The effect of intermolecular interactions on the second hyperpolarisability of the ammonia heptamer

✍ Scribed by J. Waite; M.G. Papadopoulos

• Publisher: Elsevier Science
• Year: 1985
• Tongue: English
• Weight: 339 KB
• Volume: 114
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(85)85137-x

✦ Synopsis

The second hype~o~b~~ y of (NH& computed by She CHF fT EB CNDD method is presented Tfie effect of the H-bond and other environmental interactions on y is discussed.

It has been repcrted that a smgle peptide unit in an

o-helix is associated with a dipole moment of 3.5 D [ I] _ However, theoretical. considerations indicate an increase in the peptide dipole moment by polarisation, due to H-bonds in the a-helix yielding values up to 5 Thus it was thought useful to consider the change in the average second hyperpolarisability 7 * induced by H-bond and other environmental interactions. This is an important property because it measures the non-linear response of a molecule to fields set up by the charge distribution of the environment. Further the development of considerable electric fields generated by organic molecules of importance [I], the implications of which have been analysed [1,4,5], makes