A BOXCARS investigation of the V–V energy transfer from highly excited SF6 to CS2 and the sensitized photodissociation of CS2

1994 ◽  
Vol 72 (11-12) ◽  
pp. 845-850 ◽  
Author(s):  
L. Wang ◽  
W. E. Jones
Keyword(s):  
Energy Transfer ◽  
Partial Pressure ◽  
Energy Exchange ◽  
Laser Excitation ◽  
Vibrational Energy ◽  
Vibrational Temperature ◽  
Excitation Intensity ◽  
Excitation Energies ◽  
Ir Laser ◽  
Partial Pressures

The BOXCARS technique was used to investigate the vibrational energy transfer between highly excited SF6 and CS2, and for the sensitized photodissociation of CS2. The analysis of data, as reported in our previous studies, to extract vibrational temperature from the CARS signal has been revised in the present work to adjust for the fact that the ground-state population may not be constant. The current investigation suggests that IR laser excitation of SF6 and the energy exchange between excited SF6 and CS2 create a high-lying vibrational energy reservoir in the CS2 vibrational manifold. The rate of energy transfer depends on the partial pressures of SF6 and CS2, and the excitation intensity. The transfer rate shows greater dependence on the partial pressure of SF6 than on the partial pressure of CS2. At higher excitation energies, the energy reservoir leads to photofragmentation products.

A BOXCARS investigation of the interspecies V–V energy transfer from highly excited SF6 to CH4

1996 ◽  
Vol 74 (1-2) ◽  
pp. 34-38
Author(s):  
Lixin Wang ◽  
W. E. Jones
Keyword(s):  
Energy Transfer ◽  
Partial Pressure ◽  
Experimental Error ◽  
Vibrational Energy ◽  
Polyatomic Molecules ◽  
Excitation Intensity

The BOXCARS technique was used to investigate the V–V energy transfer between highly excited SF6 and CH4. The rates and the amounts of energy transferred to both the ν1 and ν3 modes depend strongly on excitation intensity and partial pressure of SF6 and CH4, and within experimental error, the variation of these quantities in both modes is identical, which is contrary to the situation in other polyatomic molecules. The results indicate that V–T energy transfer in CH4 plays an important role in the relaxation of the excess vibrational energy transferred from SF6 to CH4, and that the intermode V–V energy transfer between the ν1 and ν3 modes of CH4 is much faster than the interspecies V–V energy transfer between highly excited SF6 and CH4.

A BOXCARS investigation of the interspecies V–V energy transfer from highly excited SF6 to N2

1995 ◽  
Vol 73 (7-8) ◽  
pp. 505-511
Author(s):  
W. E. Jones ◽  
Lixin Wang
Keyword(s):  
Experimental Data ◽  
Energy Transfer ◽  
Partial Pressure ◽  
Laser Excitation ◽  
Population Distribution ◽  
Maximum Energy ◽  
Energy Increase ◽  
Transfer Processes ◽  
Partial Pressures ◽  
Vibrational Levels

The BOXCARS technique was used to investigate the V–V energy transfer between highly excited SF6 and N2. It was found that a Boltzmann population distribution among vibrational levels of N2 is present by 1 μs after laser excitation of SF6 and is maintained during the energy-transfer processes. The maximum energy transferred to N2 increases linearly with the increase of the average number of photons absorbed [Formula: see text] by SF6 in the range [Formula: see text]. The maximum energy transferred to the N2 vibrational levels increases with the partial pressure of SF6 and decreases with the partial pressure of N2. The apparent rate of energy increase in the N2 vibrational levels increases with both partial pressures of SF6 and N2. However, both the rate and the amount of energy transferred to N2 vibrational levels depend more strongly on the partial pressure of SF6 than on the partial pressure of N2. A model calculation produces a reasonable fit to the experimental data.

Vibrational Energy Transfer in Silane and Silane Mixtures

1976 ◽  
Vol 31 (10) ◽  
pp. 1203-1209 ◽  
Author(s):  
Willi Janiesch ◽  
Helmut Ulrich ◽  
Peter Hess
Keyword(s):  
Experimental Data ◽  
Energy Transfer ◽  
Relaxation Time ◽  
Vibrational Relaxation ◽  
Energy Exchange ◽  
Vibrational Energy ◽  
Vibrational Energy Transfer

Abstract The vibrational relaxation time for pure SiH4 is 0.10, 0.083 and 0.072 μsec atm (±30%) at 295 K, 375 K and 462 K. For SiH4 diluted in He, D2 and H2 the corresponding numbers are 0.16, 0.081 and 0.031 μsec atm (± 30%) at 295 K. The binary two-level theory has been used to deter-mine the four V -R, T rates in the system SiH4 -CH4, and the rate for V-V exchange between SiH4 and CH4 from experimental data. From the Schwartz-Slawsky-Herzfeld-formula for V -T and V -V, T processes an equation is derived describing V -R and V -V, R energy exchange. The different models are compared with experimental data, especially with those found for the system SiH4 -CH4.

A study of vibrational-rotational energy exchange in a shock tube

1971 ◽  
Vol 325 (1561) ◽  
pp. 197-206 ◽  
Keyword(s):  
Energy Transfer ◽  
Energy Exchange ◽  
Room Temperature ◽  
Vibrational Energy ◽  
Theoretical Calculations ◽  
Relaxation Times ◽  
Vibrational Energy Transfer ◽  
Para Hydrogen ◽  
Schlieren Method ◽  
Hydrogen Mixtures

Vibrational relaxation times have been measured in CO 2 + H 2 mixtures from 344 to 742 K by a laser-schlieren method. Normal and para hydrogen mixtures have been used. The scatter in the results is small and there is excellent agreement with a recent ultrasonic measurement at room temperature. The results are not in accord with the theoretical calculations of Sharma. They show that both rotational-vibrational and translational-vibrational energy transfer must be important for this case and throw light on the importance of rotational-vibrational energy transfer in other systems.

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