Vibrational relaxation in OCS mixtures. Part 1.—Measured relaxation times for pure OCS and for OCS in mixtures with helium-4, helium-3, normal deuterium, ortho-deuterium, HD, normal hydrogen and para-hydrogen

1976 ◽  
Vol 72 (0) ◽  
pp. 417-422 ◽  
Author(s):  
C. J. S. M. Simpson ◽  
P. D. Gait ◽  
J. M. Simmie
Keyword(s):  
Vibrational Relaxation ◽  
Relaxation Times ◽  
Para Hydrogen ◽  
Helium 4 ◽  
Measured Relaxation ◽  
Normal Hydrogen ◽  
Helium 3

scholarly journals Picosecond-Duration Vibrational Relaxation Kinetics in the Excited S1 State of Perylene and Anthracene Molecules

1983 ◽  
Vol 3 (1-6) ◽  
pp. 249-261 ◽  
Author(s):  
A. Freiberg ◽  
T. Tamm ◽  
K. Timpmann
Keyword(s):  
Steady State ◽  
Luminescence Spectrum ◽  
Vibrational Relaxation ◽  
Vibrational Energy ◽  
Streak Camera ◽  
Relaxation Times ◽  
Temporal Behavior ◽  
Vibrational Energy Relaxation ◽  
The Matrix ◽  
Measured Relaxation

We present and discuss the results of a direct observation of the picosecond range temporal behavior of vibronic lines in the luminescence spectrum of the matrix-isolated perylene and anthracene molecules. A novel subtractive dispersion mount of monochromators in conjunction with the synchroscan streak camera has been used. From spectrochronograms measured at different excitation wavelengths the vibrational energy relaxation times have been obtained. These are in the range of 20–30 ps and are most probably determined by the existence of the phonon bath of the matrix. A comparison of the measured relaxation constants with those estimated from the steady-state hot luminescence spectrum has been made.

On the interpretation of measured rotational and vibrational relaxation times. II. Sudden change experiments

1976 ◽  
Vol 54 (15) ◽  
pp. 2372-2379 ◽  
Author(s):  
Huw Owen Pritchard
Keyword(s):  
Shock Wave ◽  
Relaxation Time ◽  
Vibrational Relaxation ◽  
Normal Mode Analysis ◽  
Relaxation Times ◽  
Sudden Change ◽  
Heat Bath ◽  
Mode Analysis ◽  
Wave Excitation ◽  
Measured Relaxation

This paper examines, in terms of the normal-mode analysis developed earlier (Part I), the nature of relaxations in which a diatomic gas, highly diluted in a heat bath of inert gas atoms, is subjected to a sudden change as in shock-wave excitation or laser schlieren experiments.It is shown in detail how the observed relaxation time in a shock-wave excitation to a fixed final temperature depends on the initial temperature. At the same time, it is confirmed that the characterisation as 'mainly rotational' of the measured relaxation time in H2 when it is heated from room temperature to 1500 K in a shock wave is perfectly plausible.On the other hand, the calculations show that in laser schlieren experiments in which the v = 1, J = 1 level of H2 is overpopulated, the vibrational relaxation time of H2 at the temperature in question is recovered, although interesting effects should appear if other J levels were populated initially, or if the experiments were carried out at much higher ambient temperatures.The calculations also demonstrate that it is not generally possible to derive relaxation times by following the variation in population of any particular level of the molecule: multiple overshoots sometimes occur, and apparent relaxation times both longer or shorter than the true relaxation times could often result from attempts to follow level populations as a function of time.

Vibrational Relaxation Times in Oxygen

1959 ◽  
Vol 30 (6) ◽  
pp. 1614-1615 ◽  
Author(s):  
Morris Salkoff ◽  
Ernest Bauer
Keyword(s):  
Vibrational Relaxation ◽  
Relaxation Times

Vibrational Relaxation Times in Nitrogen

1957 ◽  
Vol 27 (5) ◽  
pp. 1149-1155 ◽  
Author(s):  
S. J. Lukasik ◽  
J. E. Young
Keyword(s):  
Vibrational Relaxation ◽  
Relaxation Times
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