CCL:G: Hessian matrix in Cartesian coordinates by Gaussian.



 Sent to CCL by: "Roman D Gorbunov" [rgorbuno(0)aecom.yu.edu]
 Dear CCL Subscribers,
 I need to calculate the Hessian matrix in Cartesian coordinates.
 I searched for the answer in the Interned found this:
 http://www.ccl.net/chemistry/resources/messages/2005/10/03.007-dir/
 It is written that first I have to calculate the checkpoint file.
 Then I have to use "formchk name.chk name.fchk" to get a formated
 file.
 And finally I have to use a script called "demofc" to extract the
 Hessian matrix given in the Cartesian coordinates.
 I have a problem with the last step. I do not know how exactly should I use the
 "demofc". I also cannot find any useful information about that.
 Could anybody pleas help me with that?
 By the way, I checked the formated checkpoint file (name.fchk). It contains some
 information about the system, but I did not find there anything about Hessian
 matrix. May be I have to put some additional keywords into the Gaussian input
 file to force Gaussian to calculate the Hessian matrix?
 Roman