Hello,
I am trying to reproduce the charges of alpha-D-glucopyranose form:
Restrained electrostatic potential atomic partial charges for
condensed-phase simulations of carbohydrates
R. J. Woods and R. Chappelle
Journal of Molecular Structure: THEOCHEM
Volume 527, Issues 1-3, 4 August 2000, Pages 149-156
using GAMESS-US and R.E.D. III.3
The problem I face is that I obtain too small charges for all the
heavy atoms in the molecule compared to the ones in the paper above.
I use the same approach as described in the paper:
Charges I obtain Charges from Woods & Chappelle
1 O1 -0.3074 **** -0.6887
2 HO1 0.3037 **** 0.4772
3 C1 -0.0319 **** 0.2552
4 H1 0.1292 **** 0.1186
5 C2 -0.0307 **** 0.2474
6 H2 0.1281 **** 0.0978
7 O2 -0.3825 **** -0.6640
8 H2O 0.2603 **** 0.4281
9 C3 -0.0266 **** 0.1484
10 H3 0.1228 **** 0.1188
11 O3 -0.3477 **** -0.6732
12 H3O 0.2783 **** 0.4357
13 C4 -0.0385 **** 0.0492
14 H4 0.1298 **** 0.0754
15 O4 -0.3830 **** -0.6607
16 H4O 0.2614 **** 0.0754
17 C5 -0.0329 **** 0.2047
18 H5 0.0963 **** 0.1295
19 O5 -0.1371 **** -0.4966
20 C6 -0.0139 **** 0.2543
21 H61 0.0984 **** -0.0080
22 H62 0.0984 **** 0.0003
23 O6 -0.5796 **** -0.6805
24 H6O 0.4052 **** 0.4266
I understand that charges depend on conformation but the differences
are simply too big.
This problem also appear on all monosaccarides that I had tried to
compute the charges for and even for smaller molecules.
I am fairly new to charge derivation and I tried to solve this for two
weeks without any success. It is obvious that I do a mistake
somewhere.
GAMESS installation is working properly as it passed all the tests.
Also the structures minimized within REDIII charge derivation process
are OK as tested with another QM software at the same level of
description.
I think the things go wrong somehere in the RESP procedure but I can't
seee where.
I am using RESP-C2 charge derivation method with qwt= 0.0100 and CHELPG
Here is the GAMESS input header:
! Single point to get MEP - Input generated by R.E.D.-III
!
$CONTRL ICHARG=0 MULT=1 RUNTYP=ENERGY MOLPLT=.T.
MPLEVL=0 UNITS=ANGS MAXIT=200 EXETYP=RUN
SCFTYP=RHF
COORD=UNIQUE $END
$SCF DIRSCF=.T. CONV=1.0E-06 $END
$SYSTEM TIMLIM=5000 MWORDS=32 MEMDDI=0 $END
$BASIS GBASIS=N31 NGAUSS=6 NDFUNC=1 $END
$GUESS GUESS=HUCKEL $END
! CHELPG/CONNOLLY CHARGES
$ELPOT IEPOT=1 WHERE=PDC OUTPUT=BOTH $END
$PDC PTSEL=CHELPG CONSTR=NONE $END
$DATA
and,
Here is the RESP input header:
RESP-C2 project. RESP input generated by R.E.D.
&cntrl
ioutopt=1, iqopt=1, nmol=1, ihfree=1, irstrnt=1, qwt= 0.0100
&end
Any help would be greatly appreciated,
Andrei
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Received on Fri Nov 13 2009 - 01:00:03 PST
