On the probability of intermolecular energy transfer in polar molecules

✍ Scribed by Hyung Kyu Shin

• Publisher: Elsevier Science
• Year: 1967
• Tongue: English
• Weight: 284 KB
• Volume: 1
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(67)85069-3

✦ Synopsis

An expression is developed for the probability of intermolecular energy transfer Pin polar molecules for particular orientations on the basis of the Lennard-Jones-dipole-quadrupole interaction energy. The temperature dependence of P is briefly discussed.

In calculating the probability of intermolecular energy transfer P, potential energy functions composed of two terms (repulsive and attractive) such as the Lennard-Jones (12-6) potential and the Morse potential have often been assumed [l, 21. Such potentials are a better representation than single term (repulsive) functions since the attractive part is present in the true interaction in which the approaching molecules are "speeded up" in a potential well of depth D. For polar molecules, however, the two-tezm functions are inadequate, and explicit account has to be taken of the interaction of the permanent charges on the colliding molecules. There have beeq several investigations of the energy transfer between the vibrational and translational motions in polar molecules assuming the Krieger potential 13-51. Although it considers the importance of the dipole-dipole interaction, the orientation dependence of the intermolecular energy transfer cannot be examined with this potential rigorously, since it is an orientation-averaged function. There is experimental evidence that P for polar molecules such as So2 and CH3Cl decreases to a minimum and then increases in "a normal fashion" as the temperature increases [6-81.