Frequency calculation again

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baki
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Frequency calculation again

#1 Post by baki » Fri Jul 01, 2005 7:17 am

Dear Sir
I have performed several calculation on alkane and cikloalkane. I found some very strange behaviour.
If I begin the optimalisation from a godd geometry
(optimised by gaussian with good basis) I got 2 big negativ frequency(around 8-900 cm-1) If I change the geometry according the normal vektor of these mode I got one or two every strange frequencies.(around 1600-1700 cm-1)
I have already try to increase the accuracy, the box size, using the ISYM command.
Can anbody give me som advice?
(If I performed the calculation on surface, I got quite reasonable frequncies)
imre
Last edited by baki on Fri Jul 01, 2005 7:17 am, edited 1 time in total.

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Frequency calculation again

#2 Post by admin » Fri Jul 01, 2005 1:48 pm

please have a look at the reply to your posting concerning CH4., June 1st
Last edited by admin on Fri Jul 01, 2005 1:48 pm, edited 1 time in total.

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