scholarly journals Thermalization in Infrared Multiple Photon Induced Reactions. The Pressure Dependence of the Trans → Cis Isomerization of Crotonitrile

1990 ◽  
Vol 10 (4) ◽  
pp. 227-238 ◽  
Author(s):  
Joseph R. Guckert ◽  
Robert W. Carr
Keyword(s):  
Laser Radiation ◽  
Pressure Dependence ◽  
Pressure Range ◽  
Laser Pulses ◽  
Low Pressure ◽  
Trans Form ◽  
Collisional Regime

The infrared multiple photon trans → cis isomerization of crotonitrile was studied over the pressure range 0.02 torr to 10 torr at fluences of approximately 4J/cm2 using collimated TEA CO2 laser radiation at 942 cm-1. Only minor quantifies of fragmentation products were found at these conditions. At pressures of 0.1 torr or less, the trans form was completely converted to cis form by about 5000 laser pulses. On increasing the pressure a collisional regime was entered in which photostationary states were reached with fewer pulses and having smaller conversions than at low pressure. Both the number of pulses and the conversion decreased monotonically with increasing pressure. The tactic of driving the reaction in the exothermic direction gave evidence that the reaction does not occur solely by thermal isomedzation even in the highly eollisional 10 torr experiments, but that it still has a nonthermal component due to laser induced isomerization.

Dynamic Viscosity of Compressed Water to 10 Kilobar and Steam to 1500°C

1969 ◽  
Vol 11 (2) ◽  
pp. 189-205 ◽  
Author(s):  
E. A. Bruges ◽  
M. R. Gibson
Keyword(s):  
Gaseous Phase ◽  
Dynamic Viscosity ◽  
Low Temperatures ◽  
Pressure Range ◽  
Low Pressure ◽  
Temperature Range ◽  
Inversion Temperature ◽  
Pressure Steam ◽  
Correlating Equations ◽  
First Time

Equations specifying the dynamic viscosity of compressed water and steam are presented. In the temperature range 0-100cC the location of the inversion locus (mu) is defined for the first time with some precision. The low pressure steam results are re-correlated and a higher inversion temperature is indicated than that previously accepted. From 100 to 600°C values of viscosity are derived up to 3·5 kilobar and between 600 and 1500°C up to 1 kilobar. All the original observations in the gaseous phase have been corrected to a consistent set of densities and deviation plots for all the new correlations are given. Although the equations give values within the tolerances of the International Skeleton Table it is clear that the range and tolerances of the latter could with some advantage be revised to give twice the existing temperature range and over 10 times the existing pressure range at low temperatures. A list of the observations used and their deviations from the correlating equations is available as a separate publication.

Unprecedented CO2 adsorption behaviour by 5A-type zeolite discovered in lower pressure region and at 300 K

2021 ◽  
Author(s):  
Akira Oda ◽  
Suguru Hiraki ◽  
Eiji Harada ◽  
Ikuka Kobayashi ◽  
Takahiro Ohkubo ◽  
...  
Keyword(s):  
Pressure Range ◽  
Co2 Adsorption ◽  
Low Pressure ◽  
Lower Pressure ◽  
Dft Studies ◽  
Adsorption Behaviour ◽  
Zeolite Sample ◽  
Pressure Region ◽  
Type Zeolite ◽  
Efficient Adsorbent

The NaCaA-85 zeolite sample which works as an efficient adsorbent for CO2 at RT and in low pressure range was found and its specificity is nicely explained by the model composed of CO2 pinned by two types of Ca2+ ions through far-IR and DFT studies.

scholarly journals An ICR Study of an Association Reaction at Low Pressure

1980 ◽  
Vol 87 ◽  
pp. 305-306
Author(s):  
M.J. Mcewan ◽  
V. G. Anicich ◽  
W.T. Huntress ◽  
P. R. Kemperer ◽  
M. T. Bowers
Keyword(s):  
Pressure Range ◽  
Rate Coefficient ◽  
Low Pressure ◽  
Second Order ◽  
Radiative Association ◽  
Association Reaction

An ICR investigation of the association reactionCH3+ + HCN CH3.HCN+has shown the reaction follows second order kinetics over the pressure range 1 × 10-6 to 3 × 10-4 Torr with a rate coefficient of 2 × 10-10 cm3s-1. These results can be interpreted in terms of a saturated 3-body or radiative association mechanism.

scholarly journals Sputtering of Neutral Molecules and Molecular Ions From the Adenine Crystal Surface Induced by the UV Picosecond Laser Pulse

1982 ◽  
Vol 1 (1) ◽  
pp. 37-43 ◽  
Author(s):  
V. S. Antonov ◽  
V. S. Letokhov ◽  
Yu. A. Matveyets ◽  
A. N. Shibanov
Keyword(s):  
Laser Radiation ◽  
Kinetic Energy ◽  
Crystal Surface ◽  
Picosecond Laser ◽  
Laser Pulses ◽  
Molecular Ions ◽  
Laser Radiation Intensity ◽  
Ion Sputtering ◽  
Absorbed Energy ◽  
Picosecond Laser Pulse

This paper presents the results of observation of sputtering of neutral molecules and ions from the crystal adenine surface induced by fourth-harmonic Nd:YAG laser radiation with a pulse duration of 30 ps. The energy fluence of laser pulses was in the region (1–3) × 10−4 J/cm2. The kinetic energy distribution of the sputtered molecules spreads up to 0.7 eV. The experiment shows that the threshold of adenine molecular ion sputtering is connected with absorbed energy density in upper layers of the crystal surface but not by laser radiation intensity.

GENERATION OF ULTRASHORT ELECTRON BUNCHES IN NANOSTRUCTURES BY FEMTOSECOND LASER PULSES

2007 ◽  
Vol 17 (03) ◽  
pp. 571-576
Author(s):  
A. GLADUN ◽  
V. LEIMAN ◽  
A. ARSENIN ◽  
O. MANNOUN ◽  
V. TARAKANOV
Keyword(s):  
Thin Film ◽  
Laser Radiation ◽  
Femtosecond Laser ◽  
Electric Field ◽  
Surface Plasmon ◽  
Laser Pulses ◽  
Photoelectric Effect ◽  
Femtosecond Laser Pulses ◽  
Electron Bunches ◽  
Internal Photoelectric Effect

We present numerical investigation of anomalous internal photoelectric effect which is realized in thin film (< 100 nm) structures by surface plasmon (SP) excitation and its interaction with primary laser radiation. SP electric field gain and electron temperature in the SP field have been calculated.

Application of Pressure-Sensitive Paints to Low-Pressure Range

2005 ◽  
Vol 19 (1) ◽  
pp. 9-16 ◽  
Author(s):  
Tomohide Niimi ◽  
Masaki Yoshida ◽  
Makoto Kondo ◽  
Yusuke Oshima ◽  
Hideo Mori ◽  
...  
Keyword(s):  
Pressure Range ◽  
Low Pressure ◽  
Pressure Sensitive

Excimer Laser Interaction with Metals

1992 ◽  
Vol 285 ◽  
Author(s):  
W.W. Duley ◽  
G. Kinsman
Keyword(s):  
Experimental Data ◽  
Laser Radiation ◽  
Excimer Laser ◽  
Metal Surfaces ◽  
Laser Pulses ◽  
Radiative Properties ◽  
Uv Laser ◽  
Laser Interaction ◽  
Excimer Laser Radiation

ABSTRACTExcimer laser radiation may be used to process metal surfaces in a variety of novel ways. The simplest of these involves the use of UV laser pulses for ablation. Ablation occurs as the result of both vaporization and hydrodynamical effects. Experimental data related to these processes will be discussed. In addition, it will be shown how specific irradiation regimes can yield metal surfaces with unique radiative properties.

scholarly journals Лазерно-индуцированные пространственно-периодические структуры на поверхности титана в среде н-гексана при различном давлении

2020 ◽  
Vol 46 (15) ◽  
pp. 51
Author(s):  
Д.А. Кочуев ◽  
К.С. Хорьков ◽  
А.С. Черников ◽  
Р.В. Чкалов ◽  
В.Г. Прокошев
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Laser Radiation ◽  
Pressure Range ◽  
Titanium Surface ◽  
Surface Structures ◽  
Femtosecond Laser Radiation ◽  
Periodic Surface ◽  
Laser Induced Plasma ◽  
Scanning Electron

The paper presents the results of processing titanium surface in n-hexane at various pressures by femtosecond laser radiation. The effect of laser-induced plasma on the nature of the formation of periodic surface structures in the pressure range from 6 mbar to 22 bar is considered. The study of the surface of the processed samples was carried out using scanning electron microscopy. The dependence of the period of obtained laser-induced periodic surface structures on the pressure in working vessel and the treatment regime is shown.

scholarly journals Modification of Aerosol Gold Nanoparticles by Nanosecond Pulsed-Periodic Laser Radiation

Nanomaterials ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 2701
Author(s):  
Kirill Khabarov ◽  
Messan Nouraldeen ◽  
Sergei Tichonov ◽  
Anna Lizunova ◽  
Alexey Efimov ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Laser Radiation ◽  
Gas Flow ◽  
Laser Pulses ◽  
Radiation Absorption ◽  
Sintering Process ◽  
Spherical Nanoparticles ◽  
Shrinkage Curve ◽  
Size Modification ◽  
Pulse Energies

This study investigates the processes of interaction of nanosecond pulsed-periodic laser radiation with the flow of aerosol agglomerates of gold nanoparticles synthesized in a spark discharge. Nanoparticles in a gas flow are spatially separated nano-objects whose interaction with each other and with the walls of an experimental cell was insignificant. Therefore, the energy absorbed by nanoparticles was used only for their own heating with further shape and size modification and on heat transfer to the surrounding gas. In the research, we used laser radiation with wavelengths of 527 and 1053 nm at pulse energies up to 900 µJ and pulse repetition rates up to 500 Hz. The dynamics of changes in the nanoparticles size during their sintering process depending on the laser pulses energy is characterized by an S-shaped shrinkage curve. Complete sintering of the initial agglomerates with their transformation into spherical nanoparticles is achieved by a series of impacting laser pulses. The result of nanoparticles’ laser modification is largely determined by the pulse energy and the efficiency of the nanoparticles’ radiation absorption.

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