Re: CCL:G:AM1 under GAUSSIAN ???
- From: Gustavo de Miranda Seabra <seabra (+ at +)
NPD.UFPE.BR>
- Subject: Re: CCL:G:AM1 under GAUSSIAN ???
- Date: Fri, 20 Feb 1998 16:13:16 -0300
I have seen a problem like this once. I feel that the structure optimization
of GAUSSIAN is much better tham of MOPAC. In fact, the problem I have seen
is about structure optimizaton and, while most times MOPAC made just a
little change on the structure (but reaching a local minimum fast), GAUSSIAN
moved completely the structure, taking more time but reaching much better
structures.
-----Original Message-----
From: ACKERMANN Lutz GRL <Lutz.ACKERMANN (+ at +) CALDCRD.elf-atochem.fr>
To: ccl <CHEMISTRY (+ at +) www.ccl.net>
Date: Friday, February 20, 1998 6:14 AM
Subject: CCL:G:AM1 under GAUSSIAN ???
>
>
>Dear Netters,
>we have recently carried out a series of calculations
>using MOPAC/AM1. When we asked academic partners to do some ab initio
>calculations on the same set of compounds we were surprised to find, that
>there
>seems to be an inconcistency between GAUSSIAN/AM1 and MOPAC/AM1,
>concerning the heat capacity Cp. Does anyone know, if this is:
> -> a well known phenomenon/problem/bug
> -> a consequence of a different implementation (deliberate) or
> -> one of the great mysteries of life?
>
>For your orientation I have appended parts of the MOPAC and GAUSSIAN output
>of calcs for the CO2 molecule.
>
>
>Best Regards
>
>Lutz Ackermann
>
>
>_________________________________________________________
>Dr. Lutz Ackermann
>
>Service Chimie Physique, Groupment de Recherches de Lacq
>elf atochem
>R.N 117, B.P. 34, F-64170 Lacq (France)
>Phone: (0033) 5 59 92 67 66 FAX: (0033) 5 59 92 67 65
>e-mail: lutz.ackermann (+ at +) CALDCRD.elf-atochem.fr or lutz (+ at +)
ri.ac.uk
>
>or
>
>phone/FAX: (0033) 5 59 27 65 43
>lutz.ackermann (+ at +) wanadoo.fr
>___________________________________________________________
>
>
>CO2 (AM1)
>
>
>MOPAC 6.0:
> ----------
> CALCULATED THERMODYNAMIC PROPERTIES
> *
> TEMP. (K) PARTITION FUNCTION H.O.F. ENTHALPY HEAT CAPACITY
> ENTROPY
> KCAL/MOL CAL/MOLE CAL/K/MOL
> CAL/K/MOL
>
> 273 VIB. 1.139 203.06527 2.22755
> 1.00258
> ROT. 255. 542.522 1.987
> 12.997
> INT. 290. 745.587 4.215
> 14.000
> TRA. 0.248E+27 1356.305 4.968
> 36.817
> TOT. -80.062 2101.8922 9.1830
> 50.8170
>
> 298 VIB. 1.181 261.82494 2.46932
> 1.20837
> ROT. 278. 592.203 1.987 13.172
> INT. 328. 854.028 4.457 14.380
> TRA. 0.282E+27 1480.509 4.968 37.252
> TOT. -79.829 2334.5371 9.4247
51.6320
>
>
>
>
>
>
>GAUSSIAN:
> --------
>
> ...
>
>Energy= -0.127281006429 NIter= 9.
>
> ...
>
> E (Thermal) CV S
> KCAL/MOL CAL/MOL-KELVIN CAL/MOL-KELVIN
> TOTAL 9.040 7.411 51.623
> ELECTRONIC 0.000 0.000 0.000
> TRANSLATIONAL 0.889 2.981 37.270
> ROTATIONAL 0.592 1.987 13.171
> VIBRATIONAL 7.559 2.443 1.182
> VIBRATION 1 0.886 1.182 0.586
> VIBRATION 2 0.887 1.179 0.583
> ...
>
>
>
>Transforming the Energy given by GAUSSIAN from Hartree to kcal/mol, one
>gets -79.8653 kcal/mol, which is close to the Heat of Formation calculated
>from MOPAC (at 298K), -79.829 kcal/mol. The entropy is also very similar
>between
>the two programs, but the heat capacity differs a lot ( 7.411
CAL/MOL-KELVIN
>in
>GAUSSIAN vs. 9.4247 CAL/K/MOL in MOPAC!!???
>
>-------This is added Automatically by the Software--------
>-- Original Sender Envelope Address: Lutz.ACKERMANN (+ at +)
CALDCRD.elf-atochem.fr
>-- Original Sender From: Address: Lutz.ACKERMANN (+ at +)
CALDCRD.elf-atochem.fr
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