Re: [AMBER] MCBP force constants

From: Pengfei Li <>
Date: Thu, 26 Jul 2018 11:08:38 -0400

Hi Steve,

I would suggest you to use other than MCPB due to is much more user-friendly than MCPB.

For your question, Z-matrix and Seminario methods are all based on the Hessian analysis in QM calculations. There are keyword IOp(7/33=1) in Gaussian you need to specify if you want to use the Z-matrix method, which will print out the internal force constant matrix in the log file of the force constant calculation step. While the Seminario method is based on the fchk file generated after that step (whether you specify that IOp will not influence the fchk file generated). You can refer the Gaussian calculations in the tutorial for your Gaussian calculations.

Besides that, you need to specify in the MCPB or modeling about which method you are using (mentioned in the tutorials).

Hope it helps,

> On Jul 25, 2018, at 1:23 PM, Seibold, Steve Allan <> wrote:
> I am working my way through MCBP (not tutorial. I have gotten to the point of
> "Gaussian based Side Chain Model Optimization and Frequency Calculation". At this point from my understanding I must select the method for force constant calculation..i.e. Z-matrix or the Seminario method...However, I don't understand how I am to select.?? Is this a method I select in Gaussian (I can't find it in G03)?
> Thanks, Steve
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Received on Thu Jul 26 2018 - 08:30:02 PDT
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