Shavkat Sh. Nabiev

Spectroscopic exhibitions of structural nonrigidity in simple and complex molecular systems

The results of experimental and theoretical studies of the influence of large amplitude motions of nuclei on the IR and Raman spectra, electrooptical parameters, and structural features of molecular systems in various stages of aggregation are generalized. The mechanisms of intramolecular rearrangements in these systems are considered. The potential of the finite element method for the description of the large amplitude motions of arbitrary form is demonstrated. A method for estimation of the characteristic time of intramolecular rearrangements is proposed.

Vibrational spectroscopy of xenon and krypton fluorides in non-aqueous solvents and liquid noble gas solutions

concentration causes the slight decrease of 596 cm1band intensity and at concentration of 8x104 mole/ithis band intensity is practically independent on XeF6concentration in liquid Xe. Such behaviour of 596cm1 band intensity is connected with XeF6 transitionfrom monomeric phase at low concentration which ischaracterised by 596 and 516 cm1 bands to polymeric

Research of infrared spectra of PH3 molecule dissolved in liquefied argon

The aim of this work is to study IR spectra of phosphine solutions in liquid argon at 94 - 96 K within the range of 5700 - 500 cm -1 . Special attention has been paid to the spectra analysis in an insufficiently known area of combination modes and overtones, the determination of integral absorption coefficients of corresponding transitions, spectral windows as well as phosphine solubility in liquid argon, which according to our data makes 2 X 10 -3 mole fraction.

Current Trends in the Development of Remote Methods of Detecting Radioactive and Highly Toxic Substances

The chapter reviews the physical principles of active and passive methods of remote detection of radioactive substances and toxic agents in the atmosphere. It also reviews methods of measuring the parameters of regular and/or emergency gas-aerosol emissions and clusters of radioactive and poisoning fragments and microparticles on various surfaces, which provide the means of solving a range of problems unique to environmental monitoring.

Terahertz spectroscopy of heavy and superheavy water vapors

The paper reports on preliminary results of a study into a possibility of developing a fast method of atmospheric air analysis for the purpose of determination of the isotope composition of water vapors (H<inf>2</inf>¹⁸O, HD¹⁶O, HTO) with the method of non-stationary terahertz (THz) range spectroscopy.

Spectroscopic exhibitions of large-amplitude motions in halogen-containing coordination systems

The spectroscopic exhibitions of the structural non-rigidity effects in the series of the complex molecular systems with a few large amplitude motions are investigated with the application of the combination of original experimental and theoretical approaches which were tested by us earlier for the study of the floppy molecules. The characteristic times of intramolecular rearrangements are estimated for the fluorocontaining compounds having the most structural non- rigidity among the R2NPX2 (R equals Me, Et; X equals F, Cl, Br) systems. Using ab initio calculations of the potential energy surfaces, the tendency of the MeOPX2 (X equals F, Cl) molecules is revealed with respect to two kinds of the large amplitude motions. They are internal rotations of the CH3 group around the C-O bond and rotations of the CH3 and PX2 groups relative to the P-O bond. On the basis of the nonempirical dynamic calculations, the features of the vibrational spectrum of the MeSiF3 molecule are studied for the region of the torsion vibrations of the CH3 and SiF3 groups around the C- Si bond.

IR spectroscopy of interhalides XF3 and XF5 (X = Cl, Br)

Interhalogens XF3 and XF5 (X equals Cl,Br) are widely used for reprocessing of nuclear materials, in electronic and iron-and-steel industries. At the same time XF3 and XF5 may be regarded among most dangerous components in the plumes of emergency ejections of these manufactures. The Cl and Br fluorides interact actively with atmospheric gases resulting in the formation of hydrogen halogen, Cl and Br oxyfluorides and oxides which are transformed into stable complexes (HHal)x...(H2O)y, where Hal equals F, Cl, Br; x + y >= 2. A study into reaction mechanisms with a participation of the XF3 and XF5 compounds, their secondary compounds and the applicability of the remote laser control techniques requires comprehensive information on vibration spectra of interhalogens.

IR cryospectroscopy of fluoride molecules in noble gas liquid solutions

The main peculiarity of liquefied noble gases is their high inertia and transparency in the region from the far ultraviolet to the far infrared. Therefore, a cryospectroscopic technique may be employed not only for determination of basic molecular parameters (vibrational frequencies, isotopic shifts, etc.) but also for the studying of chemically aggressive and unsteady compounds, for investigation of molecular systems produced as a result of complex formation and photochemical reaction, for the determination of a small quantity of impurity in gases (approximately equals 10-4 - 10-7%), and for obtaining information concerning molecular of solute dynamics, etc.

SubTHz and FTIR spectroscopy of explosive vapors

Discussed are experimental results of subTHz vapor phase spectroscopy over solid samples of explosives, such as commercial trinitrotoluene (THT), nitroglycerine (NG) and cyclonite (RDX). The as-obtained results were compared against analyses results of the natural decomposition products of some explosives with the use of the Fourier-transform IR-spectrometry.

Anomalies in vibrational spectra of hydrides of the VA group elements in the condensed state

The results of a study of vibrational spectra of volatile hydrides of the VA group elements of periods 2 - 4 in the liquid state and in solutions of liquefied noble gases have been generalized and analyzed over wide frequency and temperature ranges. A number of anomalies have been revealed in the spectra of these hydrides that manifest themselves through an unusual behavior of band intensities of basic, composite vibrations and overtones on a transition from the gas phase to the condensed state, and dependences of spectroscopic and dynamic parameters as well as a non- coincidence of the line maxima in isotropic and anisotropic Raman spectra ((delta) v equals vaniso-viso) on the temperature of liquid hydrides. Mechanisms of intermolecular interactions in these liquids are discussed with the use of the as-obtained data on the intensity, frequency and shape of vibrational band contours.