[molpro-user] unexpected imaginary frequency

Charles E Cotton ccotton at purdue.edu
Sat Mar 24 01:08:05 GMT 2012

I used the experimental geometry for formamide to do a CCSD(T)/AVDZ geom opt and subsequent frequency calculation.

The optimization converges after a few cycles, but the resulting freq calculation results with one imaginary frequency.

This structure should be a minimum, and ideas why I'd get an imaginary at approx 30CM-1?

More information about the Molpro-user mailing list