Subject: Hyperpolarizabilities in MOPAC93

From: [email-masked] (Marianna Fanti)
Date: Mon, 18 Apr 1994 13:16:25 +0200

Hi Netters.

I'm running MOPAC7 in order to calculate first and second order 
hyperpolarizabilities. The results, I'm obtaining, seem to indicate 
that there are some problems. For various molecules such as benzene,  
naphthalene, and anthracene the values of alpha, beta, and gamma are 
correct at low perturbation energies. At higher values of omega 
(1.5, 2.0 eV), alpha, beta, and gamma explode. The larger the conjugated 
system, the lower the perturbation energy at which the NLO values go berserk. 
For C70, at omega=0.649 eV, the calculations result in an unphysically  
high value of alpha and a beta (SHG) markedly 
different from zero (for C70 beta MUST be equal to zero).
I was wondering if somebody has encountered the same type of difficulties
and if there is a way out
 
Marianna Fanti

Istituto di chimica "G. Ciamician"
via Selmi n.2
40126 Bologna
Italy
Tel. 051-259495
e-mail: [email-masked]
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