3) University College London - UCL; 4) Open University - OU; (Milton Keynes, England); 5) Universitaet Wien - UNIVIE; 6) Uppsala Universitet - UU; 7) Universitaet zu Koeln - KOLN; 8) Istituto Nazionale di Astrofisica - INAF (Catania, Cagliari); 9) Queen's University Belfast - QUB; 10) Astronomska Opservatorija - AOB (Belgrade, Serbia); 11) Institute of Spectroscopy RAS - ISRAN (Troitsk, Russia); 12) Russian Federal Nuclear Center - All-Russian Institute of Technical Physics - RFNC-VNIITF (Snezhinsk, Chelyabinsk Region, Russia; 13) Institute of Atmospheric Optics - IAO (Tomsk, Russia

Self-assembly of chiral molecular polygons.

Science.gov (United States)

Jiang, Hua; Lin, Wenbin

2003-07-09

Treatment of 2,2'-diacetyl-1,1'-binaphthyl-6,6'-bis(ethyne), L-H2, with 1 equiv of trans-Pt(PEt3)2Cl2 led to a mixture of different sizes of chiral metallocycles [trans-(PEt3)2Pt(L)]n (n = 3-8, 1-6). Each of the chiral molecular polygons 1-6 was purified by silica gel column chromatography and characterized by 1H, 13C{1H}, and 31P{1H} NMR spectroscopy, MS, IR, UV-vis, and circular dichroism spectroscopies, and microanalysis. The presence of tunable cavities (1.4-4.3 nm) and chiral functionalities in these molecular polygons promises to make them excellent receptors for a variety of guests.

Molecular Theory of the Living Cell Concepts, Molecular Mechanisms, and Biomedical Applications

CERN Document Server

Ji, Sungchul

2012-01-01

This book presents a comprehensive molecular theory of the living cell based on over thirty concepts, principles and laws imported from thermodynamics, statistical mechanics, quantum mechanics, chemical kinetics, informatics, computer science, linguistics, semiotics, and philosophy. The author formulates physically, chemically and enzymologically realistic molecular mechanisms to account for the basic living processes such as ligand-receptor interactions, protein folding, single-molecule enzymic catalysis, force-generating mechanisms in molecular motors, signal transduction, regulation of the genome-wide RNA metabolism, morphogenesis, the micro-macro coupling in coordination dynamics, the origin of life, and the mechanisms of biological evolution itself. Possible solutions to basic and practical problems facing contemporary biology and biomedical sciences have been suggested, including pharmacotheragnostics and personalized medicine.

Surface Chemistry and Spectroscopy of Chromium in Inorganic Oxides

NARCIS (Netherlands)

Weckhuysen, B.M.; Wachs, I.E.; Schoonheydt, R.A.

1996-01-01

Focuses on the surface chemistry and spectroscopy of chromium in inorganic oxides. Characterization of the molecular structures of chromium; Mechanics of hydrogenation-dehydrogenation reactions; Mobility and reactivity on oxidic surfaces.

MDM2-MDM4 molecular interaction investigated by atomic force spectroscopy and surface plasmon resonance.

Science.gov (United States)

Moscetti, Ilaria; Teveroni, Emanuela; Moretti, Fabiola; Bizzarri, Anna Rita; Cannistraro, Salvatore

Murine double minute 2 (MDM2) and 4 (MDM4) are known as the main negative regulators of p53, a tumor suppressor. They are able to form heterodimers that are much more effective in the downregulation of p53. Therefore, the MDM2-MDM4 complex could be a target for promising therapeutic restoration of p53 function. To this aim, a deeper understanding of the molecular mechanisms underlining the heterodimerization is needed. The kinetic and thermodynamic characterization of the MDM2-MDM4 complex was performed with two complementary approaches: atomic force spectroscopy and surface plasmon resonance. Both techniques revealed an equilibrium dissociation constant (KD ) in the micromolar range for the MDM2-MDM4 heterodimer, similar to related complexes involved in the p53 network. Furthermore, the MDM2-MDM4 complex is characterized by a relatively high free energy, through a single energy barrier, and by a lifetime in the order of tens of seconds. New insights into the MDM2-MDM4 interaction could be highly important for developing innovative anticancer drugs focused on p53 reactivation.

In vivo Molecular Evaluation of Guinea Pig Skin Incisions Healing after Surgical Suture and Laser Tissue Welding Using Raman Spectroscopy

Science.gov (United States)

Alimova, A.; Chakraverty, R.; Muthukattil, R.; Elder, S.; Katz, A.; Sriramoju, V.; Lipper, Stanley; Alfano, R. R.

2009-01-01

The healing process in guinea pig skin following surgical incisions was evaluated at the molecular level, in vivo, by the use of Raman spectroscopy. After the incisions were closed either by suturing or by laser tissue welding (LTW), differences in the respective Raman spectra were identified. The study determined that the ratio of the Raman peaks of the amide III (1247 cm−1) band to a peak at 1326 cm−1 (the superposition of elastin and keratin bands) can be used to evaluate the progression of wound healing. Conformational changes in the amide I band (1633 cm−1 to 1682 cm−1) and spectrum changes in the range of 1450 cm−1 to 1520 cm−1 were observed in LTW and sutured skin. The stages of the healing process of the guinea pig skin following LTW and suturing were evaluated by Raman spectroscopy, using histopathology as the gold standard. LTW skin demonstrated better healing than sutured skin, exhibiting minimal hyperkeratosis, minimal collagen deposition, near-normal surface contour, and minimal loss of dermal appendages. A wavelet decomposition-reconstruction baseline correction algorithm was employed to remove the fluorescence wing from the Raman spectra. PMID:19581109

Remote Laser Evaporative Molecular Absorption Spectroscopy Sensor System

Data.gov (United States)

National Aeronautics and Space Administration — We propose a sensor system capable of remotely probing the molecular composition of cold solar system targets (asteroids, comets, planets, moons), such as from a...

Principles and applications of force spectroscopy using atomic force microscopy

Energy Technology Data Exchange (ETDEWEB)

Kim, Young Kyu; Kim, Woong; Park, Joon Won [Dept. of Chemistry, Pohang University of Science and Technology, Pohang (Korea, Republic of)

2016-12-15

Single-molecule force spectroscopy is a powerful technique for addressing single molecules. Unseen structures and dynamics of molecules have been elucidated using force spectroscopy. Atomic force microscope (AFM)-based force spectroscopy studies have provided picoNewton force resolution, subnanometer spatial resolution, stiffness of substrates, elasticity of polymers, and thermodynamics and kinetics of single-molecular interactions. In addition, AFM has enabled mapping the distribution of individual molecules in situ, and the quantification of single molecules has been made possible without modification or labeling. In this review, we describe the basic principles, sample preparation, data analysis, and applications of AFM-based force spectroscopy and its future.

UV-Vis Ratiometric Resonance Synchronous Spectroscopy for Determination of Nanoparticle and Molecular Optical Cross Sections.

Science.gov (United States)

Nettles, Charles B; Zhou, Yadong; Zou, Shengli; Zhang, Dongmao

2016-03-01

Demonstrated herein is a UV-vis Ratiometric Resonance Synchronous Spectroscopic (R2S2, pronounced as "R-two-S-two" for simplicity) technique where the R2S2 spectrum is obtained by dividing the resonance synchronous spectrum of a NP-containing solution by the solvent resonance synchronous spectrum. Combined with conventional UV-vis measurements, this R2S2 method enables experimental quantification of the absolute optical cross sections for a wide range of molecular and nanoparticle (NP) materials that range optically from pure photon absorbers or scatterers to simultaneous photon absorbers and scatterers, simultaneous photon absorbers and emitters, and all the way to simultaneous photon absorbers, scatterers, and emitters in the UV-vis wavelength region. Example applications of this R2S2 method were demonstrated for quantifying the Rayleigh scattering cross sections of solvents including water and toluene, absorption and resonance light scattering cross sections for plasmonic gold nanoparticles, and absorption, scattering, and on-resonance fluorescence cross sections for semiconductor quantum dots (Qdots). On-resonance fluorescence quantum yields were quantified for the model molecular fluorophore Eosin Y and fluorescent Qdots CdSe and CdSe/ZnS. The insights and methodology presented in this work should be of broad significance in physical and biological science research that involves photon/matter interactions.

Fellowship | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Fellowship. Fellow Profile. Elected: 2007 Section: Plant Sciences. Grover, Prof. Anil Ph.D. (IARI), FNASc, FNAAS, FNA. Date of birth: 15 August 1958. Specialization: Plant Abiotic Stress Responses, Plant Biotechnology, Molecular Biology and Crop Sciences Address: Professor, Department of Plant Molecular Biology, ...

Journal of Chemical Sciences | Indian Academy of Sciences

Indian Academy of Sciences (India)

National Engineering Research Center for Integrated Utilization of Salt Lake Resource, East China University of Science and Technology, Meilong Road 130, Shanghai 200237, China; Van 't Hoff Institute for Molecular Sciences & Amsterdam Center for Multiscale Modeling, University of Amsterdam, 1098 XH Amsterdam, ...

Journal of Chemical Sciences | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Chemical Sciences. M PRASANTHI. Articles written in Journal of Chemical Sciences. Volume 129 Issue 5 May 2017 pp 515-531 Regular Article. Assessing therapeutic potential of molecules: molecular property diagnostic suite for tuberculosis (MPDS) · ANAMIKA SINGH GAUR ANSHU ...

Journal of Chemical Sciences | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Chemical Sciences. SRIDHARA JANARDHAN. Articles written in Journal of Chemical Sciences. Volume 129 Issue 5 May 2017 pp 515-531 Regular Article. Assessing therapeutic potential of molecules: molecular property diagnostic suite for tuberculosis (MPDS) · ANAMIKA SINGH GAUR ...

Journal of Chemical Sciences | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Chemical Sciences. Kishalay Bhar. Articles written in Journal of Chemical Sciences. Volume 125 Issue 4 July 2013 pp 715-721. Syntheses, molecular and crystalline architectures, and luminescence behaviour of terephthalate bridged heptacoordinated dinuclear lead(II) complexes containing a ...

Journal of Chemical Sciences | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Chemical Sciences. DIPU SUTRADHAR. Articles written in Journal of Chemical Sciences. Volume 128 Issue 9 September 2016 pp 1377-1384 Regular Article. Two new hexacoordinated coordination polymers of cadmium(II) containing bridging units only: Syntheses, structures and molecular ...

Spectroscopy, scattering, and KK molecules

Energy Technology Data Exchange (ETDEWEB)

Weinstein, J. [Univ. of Mississippi, University, MS (United States)

1994-04-01

The author presents a pedagogical description of a new theoretical technique, based on the multichannel Schroedinger equation, for simultaneously applying the quark model to both meson spectroscopy and meson-meson scattering. This is an extension of an earlier analysis which led to the prediction that the f{sub o}(975) and a{sub o}(980) scalar mesons are K{bar K} molecular states.

Optical Spectroscopy Of Charged Quantum Dot Molecules

Science.gov (United States)

Scheibner, M.; Bracker, A. S.; Stinaff, E. A.; Doty, M. F.; Gammon, D.; Ponomarev, I. V.; Reinecke, T. L.; Korenev, V. L.

2007-04-01

Coupling between two closely spaced quantum dots is observed by means of photoluminescence spectroscopy. Hole coupling is realized by rational crystal growth and heterostructure design. We identify molecular resonances of different excitonic charge states, including the important case of a doubly charged quantum dot molecule.

A Statistical Approach to Exoplanetary Molecular Spectroscopy Using Spitzer Eclipses

Science.gov (United States)

Deming, Drake; Garhart, Emily; Burrows, Adam; Fortney, Jonathan; Knutson, Heather; Todorov, Kamen

2018-01-01

Secondary eclipses of exoplanets observed using the Spitzer Space Telescope measure the total emission emergent from exoplanetary atmospheres integrated over broad photometric bands. Spitzer photometry is excellent for measuring day side temperatures, but is less well suited to the detection of molecular absorption or emission features. Even for very hot exoplanets, it can be difficult to attain the accuracy on eclipse depth that is needed to unambiguously interpret the Spitzer results in terms of molecular absorption or emission. However, a statistical approach, wherein we seek deviations from a simple blackbody planet as a function of the planet's equilibrium temperature, shows promise for defining the nature and strength of molecular absorption in ensembles of planets. In this paper, we explore such an approach using secondary eclipses observed for tens of hot exoplanets during Spitzer's Cycles 10, 12, and 13. We focus on the possibility that the hottest planets exhibit molecular features in emission, due to temperature inversions.

S&MPO - An information system for ozone spectroscopy on the WEB

Science.gov (United States)

Babikov, Yurii L.; Mikhailenko, Semen N.; Barbe, Alain; Tyuterev, Vladimir G.

2014-09-01

Spectroscopy and Molecular Properties of Ozone ("S&MPO") is an Internet accessible information system devoted to high resolution spectroscopy of the ozone molecule, related properties and data sources. S&MPO contains information on original spectroscopic data (line positions, line intensities, energies, transition moments, spectroscopic parameters) recovered from comprehensive analyses and modeling of experimental spectra as well as associated software for data representation written in PHP Java Script, C++ and FORTRAN. The line-by-line list of vibration-rotation transitions and other information is organized as a relational database under control of MySQL database tools. The main S&MPO goal is to provide access to all available information on vibration-rotation molecular states and transitions under extended conditions based on extrapolations of laboratory measurements using validated theoretical models. Applications for the S&MPO may include: education/training in molecular physics, radiative processes, laser physics; spectroscopic applications (analysis, Fourier transform spectroscopy, atmospheric optics, optical standards, spectroscopic atlases); applications to environment studies and atmospheric physics (remote sensing); data supply for specific databases; and to photochemistry (laser excitation, multiphoton processes). The system is accessible via Internet on two sites: http://smpo.iao.ru and http://smpo.univ-reims.fr.

Spectroscopy of Charge Carriers and Traps in Field-Doped Single Crystal Organic Semiconductors

Energy Technology Data Exchange (ETDEWEB)

Zhu, Xiaoyang [Columbia Univ., New York, NY (United States); Frisbie, Daniel [Univ. of Minnesota, Minneapolis, MN (United States)

2017-03-31

The proposed research aims to achieve quantitative, molecular level understanding of charge carriers and traps in field-doped crystalline organic semiconductors via in situ linear and nonlinear optical spectroscopy, in conjunction with transport measurements and molecular/crystal engineering.

In-Situ Measurement of Chirality of Molecules and Molecular Assemblies with Surface Nonlinear Spectroscopy

International Nuclear Information System (INIS)

Wang, Hongfei

2012-01-01

Developments in quantitative measurement and analysis in nonlinear surface spectroscopy, namely, second harmonic generation linear dichroism (SHG-LD) and sum frequency generation vibrational spectroscopy linear dichroism (SFG-VS-LD), provide new opportunities for probing the surface chirality of monolayers and thin films. In this book chapter, the up-to-date theoretical background and experimental methodology, as well as examples and future perspectives on the developments with surface nonlinear spectroscopy in surface chirality studies are to be summarized and outlined for general readers.

Journal of Chemical Sciences | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Chemical Sciences. M RAM VIVEK. Articles written in Journal of Chemical Sciences. Volume 129 Issue 5 May 2017 pp 515-531 Regular Article. Assessing therapeutic potential of molecules: molecular property diagnostic suite for tuberculosis (MPDS) · ANAMIKA SINGH GAUR ANSHU ...

Journal of Chemical Sciences | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Chemical Sciences. Asim Bhaumik. Articles written in Journal of Chemical Sciences. Volume 114 Issue 4 August 2002 pp 451-460. Mesoporous titanium phosphates and related molecular sieves: Synthesis, characterization and applications · Asim Bhaumik · More Details Abstract Fulltext PDF.

Journal of Chemical Sciences | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Chemical Sciences. Charusita Chakravarty. Articles written in Journal of Chemical Sciences. Volume 121 Issue 5 September 2009 pp 913-919. Evaluation of collective transport properties of ionic melts from molecular dynamics simulations · Manish Agarwal Charusita Chakravarty · More Details ...

Journal of Chemical Sciences | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Chemical Sciences. T SHANMUGANATHAN. Articles written in Journal of Chemical Sciences. Volume 129 Issue 1 January 2017 pp 117-130 Regular Article. Synthesis, in vitro anti-inflammatory activity and molecular docking studies of novel 4,5-diarylthiophene-2-carboxamide derivatives.

High resolution neutron spectroscopy - a tool for the investigation of dynamics of polymers and soft matter; La spectroscopie de neutrons a haute resolution-un outil pour l'etude de la dynamique des polymeres et de la matiere molle

Energy Technology Data Exchange (ETDEWEB)

Monkenbusch, M.; Richter, D. [Institut fur Festkorperforschung (IFF), Forschungszentrum Julich, Julich (Germany)

2007-09-15

Neutron scattering, with the ability to vary the contrast of molecular items by hydrogen/deuterium exchanges, is an invaluable tool for soft matter research. Besides the structural information on the mesoscopic scale that is obtained by diffraction methods like small angle neutron scattering, the slow dynamics of molecular motion on mesoscopic scale is accessible by high resolution neutron spectroscopy. The basic features of neutron backscattering spectroscopy, and in particular neutron spin-echo spectroscopy, are presented, in combination with illustrations of results from polymer melt dynamics to protein dynamics which are obtained by these techniques. (authors)

Raman spectroscopy in comparative investigations of mechanisms of binding of three molecular probes - fluorescein, eosin, and erythrosin - to human serum albumin

Science.gov (United States)

Vlasova, I. M.; Saletsky, A. M.

2008-11-01

The comparative analysis of binding of three molecular fluorescent probes (fluorescein, eosin, and erythrosin), belonging to one homologous family, to human serum albumin (HSA) is made by Raman spectroscopy method. The binding of all three probes to binding Center I of HSA is registered. The character of binding of initial probe of the given homologous family - fluorescein - to protein differs from character of binding of its halogen-derivatives (eosin and erythrosin) to protein. The differences in binding of these three probes to HSA are determined by value of electronegativity of atoms of lateral radicals in structural formulas of probes and, therefore, by value of pK of their ionized groups.

Development of atomic spectroscopy methods in geological institutes of Faculty of Natural Sciences Comenius University and Slovak Academy of Science

International Nuclear Information System (INIS)

Medved, E.

1998-01-01

Development of atomic spectrochemistry methods in Geological Institute of Faculty of Natural Sciences, Comenius University (GI FNS CU) is connected with its establishment in 1957. Its instrumental equipment and location resulted from the already existing Laboratory in the Chair for Mineralogy and Crystallography of FNS CU. In Geological Institute of Slovak Academy of Science (GI SAS) the development of atomic spectroscopy methods started later, only since 1963, when the Member of Academy, Prof. RNDr. B. Cambel, DrSc. became its director. In both institutes the methods of atomic emission spectrography were used as first. A new quality in the development started since 1969 when the Institutes moved to common buildings in Petrzalka (Bratislava), the first atomic absorption spectrometers were acquired and the Institutes were 'strengthened' by coming of Prof. Ing. E. Plsko, DrSc. In the following years the Institutes started to collaborate with some other organisations which were equipped with new facilities, e.g. in 1975 with X-ray fluorescence spectrometer, electron microprobe and in 1985 with inductively coupled plasma atomic emission spectrometer. This enabled to improve essentially the quality of research activities of both institutes in the chemical characterisation of geological materials, as well as in pedagogical work (students practice, diploma works and dissertations). In the present time characterized by new economic conditions a reduction of GI SAS laboratory activities has been realised. The laboratories of the GI FNS CU have, thanks to their director Ing. V. Stresko, PhD. shown also hence-forward a rich research, pedagogical and society activities what can be documented by numerous publications, citations, obtained awards, representations in professional societies and commissions, local and foreign advisory boards, accreditation boards etc. (author)

Band offsets and growth mode of molecular beam epitaxy grown MgO (111) on GaN (0002) by x-ray photoelectron spectroscopy

Science.gov (United States)

Craft, H. S.; Collazo, R.; Losego, M. D.; Mita, S.; Sitar, Z.; Maria, J.-P.

2007-10-01

MgO is a proposed dielectric for use as a tunneling barrier in devices integrating GaN and ferroelectric oxides. In this study, we present data regarding the growth mode and band offsets of MgO grown epitaxially on GaN (0002) surfaces using molecular beam epitaxy. Using in situ x-ray photoelectron spectroscopy (XPS) and molecular beam epitaxy, we determine, from sequential growth experiments, that the growth of MgO proceeds via the Volmer-Weber (three-dimensional) mode, and full coalescence of the film does not occur until approximately 12nm of MgO has been deposited. The observation of a three-dimensional growth mode is in agreement with previously published data. For the valence band offset, we find a value of 1.2±0.2eV, which corresponds to a 3.2eV conduction band offset. XPS measurements suggest a chemically abrupt interface and no effect on band lineup due to the slow coalescence behavior.

Band offsets and growth mode of molecular beam epitaxy grown MgO (111) on GaN (0002) by x-ray photoelectron spectroscopy

International Nuclear Information System (INIS)

Craft, H. S.; Collazo, R.; Losego, M. D.; Mita, S.; Sitar, Z.; Maria, J.-P.

2007-01-01

MgO is a proposed dielectric for use as a tunneling barrier in devices integrating GaN and ferroelectric oxides. In this study, we present data regarding the growth mode and band offsets of MgO grown epitaxially on GaN (0002) surfaces using molecular beam epitaxy. Using in situ x-ray photoelectron spectroscopy (XPS) and molecular beam epitaxy, we determine, from sequential growth experiments, that the growth of MgO proceeds via the Volmer-Weber (three-dimensional) mode, and full coalescence of the film does not occur until approximately 12 nm of MgO has been deposited. The observation of a three-dimensional growth mode is in agreement with previously published data. For the valence band offset, we find a value of 1.2±0.2 eV, which corresponds to a 3.2 eV conduction band offset. XPS measurements suggest a chemically abrupt interface and no effect on band lineup due to the slow coalescence behavior

NMR spectroscopy

International Nuclear Information System (INIS)

Gruenert, J.

1989-01-01

The book reviews the applications of NMR-spectroscopy in medicine and biology. The first chapter of about 40 pages summarizes the history of development and explains the chemical and physical fundamentals of this new and non-invasive method in an easily comprehensible manner. The other chapters summarize diagnostic results obtained with this method in organs and tissues, so that the reader will find a systematic overview of the available findings obtained in the various organ systems. It must be noted, however, that ongoing research work and new insight quite naturally will necessitate corrections to be done, as is the case here with some biochemical interpretations which would need adjustment to latest research results. NMR-spectroscopy is able to measure very fine energy differences on the molecular level, and thus offers insight into metabolic processes, with the advantage that there is no need of applying ionizing radiation in order to qualitatively or quantitatively analyse the metabolic processes in the various organ systems. (orig./DG) With 40 figs., 4 tabs [de

Sum frequency generation for surface vibrational spectroscopy

International Nuclear Information System (INIS)

Hunt, J.H.; Guyot-Sionnest, P.; Shen, Y.R.

1987-01-01

Surface vibrational spectroscopy is one of the best means for characterizing molecular adsorbates. For this reason, many techniques have been developed in the past. However, most of them suffer from poor sensitivity, low spectral and temporal resolution, and applications limited to vacuum solid interfaces. Recently, the second harmonic generation (SHG) technique was proved repeatedly to be a simple but versatile surface probe. It is highly sensitive and surface specific; it is also capable of achieving high temporal, spatial, and spectral resolution. Being an optical technique, it can be applied to any interface accessible by light. The only serious drawback is its lack of molecular selectivity. An obvious remedy is the extension of the technique to IR-visible sum frequency generation (SFG). Surface vibrational spectroscopy with submonolayer sensitivity is then possible using SFG with the help of a tunable IR laser. The authors report here an SFG measurement of the C-H stretch vibration of monolayers of molecules at air-solid and air-liquid interfaces

Journal of Chemical Sciences | Indian Academy of Sciences

Indian Academy of Sciences (India)

Further, these modes are investigated by FT-IR and FT-Raman spectroscopy in the range of 4000–400 cm−1. The optimized molecular geometry and computed vibrational spectra are compared with experimental results, which show significant agreement. The natural bond orbital (NBO) analysis was carried out to interpret ...

Well-Defined Polyethylene-Based Random, Block, and Bilayered Molecular Cobrushes

KAUST Repository

Zhang, Hefeng; Zhang, Zhen; Gnanou, Yves; Hadjichristidis, Nikolaos

2015-01-01

by anionic polymerization. Proton nuclear magnetic resonance spectroscopy (1H NMR) and high-temperature gel permeation chromatography (HT-GPC) were used to imprint the molecular characteristics of all macromonomers and molecular brushes and differential

Journal of Chemical Sciences | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Chemical Sciences. SABIHA FATIMA. Articles written in Journal of Chemical Sciences. Volume 128 Issue 7 July 2016 pp 1163-1173 Regular Article. Molecular docking, MM/GBSA and 3D-QSAR studies on EGFR inhibitors · RAJU BATHINI SREE KANTH SIVAN SABIHA FATIMA VIJJULATHA ...

Journal of Chemical Sciences | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Chemical Sciences. Tapta Kanchan Roy. Articles written in Journal of Chemical Sciences. Volume 121 Issue 5 September 2009 pp 805-810. Effective harmonic oscillator description of anharmonic molecular vibrations · Tapta Kanchan Roy M Durga Prasad · More Details Abstract Fulltext PDF.

Journal of Chemical Sciences | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Chemical Sciences. RAJU BATHINI. Articles written in Journal of Chemical Sciences. Volume 128 Issue 7 July 2016 pp 1163-1173 Regular Article. Molecular docking, MM/GBSA and 3D-QSAR studies on EGFR inhibitors · RAJU BATHINI SREE KANTH SIVAN SABIHA FATIMA VIJJULATHA ...

Journal of Chemical Sciences | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Chemical Sciences. Navneet Kaur. Articles written in Journal of Chemical Sciences. Volume 126 Issue 1 January 2014 pp 49-54. Anthraquinone-based demultiplexer and other multiple operations at the molecular level · Navneet Kaur Subodh Kumar · More Details Abstract Fulltext PDF.

Wide-field time-resolved luminescence imaging and spectroscopy to decipher obliterated documents in forensic science

Science.gov (United States)

Suzuki, Mototsugu; Akiba, Norimitsu; Kurosawa, Kenji; Kuroki, Kenro; Akao, Yoshinori; Higashikawa, Yoshiyasu

2016-01-01

We applied a wide-field time-resolved luminescence (TRL) method with a pulsed laser and a gated intensified charge coupled device (ICCD) for deciphering obliterated documents for use in forensic science. The TRL method can nondestructively measure the dynamics of luminescence, including fluorescence and phosphorescence lifetimes, which prove to be useful parameters for image detection. First, we measured the TRL spectra of four brands of black porous-tip pen inks on paper to estimate their luminescence lifetimes. Next, we acquired the TRL images of 12 obliterated documents at various delay times and gate times of the ICCD. The obliterated contents were revealed in the TRL images because of the difference in the luminescence lifetimes of the inks. This method requires no pretreatment, is nondestructive, and has the advantage of wide-field imaging, which makes it is easy to control the gate timing. This demonstration proves that TRL imaging and spectroscopy are powerful tools for forensic document examination.

Laser spectroscopy and its applications

International Nuclear Information System (INIS)

Radziemski, L.J.; Solarz, R.W.; Paisner, J.A.

1987-01-01

Laser spectroscopy has applications in diverse fields ranging from combustion studies and trace-sample detection to biological research. At the same time, it has also contributed greatly to the discovery of hundreds of new lasers. This symbiotic relationship has promoted an especially rapid expansion of the field. This book provides a review of the subject. It includes, for example, chapters on laser isotope separation techniques, enabling scientists to compare their relative advantages and drawbacks. This volume also gives numerous tables that summarize important features of lasers, experiments, and parameters for quick reference. In addition, it presents diagrams for visualizing rotational molecular energy levels of high J in order to enhance our understanding of molecular motions and their relationship to molecular energy levels. Offering insights into how experts think this technology will improve, it considers research and development in each topic discussed