Subject: Re: CCL:G:convergence criterion in SCF for calculation of polarizability

From: "Thomas R. Cundari" <[email-masked]>
Date: Tue, 19 May 1998 09:48:43 -0500

Dear Patrick,

You must be very careful in calculating polarizability and related nonlinear
optical properties as these require very careful attention to the SCF 
convergence criteria than normal electronic structure calculations. My 
colleague here @ U of of Memphis, Henry Kurtz, has a chapter in an upcoming
issue of Reviews in Computational Chemistry that touches upon this.

In a recent paper in collaboration with Henry (Cundari, Kurtz & Zhou
J Phys Chem, A, 1998, 102, 2962) that investigates the NLO props of 
inorganic complexes we used a convergence of 10^-10 plus several other
options relating to the size of integrals that could be ignored.

Tom Cundari

At 09:26 PM 5/19/98 +0800, you wrote:
>Hello!  In Gaussian 94, the SCF convergence will be finished when a 
>specific density-based convergence criterion (10^-N) is met.  What is the 
>convergence criterion suitable for calculation of polarizability?  Of 
>course, 10^-8 is the best.  However, it will be paid much computational 
>time.  Is it suitable for choosing 10^-4?
>
>Thank you for your attention.
>
>Patrick Pang  
>
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