problem with CASPT2 vibrations
Jean M. Standard
standard at ilstu.edu
Fri Sep 27 23:12:33 BST 2002
Molpro users,
I am trying to calculate vibrational frequencies at the CASPT2 level
for a carbene in its lowest singlet electronic state. The carbene
is a substituted methylene, for example, F-C-I, for which because of
the iodine I am using the SBKJC effective core potential and
corresponding double zeta quality basis set (augmented with polarization
functions).
I have no problems obtaining the equilibrium geometry (the level is
CASPT2(18,12)). However, I get an error when I try to calculate the
frequencies at the CASPT2 level.
Here is the pertinent section of the input file I am using:
-----------------------------
rhf
multi;
occ,9,3;
closed,0,0;
wf,18,1,0
rs2c;
occ,9,3;
closed,0,0;
wf,18,1,0;
optg,numerical;
show rcf, rci, theta
frequencies, numerical
----------------
After the optimization completes and the program enters the frequency
routine, I get the following error message in the output file:
PROGRAM * FREQUENCIES Author: F. Eckert
CALCULATING HARMONIC VIBRATIONAL FREQUENCIES FOR RS2C
Incrementing variable CX by +/- 0.010 BOHR
? Error
? incorrect ldact
? The problem occurs in ciinit
GA ERROR termxy
GA ERROR
0:0:termxy:: 0
0: ARMCI aborting 0 (0).
-------------------
This is on an AMD Athlon dual processor Linux system running Molpro 2002.1.
Has anyone had this problem? Is it possible to calculate CASPT2 frequencies
for a system like this? Is my approach wrong? I _have_ been successful
in calculating the frequencies of F-C-I at the CASSCF(18,12) level. (I am
also interested in the frequencies of the first excited singlet state, and
no minimum can be located on the PES for the excited state at the CASSCF
level - CASPT2 or MRCI is required because the potential well is rather
shallow - thus, I would like to be able to calculate the frequencies of
both states using CASPT2 in order to compare them.)
Any suggestions are appreciated.
Thanks, Jean
--
---------------------------------------------------------------------
Jean M. Standard standard at ilstu.edu
Department of Chemistry
Illinois State University Phone: (309) 438-7700
Normal, IL 61790-4160 FAX: (309) 438-5538
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