Molecular Spectroscopy

Composition of the prehistoric pigments' (from Carriqueo rock shelter, Rio Negro province, Argentina) has been analysed by means of molecular spectroscopy (Fourier transform infrared (FTIR) and micro-Raman) and scanning electron microscopy (SEM) coupled to an energy-dispersive X-ray spectrometer (EDS). Red and yellow pigments were recognized as red and yellow ochre. The matrix of the pigments is composed of one or more substances. According to the matrix composition yellow and red pigments were also divided into two groups-i.e. those containing kaolinite or sulphates. Green pigment was detected as green earth, made up of celadonite as a chromophore.

During exhumation of the Brooks Range internal zone, amphibolite-facies rocks were emplaced atop the blueschist/greenschist facies schist belt. The resultant inverted metamorphic field gradient is mappable as a series of isograds encountered as one traverses up structural section. Amphibolite-facies metamorphism occurred at ~ 110 Ma as determined from 4°Ar/39Ar analysis of hornblende. This contrasts with 4°Ar/39Ar phengite cooling ages from the underlying schist belt, which are clearly older (by 17-22 m.y.). Fabrics in both the amphibolite-facies rocks and schist belt are characterized by repeated cycles ofN-vergent crenulation and transposition that was likely associated with out-of-sequence ductile thrusting in the internal zone of the Brooks Range orogen. Contractional deformation occurred in an overall environment of foreland-directed tectonic transport, broadly synchronous with exhumation of the internal zone, and shortening within the thin-skinned fold and thrust belt. These data are inconsistent with a recently postulated mid-Cretaceous episode of lithospheric extension in northern Alaska.

The present investigation is insightful in discerning the experimental and
computational spectroscopic behavior of 2-(4-methoxystyryl)-4,6-bis(trichloromethyl)-
1,3,5 triazine (MSTCMT) by employing density functional theory
(DFT) at B3LYP/6–311þþG(d,p)/cc-pVDZ basis sets. The detailed
vibrational analysis has been carried out using FT-IR and Raman within
3500–400 cm−1 and 3500–600cm−1 respectively assisted by VEDA.
Chemical shifts obtained from nuclear magnetic resonance (NMR) provided
essential information useful in analyzing the molecular structure of
MSTCMT. The thermodynamic functions of the MSTCMT molecule have
been calculated at 298.15 K using the B3LYP method at 6–311þþG(d,p)
and cc-pVDZ basis sets. The non-linear optical properties such as polarizability,
first-order hyperpolarizability, and second-order hyperpolarizability
of the MSTCMT molecule have been calculated using 6–311þþG(d,p) and
cc-pVDZ basis set at B3LYP level. Molecular docking has been performed
to check the inhibitory effect of MSTCMT against the SARS-CoV-2 receptors.

The visible electronic transitions of NiH have been recorded with rotational resolution by intracavity laser absorption spectroscopy. The gas phase NiH molecules were produced in an electric discharge using a nickel cathode and a trace amount of hydrogen with approx. 1 torr argon. Results of the analysis will be presented.

We present a Doppler-limited transmission spectrum of the rubidium dimer, suitable for frequency calibration of near infrared (e.g. Ti:sapphire) excitation experiments in the region 9500-12 300 cm À1 . It provides an abundant source of reference peaks that can be used in a graphic environment to calibrate short (<1 cm À1 ) scans of excitation spectrum. This is a sequel to an iodine atlas in ascii format [1] that we routinely use for the same purpose in the visible spectrum. The rubidium spectrum was recorded at an instrumental resolution of 0.018 cm À1 . Absolute precision is expected to be $0.005 cm À1 , and relative precision $0.003 cm À1 . The Rb 2 A-X transmission spectrum is available in ascii format, as supplementary material.

Absorption cross-sections for the 5th (6 ← 0) and 6th (7 ← 0) OH overtones for gas-phase methanol, ethanol, and isopropanol were measured using a slow flow cell and Incoherent Broadband Cavity-Enhanced Absorption Spectroscopy (IBBCEAS). Measurements were performed in two wavelength regions, 447–457 nm, and 508–518 nm, using two different instruments. The experimental results are consistent with previous computational predictions of the excitation energies for these transitions. Treating the OH stretch as a local mode allowed for calculation of the fundamental vibrational frequency (ωe), anharmonicity constant (ωexe), and the vertical dissociation energy (VDE) for each alcohol studied. The fundamental vibrational frequency is 3848 ± 18 cm􀀀 1, 3807 ± 55 cm􀀀 1, and 3813 ± 63 cm􀀀 1 for methanol, ethanol, and isopropanol, respectively. The anharmonicity constant was measured to be 84.8 ± 2.1 cm􀀀 1, 80.2 ± 5.9 cm􀀀 1, and 84.4 ± 6.8 cm􀀀 1 for methanol, ethanol, and isopropanol, respectively. The OH vertical dissociation energy was measured to be 499.4 ± 18.4 kJ/mol, 518.0 ± 56.7 kJ/mol, and 492.7 ± 59.9 kJ/mol. The spectroscopically measured values are compared to thermodynamically measured OH bond dissociation energies. The observed differences in previous measurements of the bond dissociation energies compared to the values reported herein can be explained due to the difference between vertical dissociation energies and bond dissociation energies. If the OH overtone stretching mode is excited in methanol to either the 5th or 6th overtone, the bimolecular reaction between methanol and O2 becomes thermodynamically feasible and could contribute to formation of methoxy and HO2 radical under the proper combination of pressure and temperature.

We present a new distance estimation method for dust-continuum-identified molecular cloud clumps. Recent (sub-)millimeter Galactic plane surveys have cataloged tens of thousands of these objects, plausible precursors to stellar clusters, but detailed study of their physical properties requires robust distance determinations. We derive Bayesian distance probability density functions (DPDFs) for 770 objects from the Bolocam Galactic Plane Survey in the Galactic longitude range 7. • 5 ≤ ℓ ≤ 65 • . The DPDF formalism is based on kinematic distances, and uses any number of external data sets to place prior distance probabilities to resolve the kinematic distance ambiguity (KDA) for objects in the inner Galaxy. We present here priors related to the mid-infrared absorption of dust in dense molecular regions and the distribution of molecular gas in the Galactic disk. By assuming a numerical model of Galactic mid-infrared emission and simple radiative transfer, we match the morphology of (sub-)millimeter thermal dust emission with mid-infrared absorption to compute a prior DPDF for distance discrimination. Selecting objects first from (sub-)millimeter source catalogs avoids a bias towards the darkest infrared dark clouds (IRDCs) and extends the range of heliocentric distance probed by mid-infrared extinction and includes lower-contrast sources. We derive well-constrained KDA resolutions for 618 molecular cloud clumps, with approximately 15% placed at or beyond the tangent distance. Objects with mid-infrared contrast sufficient to be cataloged as IRDCs are generally placed at the near kinematic distance. Distance comparisons with Galactic Ring Survey KDA resolutions yield a 92% agreement. A face-on view of the Milky Way using resolved distances reveals sections of the Sagittarius and Scutum-Centaurus Arms. This KDA-resolution method for large catalogs of sources through the combination of (sub-)millimeter and mid-infrared observations of molecular cloud clumps is generally applicable to other dust-continuum Galactic plane surveys.

A broadband chirped-pulse Fourier transform mm-wave spectrometer operating in the 260-290 GHz frequency range has been constructed. The spectrometer uses a dual channel arbitrary waveform generator to create both the chirped excitation pulse and local oscillator (LO) inputs to the mm-wave multiplier chains for excitation (x24) and detection in a sub-harmonic mixer. The excitation and LO pulses are derived from the same single frequency phase-locked microwave oscillator giving good phase stability to permit deep averages of the molecule free induction decay signals. The excitation chirp from 2 to 3.5 GHz is generated by a high-speed arbitrary waveform generator and provides direct access to the full bandwidth of the spectrometer. All frequency sources in the experiment are locked to a 10 MHz Rb-disciplined oscillator providing direct frequency calibration for molecular transitions in the Fourier transform frequency-domain spectrum. Benchmark measurements on methylamine, ethyl cyanide...

In this age of modern era, the use of internet must be maximized. Yeah, internet will help us very much not only for important thing but also for daily activities. Many people now, from any level can use internet. The sources of internet connection can also be enjoyed in many places. As one of the benefits is to get the on-line atomic and molecular spectroscopy basic aspects and practical applications book, as the world window, as many people suggest.

Ah initio calculations, using a minimal basis set and all possible valence configurations, have been performed on NS, SiF, and Ccl, at internuclear distances between 2.4 and 6 hohr. New bound states are predicted for all molecules, and approximate spectroscopic constants are given. Observed states of *Z+ and 2A symmetry which are not calculated to he bound are identified as nonvalence states. The inclusion of Rydberg or polarization orbitals for a proper description of these states is suggested. et 01. ( ) forms the basis of our discussions. Accordingly, besides the X211 ground state, the excited valence states R211, 112A, G?Z-, H*& and IZ+ (in order of increasing T,) have been definitely identified, in addition to the C2Z+ Rydberg state. Furthermore, a lowlying 2S+ state has recently been reported (9) and has been named the B state in analogy to the R state of PO. However, in order to avoid confusion, the label B will be reserved for the B211 state of NS. Indirect evidence derived from various perturbations suggests the existence of 4TI, 45-, and % states (dotted lines in Fig. ).

Potential energy curves were calculated for the ground state of PN and for all excited singlet and triplet states resulting from the 2a -37r. 70 -3~. 2a -8~. and 7a -80 orbital excitations. CI studies at 4 A served to establish dissociation energies. Spectroscopic constants were calculated, and are in good agreement with those ofthe known X'Z' and A'II states. Overall, their similarity with those observed for N2 is striking. Various states considered to perturb the known excitations are discussed. The recently discovered second 'Z+ state is included.

Some art objects being small and very precious prevents conservators and conservation scientists from whatever kind of sampling, so that only completely non-invasive (n.i.) studies are permitted. Besides, also moving the object is sometimes forbidden: this happens for jewels as well as for manuscripts, illuminated codices, drawings and paintings. Some important physical n.i. analyses, such as PIXE and PIGE, therefore cannot be used in many cases. With these limitations, only imaging techniques in X, UV, Visible and IR bands, and a few spectroscopic methods that can be carried out with portable instruments can be applied, i.e. molecular spectroscopies like Fourier transform infrared (FTIR), Raman, UV visible and near IR reflectance spectrometry (UV-Vis-NIR RS) and atomic spectroscopy like energy dispersive X-ray fluorescence (EDXRF). The use of only one or two of these techniques is usually far from giving all the information required to achieve a full characterization of materials used by the artist or during restorations, and to understand some conservative problems of the object. On the contrary, a joined use of n.i. analyses can supply a larger set of data, allowing for cross checks. With this aim we show a fully integrated spectroscopic approach to polychrome objects, and, in particular, to drawings and illuminated manuscripts, using portable instruments, specifically µ-FTIR, µ-Raman, Vis-RS and EDXRF, where also the Raman signal does not suffer fluorescence caused by varnish coating and from binder. We propose the joined use of all these four physical analyses to characterize materials -support, pigments, dyes, binders, etc. -on a complex case: a painted and drawn parchment of the late 15th century, or the beginning of the 16th, partly attributed to Andrea Mantegna. The collected spectroscopic data have been compared to proper spectral databases, some of which specifically realized in our laboratories. Also, mixtures of pigments and their stratigraphical sequence have been detected, as well as important data related to the manufacturing and the type of iron-gall ink.

The rovibrational spectrum of the v 14 CH 3 -bending mode of dimethyl sulfide CH 3 SCH 3 was recorded in the 945-1005 cm À1 spectral region combining data from a tunable infrared quantum cascade laser spectrometer coupled to a pulsed slit jet and from a high resolution Fourier transform spectrometer coupled to a room temperature gas absorption cell. The characteristic PQR band contour of a vibrational mode with a b 1 symmetry species in the C 2v group was observed with both infrared methods but the rovibrational cooling achieved in the pulsed supersonic expansion (20 K in rotation) proved to be essential for starting the rovibrational analysis of such asymmetric top molecule. Internal rotation splittings were recently observed and analyzed in the ground and first torsional excited states. However, they are expected to be very small and could not be resolved in the v 14 state using our infrared spectroscopic probes. Therefore a classic reduced effective Hamiltonian of an asymmetric rigid rotor was used. Finally, 1119 transitions from both jet-cooled and room temperature experiments were assigned and included in a global fit with J 29. A total of 9 rovibrational parameters including pure rotational constants as well as quartic centrifugal distortion constants were determined with high accuracy. These parameters can be used to produce a reliable line-list for an atmospheric detection of DMS.

The rotational spectra of the normal and N-D isotopic species of pyrrolidine have been measured. The molecule exists in an envelope conformation, with the nitrogen atom out of the plane containing the carbon atoms and with the imino hydrogen in the axial position. The analysis of the rotational spectra of two and three vibrationally excited states for the normal and N-D isotopic species, respectively, indicates that both barriers to pseudorotation and to the imino hydrogen inversion are relatively high. Additionally, the N( ) quadrupole coupling constants have been determined. I The terms "twist" or "half-chair" (sometimes "chair") and "bent" or "envelope" are equally found in literature.

The microwave spectrum of normal thiomorpholine (CH,-CH,-S-CH,-CH,-NH) was investigated within the region 8-40 GHz, and that of N-deuterothiomorpholine (CH,-CH,-S-CH,-CH,-ND) within the region 26.5-40 GHz. The observed spectra are due to the chair equatorial conformers. The rotational constants of both isotopic species were determined for the ground states and for two vibrationally excited states. The dipole moment components and quadrupole coupling constants of normal thiomorpholine and the iminohydrogen rs coordinates were also determined.

With respect to specious application of phenyl hydrazine and its derivative in organic Chemistry, Pharmacy and chemical industry. On its toxicity and biological effects, the 2-[Phenyl -(Phenyl Hydrazino) -Methyl] Phenyl amine are raised from interaction between 2-phenyl hydrazine and ceton in acid media. The constitution of this ligand is described below: presence of acetonitrile solvent in spectrophotometry the temperature is 25 o C method using SHIMADZU 2550 devise a complex constitution is observed by strewing Cu 2+ the cation by a 10 microlitric syringe on a solvent made in a quartz cell (1cm), (that ligand with concentration of 5.8×10 -4 ). This observation was using the molar proportions. for more confidence they used other ways such as jab method with stochiometric 1:1 and spectrum method FT-IR, FT-NMR that the devices names called SHIMADZU IR470, BRUKER 200 MHZ.

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Some 39 lines in the B Werner band of the D 2 molecule were measured using a narrowband tunable extreme-ultraviolet laser source, at an unprecedented accuracy of Á= ¼ 6 Â 10 À8 . The results bear relevance for future use in the calibration of dense classical spectra obtained for the HD and D 2 hydrogen isotopologues.

Two laser spectroscopic investigations were performed on the C 1 S / -X 1 S / (1,0) and (0,0) bands of CO. In the first experiment, using 2 / 1 resonance-enhanced multiphoton ionization, information on highly excited rotational states up to J É 50 was obtained. In the second experiment, application of a narrow-band VUV laser provided highly accurate absolute calibrations. Molecular constants for 12 C 16 O, 13 C 16 O, 12 C 18 O, and, for the first time, 12 C 17 O are derived.

The combination of high resolution laser spectroscopy in collimated cold molecular beams with mass selective detection allows investigations of rotationally resolved molecular spectra of selected molecular species in the presence of molecules with overlapping absorption spectra. This is illustrated by some examples, such as the isotope selective spectroscopy of Ag2-dimers or the sub-Doppler spectroscopy of Na3 in supersonic beam with a broad mass distribution of different clusters. Time resolved laser spectroscopy of excited states of alkali molecules, perturbed by bound dark states or by repulsive states, yields information about singlet-triplet mixing and predissociation rates.

Arcavacata di Rende (Cosenza), Italy Selection rules on the rotational structure of doublet-quartet transitions in asymmetric top molecules are discussed on the basis of the spin-orbit coupling mechanism, rather than by symmetry arguments, and some additional rules are found with respect to a previous work. In the case that the combining doublet and quartet states are appreciably mixed only with levels directly connected to them by the spin-orbit operator, it turns out that, except for the very low values of the rotational quantum numbers, branches with IAN -AJ I> 1 are essentially forbidden. Thus, branches with AN = f 3 (T and N branches) are not expected to be observable. In this case, it is found also that in a high magnetic field transitions with AMs = f 2 are forbidden, and only AMs = 0, fl bands are expected to occur. All these restrictions are removed if the combining states are also appreciably contaminated by states indirectly connected to them by the spin-orbit operator, through intermediate levels. This rule is not exact, but in the case of weak spin-orbit coupling it can appreciably break down only for the very low values of the rotational quantum numbers. It also forbids transitions with AN = f 3, that is the T and N branches which are generally 175

We discuss a symmetry-adapted algebraic (or vibron) model for molecular spectroscopy. The model is formulated in terms of tensor operators under the molecular point group. In this way, we have identified interactions that are absent in previous versions of the vibron model, in which the Hamiltonian is expressed in terms of Casimir operators and their products. The inclusion of these new interactions leads to reliable spectroscopic predictions. As an example we study the vibrational excitations of the methane molecule, and compare our results with those obtained in other algebraic models.

The vibrational excitations of ozone, including both bending and stretching vibrations, are studied in the framework of a symmetry-adapted algebraic approach. This method is based on the isomorphism between the U (2) algebra and the one-dimensional Morse oscillator, and the introduction of point group symmetry techniques. The use of symmetry-adapted interactions, which in the harmonic limit have a clear physical interpretation, makes it possible to systematically include higher order terms and anharmonicities. A least-square fit to all published experimental levels (up to ten quanta) of 16 O 3 and 18 O 3 yields a r.m.s. deviation of 2.5 and 1.0 cm -1 , respectively.

We introduce the Anharmonic Oscillator Symmetry Model to describe vibrational excitations in molecular systems exhibiting high degree of symmetry. A systematic procedure is proposed to establish the relation between the algebraic and configuration space formulations, leading to new interactions in the algebraic model. This approach incorporates the full power of group theoretical techniques and provides reliable spectroscopic predictions. We illustrate the method for the case of D 3h -triatomic molecules.

We apply the Anharmonic Oscillator Symmetry Model to the description of vibrational excitations in D 3h and T d molecules. A systematic procedure can be used to establish the relation between the algebraic and configuration space formulations, by means of which new interactions are found in the algebraic model, leading to reliable spectroscopic predictions. We illustrate the method for the case of D 3h -triatomic molecules and the T d Be-cluster.

The ingredients of the quantum theory of orbital and spin angular momentum encounter continuing relevance in wide areas beyond the traditional ones (molecular, atomic and nuclear spectroscopies and dynamics). This paper offers a presentation of the connection at the most elementary of levels with the diagrammatic approaches to projective geometry. In particular here we exhibit how the Fano, Desargues and related incidence configurations emerge in the Racah and in the Biedenharn-Elliott identities, corresponding respectively to the hexagonal and pentagonal relationships that provide the basis for the construction of 3nj symbols and of spin networks. It is shown that the treatment, although mostly confined to the quadrangulation of the real projective plane, permits however the introduction of networks involving seven and ten spins, and preludes to developments towards computational and asymptotic approaches for quantum and semi-classical applications.

The ingredients of the quantum theory of orbital and spin angular momentum encounter continuing relevance in wide areas beyond the traditional ones (molecular, atomic and nuclear spectroscopies and dynamics). This paper offers a presentation of the connection at the most elementary of levels with the diagrammatic approaches to projective geometry. In particular here we exhibit how the Fano, Desargues and related incidence configurations emerge in the Racah and in the Biedenharn-Elliott identities, corresponding respectively to the hexagonal and pentagonal relationships that provide the basis for the construction of 3nj symbols and of spin networks. It is shown that the treatment, although mostly confined to the quadrangulation of the real projective plane, permits however the introduction of networks involving seven and ten spins, and preludes to developments towards computational and asymptotic approaches for quantum and semi-classical applications.

We have applied Lie algebraic model to distorted structure molecules to determine the vibrational spectra of dierent stretching and bending vibrational modes. The the Lie algebraic model of the Hamiltonian expression is By using the Lie algebraic method, the stretching vibrational energies of fullerene (C80) are calculated in the one-dimensional [U(2)] framework. Using the model Hamiltonian so constructed, we have calculated the local mode vibrational energy levels of the fullerene (C80) accurately.

A variety of laser spectroscopic methods are employed in this thesis research for studies of CF3NO, an interesting model photodissociative system, and for investigation of low energy rotations and vibrations of small molecules and low molecular weight clusters in free jet expansions. Nonradiative energy decay for electronically excited CF3NO is investigated in an argon matrix. By comparing the visible absorption spectrum with pulsed laser photoacoustic and fluorescence excitation spectra it is argued that all nonradiative decay processes are fast, thus eliminating the likelihood of transient separation of CF3 and NO photofragments in the matrix cage or appreciable decay through a low lying triplet state. No evidence is found for a "channel two" decay mechanism in the matrix in contrast to gas phase work of others. Upper state vibrational relaxation is seen to be exceedingly fast by From his excellent example I have managed to learn a little about the value of careful, patient, and persistent work. His enthusiasm, optimism and willingness to attempt new or difficult projects have managed, with time, to even temper my own conservative nature. I would like to thank the technical staff in the chemistry department for their vital support during my work at Oregon State University. These people include John Archibald, Robert Boyer, Gerald Allison, and Doyle Woodrow without whom this research would never have been taken to completion. A number of other people have assisted me greatly in the lab, most notably Nancy Triggs, Steven Bares, George Pubanz, and Jeng Yang. I am indebted to each of them for their generous participation. Finally my heartfelt thanks goes out to my wife, Sena, and our children, Mary, Jessica and Bridget, for their patience and support during the many years I spent obtaining both my undergraduate and graduate degrees. TABLE OF CONTENTS CHAPTER 1 INTRODUCTION The use of lasers in chemical physics CF3NO Spectroscopy and Photophysics CHAPTER 2 4 PHOTOACOUSTIC SPECTROSCOPY AND ENERGY RELAXATION IN MATRIX Jet Expansion into a Finite Background Pressure 92

A variety of laser spectroscopic methods are employed in this thesis research for studies of CF3NO, an interesting model photodissociative system, and for investigation of low energy rotations and vibrations of small molecules and low molecular weight clusters in free jet expansions. Nonradiative energy decay for electronically excited CF3NO is investigated in an argon matrix. By comparing the visible absorption spectrum with pulsed laser photoacoustic and fluorescence excitation spectra it is argued that all nonradiative decay processes are fast, thus eliminating the likelihood of transient separation of CF3 and NO photofragments in the matrix cage or appreciable decay through a low lying triplet state. No evidence is found for a "channel two" decay mechanism in the matrix in contrast to gas phase work of others. Upper state vibrational relaxation is seen to be exceedingly fast by From his excellent example I have managed to learn a little about the value of careful, patient, and persistent work. His enthusiasm, optimism and willingness to attempt new or difficult projects have managed, with time, to even temper my own conservative nature. I would like to thank the technical staff in the chemistry department for their vital support during my work at Oregon State University. These people include John Archibald, Robert Boyer, Gerald Allison, and Doyle Woodrow without whom this research would never have been taken to completion. A number of other people have assisted me greatly in the lab, most notably Nancy Triggs, Steven Bares, George Pubanz, and Jeng Yang. I am indebted to each of them for their generous participation. Finally my heartfelt thanks goes out to my wife, Sena, and our children, Mary, Jessica and Bridget, for their patience and support during the many years I spent obtaining both my undergraduate and graduate degrees. TABLE OF CONTENTS CHAPTER 1 INTRODUCTION The use of lasers in chemical physics CF3NO Spectroscopy and Photophysics CHAPTER 2 4 PHOTOACOUSTIC SPECTROSCOPY AND ENERGY RELAXATION IN MATRIX Jet Expansion into a Finite Background Pressure 92

Many important molecules show strong characteristic vibrational transitions in the mid-infrared (MIR) part of the electromagnetic spectrum. This leads to applications in spectroscopy, chemical and bio-molecular sensing, security and industry, especially over the mid-and long-wave infrared atmospheric transmission windows of 3-5 μm and 8-13 μm. In this paper, we review some of our more recent experimental and simulation work aimed at developing new light sources based on chalcogenide glass optical fibres that can help us utilize this spectral region for biomedical applications. This includes the development of supercontinuum and bright luminescent sources and our progress towards fibre-based lasers. We place these developments in the context of MIR imaging and spectroscopy in order to show how they bring the promise a new era in healthcare and clinical diagnostics.

A method for quantitative analysis of multicomponent mixtures with unknown individual spectra of the components, based on resolution of overlapping bands, is developed and its reliability is illustrated in analysis of both model and real mixtures. The two -step optimization procedure allows 1 Dedicated to our memorable teacher and colleague Assoc. Prof. Dr. V.Dyakovitch, who died in 1995. 2 Author for the correspondence. ANTONOV AND NEDELTCHEVA 2056 attainment of high precision, the molar parts and the individual spectra of the components. This approach could be used in molecular spectroscopy (UV-Vis-NIR, IR, Raman and CD spectroscopy) as well as in chromatography.

Herewith we present the results of our studies on the dynamics of acetone/methanol binary mixtures by means of molecular dynamics simulations and femtosecond optical Kerr effect (OKE) spectroscopy. The OKE response exhibits the apparent dependence on a mole fraction of the mixture components, and thus carries the information about the influence of its composition on the intermolecular interactions and momentary local structures. The molecular dynamics simulations, which take into account the reorientational dynamics of the molecules, have been performed in order to explain the concentration dependence of the long time part of the experimental OKE response.

V. Mozhayskiy, M. N. Slipchenko, V. K. Adamchuck and A. F. Vilesov J. Chem. Phys.M. N. Slipchenko, B. G. Sartakov and A. F. Vilesov J. Chem. Phys.D. Skvortsov, M. Y. Choi and A. F. Vilesov J. Phys. Chem. AK. E. Kuyanov, M. N. Slipchenko, B. Khalajestani, R. Sliter, and A. F. Vilesov 62th International Symposium on Molecular Spectroscopy

 With the modified Robert-Bonamy (RB) formalism, the halfwidth  is given by The integrand of  is  Usually, S 2 consists of three terms S 2,outer,I , S 2,outer,f , and S 2,middle . For example, S 2,outer,I is given by  In order to consider more realistic potentials, it is necessary to include a short range atom-atom model V atom-atom (t) () 2 2 2 2 2 2 Re ( ) (1 ).