E. Chesnokov - Academia.edu (original) (raw)
Papers by E. Chesnokov
Theoretical and Experimental Chemistry
ABSTRACT The vibrational relaxation rates of Sill 4 were measured by laser-induced IR luminescenc... more ABSTRACT The vibrational relaxation rates of Sill 4 were measured by laser-induced IR luminescence. A CO 2 laser with modulated quality was used for the excitation. The laser Was tuned to the line P(20) 10.6 #m, which has the highest absorption coefficient in Sill 4. The pulse energy was ~1 mJ, the duration was less than 1 psec, and the recurrence frequency was ~150 Hz. The IE luminescence was recorded in a direction perpendicular to the laser beam by means of a Ge-Au photoresistor. The signal-to-noise ratio was usually less than 1; thus, signal accumulation in the memory of a digital multichannel storing device was used. The number of accumulations was 104-105, which took 1-10 min. The stored signal was recorded on an X-Y recorder. A scheme of the vibration levels of SiHr is shown in Fig. 1. Of the four vibration modes, only two are active in the IR spectrum: v4=913 cm -1 and v3=2190 cm -l. The laser excites the v 4 vibration. Excitation of the Sill 4 molecule produces luminescence in the region of 900 cm -i as well as in the region 2000 cm -i. The luminescence signal in the region 900 cm -i was several times weaker than in the region 2000 cm -1. Besides this, scattered laser radiation interferes with the observation of luminescence in the 900-cm -1 region. Thus, all measurements were carried out by observing the luminescence of v 3 vibration, whichwas isolated by means of a LiF filter. As an example, Fig. 2a shows the luminescence signal observed in pure Sill 4. The drop in luminescence intensity is due to V-T,R relaxation; the non-zero intensity of luminescence after cessation of V-T,R relaxation is due to heating of the gas. The intensity of the thermal radiance with respect to the intensity of luminescence must be determined by the ratio of the vibrational thermal capacity of the gaseous medium and the total thermal capacity [2]. ]In the case of Sill 4 the ratio of the vibrational to the total thermal capacity is ~0.3, which is less than the corresponding thermal radiance observed. This discrepancy is due to the fact that in the Sill 4 molecule the transfer of energy between the excited vibration mode v 4 and the mode v 3 is relatively slow, so that during the energy transfer between the modes a significant amount of energy manages to relax. If we
Theoretical and Experimental Chemistry
Optoelectronics, Instrumentation and Data Processing, 2009
This paper reports the results of experimental studies and calculations of components of a model ... more This paper reports the results of experimental studies and calculations of components of a model system for detection and imaging in the terahertz range, including a free-electron laser and devices for laser radiation diagnostics, film shields with absorbing coatings for intermediate thermal imaging, and prototype sensitive elements based on PbSnTe : In films.
Atmospheric and Oceanic Optics, 2015
Journal of Applied Spectroscopy, 1988
2014 39th International Conference on Infrared, Millimeter, and Terahertz waves (IRMMW-THz), 2014
The possibility of converting the chemical energy of the SiH4 chlorination reaction into laser ra... more The possibility of converting the chemical energy of the SiH4 chlorination reaction into laser radiation is investigated experimentally. A neodymium laser was used to initiate the SiH4 + Cl2 chain reaction and the energy transfer from the excited SiH3Cl product was used to excite a CO2 molecule. Amplification of the laser beam at the laser transition in the CO2 molecule is reported.
Reaction Kinetics and Catalysis Letters, 1975
ABSTRACT The ratio of the rate constants has been measured for the reaction of atomic chlorine wi... more ABSTRACT The ratio of the rate constants has been measured for the reaction of atomic chlorine with CH4 and CD4 within the temperature range 163–613 K. At low temperatures (163–300 K) the ratio is 2.2 exp (1180/RT). The pre-exponential factor of 2.2 agrees with that calculated by transition state theory. A deviation from this exponential expression is observed as the temperature increases, which can also be explained by the transition state theory.
Reaction Kinetics and Catalysis Letters, 1976
The influence of non-equilibrium vibrational excitation of CH3F molecules on the rate of their re... more The influence of non-equilibrium vibrational excitation of CH3F molecules on the rate of their reaction with bromine atoms has been investigated. A three-fold increace in the reaction rate has been registered at CH3F and Br2 pressures of 0.07 Torr and at 100°C. The increase is shown not to be associated with equilibrium thermal heating.
Reaction Kinetics and Catalysis Letters, 1981
ABSTRACT
Kinetics and Catalysis, 2010
... under the Action of a Pulse CO2 Laser PS Dement'ev, PV Koshlyakov, and EN Chesnokov ... more ... under the Action of a Pulse CO2 Laser PS Dement'ev, PV Koshlyakov, and EN Chesnokov Institute of Chemical Kinetics and Combustion, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia e mail: dementyev@kinetics.nsc.ru Received December 21, 2009 ...
Combustion, Explosion, and Shock Waves, 2012
The possibility of detecting OH radicals and stable paramagnetic NO species in flames using the e... more The possibility of detecting OH radicals and stable paramagnetic NO species in flames using the effect of rotation of the polarization plane of terahertz radiation (1-10 THz) in a magnetic field (Faraday effect) was experimentally demonstrated. Experimental data on detection of NO in a cell and OH radicals in an atmospheric-pressure H 2 /O 2 /N 2 flame using this method are given. The proposed method can be used to study highly scattering media which are opaque in the visible region, for example, dusty or sooty flames.
Applied Physics Letters, 2012
ABSTRACT Optical free induction decay (FID) in the region of 60-75 cm{sup -1} was detected using ... more ABSTRACT Optical free induction decay (FID) in the region of 60-75 cm{sup -1} was detected using 120 ps pulses of free electron laser. Signals were detected in real time using ultra-fast Schottky diode detectors. The oscillations corresponding to the splitting of absorption lines in deuterated water vapor ({Delta}f = 0.15 cm{sup -1}) and hydrogen bromide ({Delta}f = 0.02 cm{sup -1}) were detected. At high optical density, we observed the oscillations arising from 'top-hat' shape of absorption lines. Free induction decay signals could be detected in a single shot. This observation allowed obtaining a spectrum in one laser pulse, which facilitates studies of very fast processes.
Applied Physics B, 2006
Infrared multiphoton absorption and dissociation of vinyltrifluorosilane molecules under the acti... more Infrared multiphoton absorption and dissociation of vinyltrifluorosilane molecules under the action of pulsed TEA CO 2-laser were experimentally studied. The composition of the end dissociation products has been analyzed. Using quantum chemical calculations, we have identified the dissociation pathways that lead to the observed end products. Transition state geometries, enthalpies and activation energies for the dissociation pathways have been calculated. The dissociation channel ratio was determined under used experimental conditions. The silicon isotope selective infrared multiphoton dissociation has been performed at different wavelengths of the CO 2-laser radiation.
Applied Magnetic Resonance, 1998
The dangling bond defects were investigated in a-Si:H particles formed under silane thermal decom... more The dangling bond defects were investigated in a-Si:H particles formed under silane thermal decomposition in flow reactor. EPR together with hydrogen evolution method were used. The experimental results allowed us to conclude that there are two kinds of dangling bond defects in a-Si:H aerosol particles. The defects of the first kind are localized on the surface of interconnected microvoids and microchannels (surface dangling bonds) and those of the second kind are embedded in amorphous silicon network (volume dangling bonds). The thermal equilibration of dangling bonds and temperature dependence of equilibrium dangling bond concentration were investigated. It was found that at temperatures >400 K the dangling bond concentration N reversibly depends on sample temperature. The volume dangling bond concentration increases with temperature increasing (the effective activation energy of dangling bond formation U> 0), and the surface dangling bond concentration decreases with temperature increasing (U < 0). It has been found that EPR line is considerably asymmetric for samples with high hydrogen content and for low hydrogen content the EPR line is weakly asymmetric. A conclusion was drawn that the asymmetry degree depends on amorphous silicon lattice distortions. This conclusion has been confirmed by EPR spectra simulations.
Applied Physics B, 2009
Infrared multiphoton absorption and dissociation of 1,2-dichloroethyltrifluorosilane molecules un... more Infrared multiphoton absorption and dissociation of 1,2-dichloroethyltrifluorosilane molecules under the action of pulsed TEA CO 2 laser were experimentally studied. The composition of dissociation products was analyzed. The only products of dissociation have been found to be stable molecules: chloroethylene and trifluorochlorosilane. Dissociation proceeds via chlorine atom transfer from carbon to silicon. The silicon isotope-selective infrared multiphoton dissociation was performed at different wavelengths of the CO 2-laser radiation. High degrees of silicon isotope separation have been achieved.
The Journal of Physical Chemistry A, 1997
ABSTRACT The infrared multiphoton dissociation (IR MPD) of formic acid molecules (HCOOH → CO + H2... more ABSTRACT The infrared multiphoton dissociation (IR MPD) of formic acid molecules (HCOOH → CO + H2O) with free electron laser radiation in the 3 μm region (C−H stretch vibrational absorption band) and in the 6 μm region (CO stretch vibrational absorption band) has been achieved using the same laser. Results indicate that initial excitation of this dimer is more efficient for MPD then initial monomer excitation. Carbon isotope-selective MPD has been performed with an isotopic mixture, H12COOH + H13COOH (50% + 50%), at an irradiating wavelength of 5.56 μm. For this mixture, isotopic selectivity s = k12/k13 = 23 has been attained as a ratio of the rate constants of the H12COOH MPD and the H13COOH MPD, respectively. The isotopic selectivity for 13C in the naturally occurring mixture (1.1% of 13C-containing molecules) s = k13/k12 = 22 has been attained at an irradiating wavelength of 5.90 μm.
Doklady Physical Chemistry
The fabrication of high-purity monoisotope silicon has recently stimulated considerable interest ... more The fabrication of high-purity monoisotope silicon has recently stimulated considerable interest , which is caused by the possibility of preparing perfect single crystals of silicon, a basic material for use in microelectronics. The higher heat conduction of 28 Si single crystals compared to that of single crystals with a natural abundance of isotopes was found in [2, 3] and explained in . Recently, the idea of creating a quantum computer based on monoisotope 28 Si doped with 31 P at definite points has been suggested [5]. It is not ruled out that 29 Si possessing a magnetic nucleus can also be used for this purpose. Because of the rich possibilities offered by monoisotope 28 Si for both fundamental studies and advance technology, searching for organosilicon compounds suitable for separation of silicon isotopes is a currently central problem.
Theoretical and Experimental Chemistry
ABSTRACT The vibrational relaxation rates of Sill 4 were measured by laser-induced IR luminescenc... more ABSTRACT The vibrational relaxation rates of Sill 4 were measured by laser-induced IR luminescence. A CO 2 laser with modulated quality was used for the excitation. The laser Was tuned to the line P(20) 10.6 #m, which has the highest absorption coefficient in Sill 4. The pulse energy was ~1 mJ, the duration was less than 1 psec, and the recurrence frequency was ~150 Hz. The IE luminescence was recorded in a direction perpendicular to the laser beam by means of a Ge-Au photoresistor. The signal-to-noise ratio was usually less than 1; thus, signal accumulation in the memory of a digital multichannel storing device was used. The number of accumulations was 104-105, which took 1-10 min. The stored signal was recorded on an X-Y recorder. A scheme of the vibration levels of SiHr is shown in Fig. 1. Of the four vibration modes, only two are active in the IR spectrum: v4=913 cm -1 and v3=2190 cm -l. The laser excites the v 4 vibration. Excitation of the Sill 4 molecule produces luminescence in the region of 900 cm -i as well as in the region 2000 cm -i. The luminescence signal in the region 900 cm -i was several times weaker than in the region 2000 cm -1. Besides this, scattered laser radiation interferes with the observation of luminescence in the 900-cm -1 region. Thus, all measurements were carried out by observing the luminescence of v 3 vibration, whichwas isolated by means of a LiF filter. As an example, Fig. 2a shows the luminescence signal observed in pure Sill 4. The drop in luminescence intensity is due to V-T,R relaxation; the non-zero intensity of luminescence after cessation of V-T,R relaxation is due to heating of the gas. The intensity of the thermal radiance with respect to the intensity of luminescence must be determined by the ratio of the vibrational thermal capacity of the gaseous medium and the total thermal capacity [2]. ]In the case of Sill 4 the ratio of the vibrational to the total thermal capacity is ~0.3, which is less than the corresponding thermal radiance observed. This discrepancy is due to the fact that in the Sill 4 molecule the transfer of energy between the excited vibration mode v 4 and the mode v 3 is relatively slow, so that during the energy transfer between the modes a significant amount of energy manages to relax. If we
Theoretical and Experimental Chemistry
Optoelectronics, Instrumentation and Data Processing, 2009
This paper reports the results of experimental studies and calculations of components of a model ... more This paper reports the results of experimental studies and calculations of components of a model system for detection and imaging in the terahertz range, including a free-electron laser and devices for laser radiation diagnostics, film shields with absorbing coatings for intermediate thermal imaging, and prototype sensitive elements based on PbSnTe : In films.
Atmospheric and Oceanic Optics, 2015
Journal of Applied Spectroscopy, 1988
2014 39th International Conference on Infrared, Millimeter, and Terahertz waves (IRMMW-THz), 2014
The possibility of converting the chemical energy of the SiH4 chlorination reaction into laser ra... more The possibility of converting the chemical energy of the SiH4 chlorination reaction into laser radiation is investigated experimentally. A neodymium laser was used to initiate the SiH4 + Cl2 chain reaction and the energy transfer from the excited SiH3Cl product was used to excite a CO2 molecule. Amplification of the laser beam at the laser transition in the CO2 molecule is reported.
Reaction Kinetics and Catalysis Letters, 1975
ABSTRACT The ratio of the rate constants has been measured for the reaction of atomic chlorine wi... more ABSTRACT The ratio of the rate constants has been measured for the reaction of atomic chlorine with CH4 and CD4 within the temperature range 163–613 K. At low temperatures (163–300 K) the ratio is 2.2 exp (1180/RT). The pre-exponential factor of 2.2 agrees with that calculated by transition state theory. A deviation from this exponential expression is observed as the temperature increases, which can also be explained by the transition state theory.
Reaction Kinetics and Catalysis Letters, 1976
The influence of non-equilibrium vibrational excitation of CH3F molecules on the rate of their re... more The influence of non-equilibrium vibrational excitation of CH3F molecules on the rate of their reaction with bromine atoms has been investigated. A three-fold increace in the reaction rate has been registered at CH3F and Br2 pressures of 0.07 Torr and at 100°C. The increase is shown not to be associated with equilibrium thermal heating.
Reaction Kinetics and Catalysis Letters, 1981
ABSTRACT
Kinetics and Catalysis, 2010
... under the Action of a Pulse CO2 Laser PS Dement'ev, PV Koshlyakov, and EN Chesnokov ... more ... under the Action of a Pulse CO2 Laser PS Dement'ev, PV Koshlyakov, and EN Chesnokov Institute of Chemical Kinetics and Combustion, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia e mail: dementyev@kinetics.nsc.ru Received December 21, 2009 ...
Combustion, Explosion, and Shock Waves, 2012
The possibility of detecting OH radicals and stable paramagnetic NO species in flames using the e... more The possibility of detecting OH radicals and stable paramagnetic NO species in flames using the effect of rotation of the polarization plane of terahertz radiation (1-10 THz) in a magnetic field (Faraday effect) was experimentally demonstrated. Experimental data on detection of NO in a cell and OH radicals in an atmospheric-pressure H 2 /O 2 /N 2 flame using this method are given. The proposed method can be used to study highly scattering media which are opaque in the visible region, for example, dusty or sooty flames.
Applied Physics Letters, 2012
ABSTRACT Optical free induction decay (FID) in the region of 60-75 cm{sup -1} was detected using ... more ABSTRACT Optical free induction decay (FID) in the region of 60-75 cm{sup -1} was detected using 120 ps pulses of free electron laser. Signals were detected in real time using ultra-fast Schottky diode detectors. The oscillations corresponding to the splitting of absorption lines in deuterated water vapor ({Delta}f = 0.15 cm{sup -1}) and hydrogen bromide ({Delta}f = 0.02 cm{sup -1}) were detected. At high optical density, we observed the oscillations arising from 'top-hat' shape of absorption lines. Free induction decay signals could be detected in a single shot. This observation allowed obtaining a spectrum in one laser pulse, which facilitates studies of very fast processes.
Applied Physics B, 2006
Infrared multiphoton absorption and dissociation of vinyltrifluorosilane molecules under the acti... more Infrared multiphoton absorption and dissociation of vinyltrifluorosilane molecules under the action of pulsed TEA CO 2-laser were experimentally studied. The composition of the end dissociation products has been analyzed. Using quantum chemical calculations, we have identified the dissociation pathways that lead to the observed end products. Transition state geometries, enthalpies and activation energies for the dissociation pathways have been calculated. The dissociation channel ratio was determined under used experimental conditions. The silicon isotope selective infrared multiphoton dissociation has been performed at different wavelengths of the CO 2-laser radiation.
Applied Magnetic Resonance, 1998
The dangling bond defects were investigated in a-Si:H particles formed under silane thermal decom... more The dangling bond defects were investigated in a-Si:H particles formed under silane thermal decomposition in flow reactor. EPR together with hydrogen evolution method were used. The experimental results allowed us to conclude that there are two kinds of dangling bond defects in a-Si:H aerosol particles. The defects of the first kind are localized on the surface of interconnected microvoids and microchannels (surface dangling bonds) and those of the second kind are embedded in amorphous silicon network (volume dangling bonds). The thermal equilibration of dangling bonds and temperature dependence of equilibrium dangling bond concentration were investigated. It was found that at temperatures >400 K the dangling bond concentration N reversibly depends on sample temperature. The volume dangling bond concentration increases with temperature increasing (the effective activation energy of dangling bond formation U> 0), and the surface dangling bond concentration decreases with temperature increasing (U < 0). It has been found that EPR line is considerably asymmetric for samples with high hydrogen content and for low hydrogen content the EPR line is weakly asymmetric. A conclusion was drawn that the asymmetry degree depends on amorphous silicon lattice distortions. This conclusion has been confirmed by EPR spectra simulations.
Applied Physics B, 2009
Infrared multiphoton absorption and dissociation of 1,2-dichloroethyltrifluorosilane molecules un... more Infrared multiphoton absorption and dissociation of 1,2-dichloroethyltrifluorosilane molecules under the action of pulsed TEA CO 2 laser were experimentally studied. The composition of dissociation products was analyzed. The only products of dissociation have been found to be stable molecules: chloroethylene and trifluorochlorosilane. Dissociation proceeds via chlorine atom transfer from carbon to silicon. The silicon isotope-selective infrared multiphoton dissociation was performed at different wavelengths of the CO 2-laser radiation. High degrees of silicon isotope separation have been achieved.
The Journal of Physical Chemistry A, 1997
ABSTRACT The infrared multiphoton dissociation (IR MPD) of formic acid molecules (HCOOH → CO + H2... more ABSTRACT The infrared multiphoton dissociation (IR MPD) of formic acid molecules (HCOOH → CO + H2O) with free electron laser radiation in the 3 μm region (C−H stretch vibrational absorption band) and in the 6 μm region (CO stretch vibrational absorption band) has been achieved using the same laser. Results indicate that initial excitation of this dimer is more efficient for MPD then initial monomer excitation. Carbon isotope-selective MPD has been performed with an isotopic mixture, H12COOH + H13COOH (50% + 50%), at an irradiating wavelength of 5.56 μm. For this mixture, isotopic selectivity s = k12/k13 = 23 has been attained as a ratio of the rate constants of the H12COOH MPD and the H13COOH MPD, respectively. The isotopic selectivity for 13C in the naturally occurring mixture (1.1% of 13C-containing molecules) s = k13/k12 = 22 has been attained at an irradiating wavelength of 5.90 μm.
Doklady Physical Chemistry
The fabrication of high-purity monoisotope silicon has recently stimulated considerable interest ... more The fabrication of high-purity monoisotope silicon has recently stimulated considerable interest , which is caused by the possibility of preparing perfect single crystals of silicon, a basic material for use in microelectronics. The higher heat conduction of 28 Si single crystals compared to that of single crystals with a natural abundance of isotopes was found in [2, 3] and explained in . Recently, the idea of creating a quantum computer based on monoisotope 28 Si doped with 31 P at definite points has been suggested [5]. It is not ruled out that 29 Si possessing a magnetic nucleus can also be used for this purpose. Because of the rich possibilities offered by monoisotope 28 Si for both fundamental studies and advance technology, searching for organosilicon compounds suitable for separation of silicon isotopes is a currently central problem.