Re: CCL:the ground state calculation with g98

Hello,
 Do you use a spin restricted or unrestricted method?
 If restricted, try the unrestricted one and use Guess=Alter
 only for the exchange of beta HOMO and LUMO, although you
 expect a closed shell. I had a similar problem with some
 cations of Metal-phthalocyanines
 (you can see P. Toman, S. Nespurek, K. Yakushi:
 J. Porphyrins Phthalocyanines 2002; 6: 556-562)
 Btw. what molecule do you calculate?
 Yours,
 Petr Toman
 On Fri, 13 Jun 2003, Dai Bing wrote:
 > Dear CCLers,
 >    A simple Opt calculation with g98, HOMO and LUMO are the
 > same symmetry, such as PI. But the energy of LUMO is lower than
 > the one of HOMO, what's the problem? and how to resolve?
 >    The following two methods don't work. :(
 >    1. Stable=opt.
 >    2. change the symmetry of the molecule, HOMO and LUMO
 > change to A1 and B1, then use guess=alter.
 >
 >    Can someone help me? Thanks.
 >
 > = = = = = = = = = = = = = = = = = = = =
 >
 > ===============
 > Bing Dai,
 > Ph.D. Candidate,
 > Laboratory of Bond Selective Chemistry,
 > University of Science and Technology of China,
 > Chinese Academy of Sciences.
 > Hefei, Anhui, 230026,
 > People's Republic of China,
 > Tel.: 86-551-3603418,3603748,3601084
 > Fax.: 86-551-3602969
 > Http://www.bsc.ustc.edu.cn/~bdai
 > E-mail: bdai)at(mail.ustc.edu.cn
 > ===============
 >
 >
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