CCL: Isotopic Vibrational Frequencies in g09
- From: "Dom Esan" <desan2[A]uic.edu>
- Subject: CCL: Isotopic Vibrational Frequencies in g09
- Date: Thu, 17 Sep 2015 20:29:17 -0400
Sent to CCL by: "Dom Esan" [desan2]![uic.edu]
Good day all,
I ran some vibrational frequency calculations using different atomic isotopes in
g09 but I'm getting some "weird" results.
Basically, I used the checkpoint file from a previous frequency calculation of a
non-substituted molecule (CH2NH2, say) and then used "readfc and
readisotopes" to calculate the frequencies of substituted isotopes of C or
N (13C or 15N). The resultant frequencies from the isotopic calculations were
*higher* than those of the non-substituted molecule(s). One would expect the
frequencies of the heavier isotopes to be *lower*.
Does anyone have any suggestions as to what might be wrong?
All calculations were done on a metal cluster with the metal atoms frozen.
Thank you for your time and anticipated assistance.