Re: CCL:Second negative frequency

 Your second value (36 cm-1) could easily be positive given the error
 associated with normal mode calculations (+/-50 cm-1 or so). Perhaps
 you have only one imaginary frequency ...
 David
 Ivan wrote:
 >
 > Dear CCL'ers
 >
 > I am working with programme GAMESS and an present time I am facing some
 > problems with TS.I am simulating H-transfer from NH3 bonded to the rest of
 > molecule to another "free" NH3 forming "free"NH4.
 > In TS there are two imaginary frequencies ( 1. - value about 975, that
 > correspond to H-transfer and 2.- value about 36 )  and  can't get rid of
 > this second little negative frequency. Firstly I tried to use keywords
 > PURIFY in $STATPT and $FORCE groups to purify hessian matrix but with no
 > results. Then I tried several approachs to find better TS, but all resulted
 > to the same TS. And IRC calculations in both directions are correct,
 because
 > according to IRC's this TS connects appropriate minimas on both side of the
 > hill.Finally I wanted to to perform IRC folowing the second negative
 > frequency, but GAMESS did not accept the specified frequency ( in $IRC
 > group ).
 >
 > I would very appreciate any help,advice or trick.
 >
 > Stanislav Ivan
 > student
 >
 > -= This is automatically added to each message by mailing script =-
 > CHEMISTRY[ AT ]ccl.net -- To Everybody  | CHEMISTRY-REQUEST[ AT ]ccl.net --
 To Admins
 > MAILSERV[ AT ]ccl.net -- HELP CHEMISTRY or HELP SEARCH
 > CHEMISTRY-SEARCH[ AT ]ccl.net -- archive search    |    Gopher:
 gopher.ccl.net 70
 > Ftp: ftp.ccl.net  |  WWW: http://www.ccl.net/chemistry/   | Jan: jkl[ AT ]ccl.net
 --
 ________________________________________________________________
 David Turner                                             Synt:em
 Senior Modeling Scientist              Parc Scientifique G.Besse
 Computational Drug Discovery                         30000 Nimes
 email: dturner[ AT ]syntem.com                                 France
 Tel:
 Switchboard: +33 (0)4 66 04 86 66      Fax: +33 (0)4 66 04 86 67
 Direct Line: +33 (0)4 66 04 22 85
 ________________________________________________________________
           Discover New Drugs, Discover Synt:em
                  http://www.syntem.com
 ________________________________________________________________