Hyperpolarizabilities of diatomic molecules: The effects of vibration and rotation

✍ Scribed by David M. Bishop; Brenda Lam

• Publisher: Elsevier Science
• Year: 1988
• Tongue: English
• Weight: 390 KB
• Volume: 143
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(88)87058-1

✦ Synopsis

The inductive properties of a non-polar diatomic molecule in a static non-uniform electric field are best described in terms of its dipole polarizability (a), second hyperpolarizability (y), quadrupole-quadrupole polarizability (C) and dipole-dipole-quadrupole polarizability (B). We present formulae for these quantities which take into account both vibration and rotation.

We do so in a more general way than hitherto by placing an electric field and field gradient along an arbitrary laboratory axis rather than along a molecular axis. These formulae are then compared with those which can be obtained by accounting for rotation by classical orientational averaging, which involve polarizabilities defined with respect to molecular axes. Results for H: and Hz show that the "electronic" contributions are similar in both treatments, but the "vibrational" and "rotational" contributions are not. This is particularly so when the molecules are not in the lowest vibrational state.