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 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.

Measurement of the vibrational energy-transfer rates in mixtures of polyatomic molecules

1993 ◽  
Vol 57 (2) ◽  
pp. 89-93 ◽  
Author(s):  
J. S. Bakos ◽  
P. N. Ign�cz ◽  
A. L�rincz ◽  
Zs. S�rlei ◽  
J. Szigeti
Keyword(s):  
Energy Transfer ◽  
Vibrational Energy ◽  
Polyatomic Molecules ◽  
Vibrational Energy Transfer ◽  
Transfer Rates

Efficiencies of additives in the transfer of vibrational energy in ethylene and nitrous oxide

1958 ◽  
Vol 248 (1255) ◽  
pp. 445-459 ◽  
Keyword(s):  
Nitrous Oxide ◽  
Energy Transfer ◽  
Vibrational Energy ◽  
Energy Levels ◽  
Polyatomic Molecules ◽  
Ultrasonic Velocities ◽  
High Velocity Impacts ◽  
Good Energy ◽  
Motion Measurements ◽  
Efficient Transfer

Using ethylene or nitrous oxide as test molecules which contain different atoms and exhibit different internal modes of motion, measurements of the dispersion of ultrasonic velocities have been used to obtain information about vibrational energy transfer in the pure gases, and with a number of polyatomic molecules as additives. Much more efficient transfer is found with many of these additives than in self collisions. Even molecules such as benzene which are relatively inefficient in self collisions are good energy transfer catalysts in hetero-collisions. Mechanisms of energy transfer additional to the ‘high velocity impacts’ of Landau & Teller are discussed. In hetero-collisions with polyatomic molecules, vibration-vibration transfers offer one possibility. Wrestling collisions or profound perturbations of the energy levels of the vibrators by dipole fields also appear to be important.

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