SUMMARY: Normal mode scan

[Jens Antony <antony %! at !% math.fu-berlin.de>]

Dear CCL,
 here are the answers to my request from last Friday.
 Thanks again.
 Jens Antony
 --
 Free University Berlin
 Institute for Mathematics II
 Arnimallee 2-6
 D-14195 Berlin , Germany

-- Request --
 Dear CCL,
 1) How can I scan a potential energy surface along a vibrational normal
 mode with Gaussian or another molecular electronic structure program
 automatically ?
 2) How can I increase the precision of the normal modes printed with
 Gaussian ?

-- Answer 1 --
 Hi Jens,
 you might try POLYRATE. It is a program
 (designed by Prof. Joel Bowman and others) to
 calculate vibrational frequencies and more by
 going beyond the harmonic oscillator approximation.
 Add the HPFREQ option to the FREQ command.
 You can find a very thorough documentation of
 G98 at:
 http://www.gaussian.com/techinfo.htm
 Stefan Fau

-- Answer 2 --
 >1) How can I scan a potential energy surface along a vibrational normal
 I have a very crude fortran program that, when you give it the hpmodes
 output for a mode, will create a multi step g98 input file that scans (and
 computes what you want) along a mode.  It is not automatic, and it is
 rather ugly, but it seems to work for me.  I'd be happy to send you a copy
 if you'ld like.
 >2) How can I increase the precision of the normal modes printed with
 The hpmodes keyword will do this.
 Steve Williams

-- Answer 3 --
 >1) How can I scan a potential energy surface along a vibrational normal
 G98 claims to be able to do this using freq as an option to IRC, alas that
 is not the case.  The gaussian people says that it will work in rev. B.
 Please do let me know if you get an answer to this question.
 Theis Ivan Soelling

-- Answer 4 --
   The FREQ=HPModes option will print out the normal modes to higher
 precision.
   Douglas J. Fox
 --