Subject: Re: CCL:**** Fatal Problem: The largest alpha MO coeffient is 0.12116834D+04

From: [email-masked]
Date: Wed, 29 Dec 1999 13:14:07 +0100 (MET)

Such large MO coefficients can only arise if the overlap matrix has
a very small eigenvalue. Perhaps something went wrong with the
basis input?

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From: Karl Irikura <[email-masked]>
Date: Wed, 29 Dec 1999 08:57:39 -0500

Do you have diffuse functions in your basis set?  With the small C-C
distances in your molecule, diffuse functions may give
linear-dependence problems in the basis set.  Try deleting the most
diffuse function from each C atom, or try a code that will delete
functions automatically (e.g., Gaussian98, ACES II).

I hope this helps--good luck!

Karl I.

At 12:14 PM 12/28/1999 +0800, you wrote:
>Dear netters,
>
>	When I used g94 to perform a mp2 optimization on the molecule:
>1,3-buta-diyne. I got the error message shown in the title. 
>	Similarly, when I performed a CIS calculation on the same molecule, a
>similar error  result.
>	Any help and advice will be highly appreciated.
>	Thanks in advance.
>
>
>Best Regards,
>
>
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