[AMBER] resp charge calculation

From: jit mukherjee <jitiitkgp.gmail.com>
Date: Thu, 9 Aug 2012 06:14:13 +0530

Dear Amber Users,

In the website page http://www.teokem.lu.se/~ulf/Methods/resp.html, the
method of calculating the resp charge using Turbomole is given:

RESP with Turbomole

   1. Optimise the structure with QM.

   2. If it is an UHF calculation, you need to have natural orbitals. If
   you do not:
   Insert into the control file the following keywords and rerun ridft
   $natural orbitals file=natural
   $natural orbital occupation file=natural

   3. Run makepoints to get the points where you will calculate the
   electrostatic potential (ESP).
   Select Turbomole (t), Ball (b), 3.0, 0.3, ChelpG (c), 10000, 8 , and
   Turbomole (non-default values highlighted).
   This gives the file esppoints.
   Note that moloch only writes out at the most 10 000 ESP points. If you
   want more than that, you need to construct several files and concatenate
   the results.
   Therefore, you should probably modify the distance between the points
   (in green above), until you get approximately 10 000 points.

   Old version (<5.8):

   4. Insert the suggested rows into the control file (in the beginning to
   avoid already existing keywords).

   5. Run moloch (RHF) or moloch2 (UHF) to get the potentials and also the
   Mulliken charges.
   moloch2 is stupid and does not copy the file esppoints to the new
   directory. Therefore, you have to do:
   cd moloch_n_dir
   cp ../esppoints .
   The calculation takes ~30 minutes and the result is in

   6. This file can be read by changepot as detailed

With the new (>5.7) version of Turbomole, some changes are needed:

   1. Insert in the control file
   $pointval geo=point pot fmt=xyz

   and then the list of coordinates from the file esppoints
   2. Run
   ridft -proper >logm
   3. The results is in the file tp.xyz

It seems that it is the esp charge that is calculated by this procedure.
Can the esp charge be regarded as the resp charge?

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Received on Wed Aug 08 2012 - 18:00:03 PDT
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