Subject: Re: CCL:Hyperpolarizabilities in MOPAC93

From: [email-masked] (Rolfe G. Petschek)
Date: Mon, 18 Apr 94 08:15:10 -0400

>Subject: CCL:Hyperpolarizabilities in MOPAC93
>
>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. 
>
>Marianna Fanti
>
>Istituto di chimica "G. Ciamician" via Selmi n.2 40126 Bologna Italy

Mopac uses coupled time dependent hartree fock equations to calculate
frequency dependent (hyper) polarizabilities.  The iterative method
which is currently implemented for solving these equations will not
converge to a correct answer unless the frequency is below the frequency
of the lowest lying (symmetry allowed, 1's CI) excited state.

Rolfe G. Petschek			[email-masked]
Associate Professor of Physics		[email-masked]
Case Western Reserve University		(216)368-4035 
Cleveland Oh 44106-7079