On the use of Herman-Wallis factors for diatomic molecules

Herman-Wallis factors describing the effects of vibration-rotation interact ion on the intensities of infrared and Raman spectra of diatomic molecules can be useful in analyzing spectroscopic data. Accurate analytic approximat ions based on the Dunham potential model and a series expansion of the tran sition operator have been derived by many authors using different theoretic al techniques. However, when the methods or the theoretical results become too cumbersome to apply, they lose their usefulness, especially now that ac curate numerical programs to solve the radial Schrodinger equation and calc ulate the matrix elements directly are available. In the present paper, we comment briefly on some recent examples of the good use of Herman-Wallis fa ctors as well as some misuses. (C) 2001 Elsevier Science Ltd. All rights re served.