The pre-exponential factor in activated reorientational processes

✍ Scribed by C. Brot

• Publisher: Elsevier Science
• Year: 1969
• Tongue: English
• Weight: 424 KB
• Volume: 3
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(69)80242-3

✦ Synopsis

JXferent approaches to the pre-exponential factor for processes in which a rot&or crosses a potential barrier by thermal fluctuations are compared. It is shown thd Eyring's treatment, in its classicaL limit, is equivalent u) that of Bauer and. furthermore, that Eyring's entropy of activation hzs no intrinsic qualitative significance.

For simple two-well potenkials erplicit pre-exponential factors are given: for the plane rotator the pre-e.xponential factor is approximately equal to the freq?lency OF Libration in the well whereas in the case of the space rotator, it involves the square of this frequency.

Finally the assum@ons underlying the above-mentioned treatments are discussed, and a word of warning given against the hasty interpretation of constant pressure experimeatal results.