Re: QMMM Question

From: McGuire, Kelly (
Date: Tue Oct 18 2022 - 23:45:09 CDT

Yep, it was activated by QwikMD, thanks for help.

One more question, how do I get MOPAC to use GPUs for the QM region in the QMMM, and can ORCA use GPUs now for its QM region? Thanks!

Dr. Kelly L. McGuire

PhD Biophysics

Department of Physiology and Developmental Biology

Brigham Young University

LSB 3050

Provo, UT 84602

From: <> on behalf of Marcelo C. R. Melo <>
Sent: Tuesday, October 18, 2022 3:33 PM
To: <>; Mcguire, Kelly <>
Subject: Re: namd-l: QMMM Question

Hi Kelly,

NAMD offers the user the ability to run a second executable after each QM calculation. This is used when there is a need to post-process the raw QM output at each simulation step, instead of just using the gradients and partial charges used in "regular" QM/MM simulations.

Your QwikMD setup must have accidentally set the "qmSecProc" keyword, so all you need to do is remove it from your NAMD config files.


On Mon, Oct 17, 2022 at 3:42 PM Mcguire, Kelly <<>> wrote:
I am running a test system using QwikMD to setup a quick QMMM with MOPAC. MOPAC is installed correctly and works fine. I run my QMMM using NAMD 2.14 (non-CUDA) and it seems to run the QM part fine. I get a qmmm_0.input.out and there are no errors. But on the NAMD side, my log file gives the error:

FATAL ERROR: Error running second command for QM calculation

What second command is this referring to?

Dr. Kelly McGuire
Herzik Lab - Postdoc
Chemistry/Biochemistry Department
Natural Science Building, 4104A, 4106A, 4017

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