You can use ECP in Gaussian calculation (see
pseuso=read).
Please have a look at this
Theor. Chem. Acc. 2009, 122, 119, on iodine
calculation.
abu
On Mon, Dec 6, 2010 at 11:10 AM, Roy Jensen JensenRH _ MacEwan.ca
<owner-chemistry/a\ccl.net> wrote:
Sent to CCL by: Roy Jensen [JensenRH_._MacEwan.ca]
In Gaussian 03, it is apparently not possible to use ECP basis sets
using the GEN keyword. I thus need to find an all-electron basis set
for iodine. I was surprised to discover that several basis sets very
poorly predict the I2 bond length, with an experimental bond length of
270 pm.
(Basis sets from the EMSL Basis Set Exchange Library)
aug-cc-pVDZ-PP: r = 3.3428 Åbr>
aug-cc-pVTZ-PP: FAILS WITH AN INTERESTING ERROR (see below)
The input file is
***********************
#P UB3PW91/GEN opt
Optimized geometry of I2 at the UB3PW91/<various> level of theory.
0 1
I
I 1 R1
R1=2.7
<basis set from EMSL>
************************
ERROR in aug-cc-pVTZ-PP: note the net bond length from the two
calculations. The first adds to about 2.7 Å-- very nice -- but the
second calculation, which puts the origin at the center of mass,
*incorrectly calculates the bond lengths!!*
**************************
(Enter /global/scratch/software/gaussian/g09/l202.exe)
Input orientation:
---------------------------------------------------------------------
Center Atomic Atomic
Coordinates (Angstroms)
Number Number Type
X Y
Z
---------------------------------------------------------------------
1 53
0 0.000000 0.000000
0.919904
2 53
0 0.000000 0.000000
1.780096
---------------------------------------------------------------------
Stoichiometry I2
Framework group D*H[C*(I.I)]
Deg. of freedom 1
Full point group
D*H NOp 8
Largest Abelian subgroup D2H NOp
8
Largest concise Abelian subgroup C2 NOp 2
Standard orientation:
---------------------------------------------------------------------
Center Atomic Atomic
Coordinates (Angstroms)
Number Number Type
X Y
Z
---------------------------------------------------------------------
1 53
0 0.000000 0.000000
0.430096
2 53
0 0.000000 0.000000
-0.430096
---------------------------------------------------------------------
Rotational constants (GHZ): 0.0000000
10.7645060 10.7645060
Leave Link 202 at Sun Dec 5 10:09:11 2010, MaxMem=
33554432 cpu:
0.0
**************************
Anyone have any idea why the aug-cc-pVxZ-PP basis sets do so poorly?
The 6-311G** basis set, also from EMSL, returns an accurate bond
length of 2.706 Å
Thanks,
Dr. Roy Jensen
(==========)-----------------------------------------¤
Chemistry, Grant MacEwan University
Room 5-172J, 10700-104 Avenue
Edmonton, AB T5J 4S2
780.633.3915
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