Posted by Zhenyu Li on August 04, 2007 at 01:33:47:
I am trying to do CASPT2 calculation on phenol in gas phase. The CASSCF energies I got are similar to what I found in literature, but my CASPT2 energies are about 0.4 eV larger. It interesting that CASPT2 did improved the CASSCF result by giving the correct state ordering, but it is systematically blue shifted.
My CASSCF excited state energies (eV):
4.81 7.59 8.99 9.18 7.91 8.18
My CASPT2 excited state energies:
4.98 6.33 7.11 7.19 8.23 8.28
Experimental energies:
4.51 5.82 6.66 6.66
I checked the molecular orbitals and the CI coefficients from CASSCF, it seems OK. Then it is strange why the CASPT2 energies are wrong, since we don't have many input parameters to play in CASPT2.
My input file is following (Manually MO order changing were made between CASSCF steps):
*================================================================
*&SEWARD &END
Title
phenol molecule
SDipole
Symmetry
X
*----------------------------------------------------------------
Basis set
C.ANO-L...4s3p1d.
C1 0.000000 0.000000 0.938289 Angstrom
C2 0.000000 -1.204130 0.231697 Angstrom
C3 0.000000 -1.187750 -1.162054 Angstrom
C4 0.000000 0.020714 -1.855346 Angstrom
C5 0.000000 1.218342 -1.138927 Angstrom
C6 0.000000 1.215477 0.252424 Angstrom
End of basis
*----------------------------------------------------------------
Basis set
O.ANO-L...4s3p1d.
O1 0.000000 0.050990 2.307462 Angstrom
End of basis
*----------------------------------------------------------------
Basis set
H.ANO-L...2s1p.
H1 0.000000 -0.842564 2.666130 Angstrom
H2 0.000000 -2.148742 0.768185 Angstrom
H3 0.000000 -2.126881 -1.704104 Angstrom
H4 0.000000 0.029949 -2.938644 Angstrom
H5 0.000000 2.165653 -1.666741 Angstrom
H6 0.000000 2.138747 0.818978 Angstrom
End of basis
*----------------------------------------------------------------
Basis set
X....8s8p8d. / Inline
0.0 2
8 1
.024624 .011253 .005858 .003346 .002048 .001324 .000893 .000624
0.15265390
-1.35239027
0.55146299
-0.52189327
0.05083766
0.40642284
-0.42889789
0.14946525
8 1
.042335 .019254 .009988 .005689 .003476 .002242 .001511 .001055
0.09904702
-0.49696896
-0.43148951
-0.26956686
0.16987903
-0.16278425
0.09368379
-0.02488389
8 1
.060540 .027446 .014204 .008077 .004927 .003175 .002137 .001491
0.02233121
0.17555258
0.41874381
0.32371474
0.18974807
-0.03543714
0.03966263
-0.01209007
X 0.000000 -0.304650 0.353576 Angstrom
End of basis
*----------------------------------------------------------------
End of input
*================================================================
*================================================================
*&SCF &END
Title
phenol molecule
Occupied
21 4
End of input
*================================================================
*================================================================
*&RASSCF &END
Title
phenol molecule
Symmetry
1
nActEl
8 0 0
Frozen
14 0
Inactive
7 0
Ras2
0 8
CIRoot
7 10
1 2 3 5 6 8 9
1 1 1 1 1 1 1
LumOrb
End of input
*================================================================
*================================================================
*&RASSCF &END
Title
phenol molecule
Symmetry
1
nActEl
8 0 0
Frozen
14 0
Inactive
7 0
Ras2
0 7
Deleted
0 1
CIRoot
7 7 1
LumOrb
End of input
*================================================================
*================================================================
*&RASSCF &END
Title
phenol molecule
Symmetry
1
nActEl
8 0 0
Frozen
14 0
Inactive
7 0
Ras2
0 9
Deleted
0 1
CIRoot
11 11 1
LumOrb
Iteration
200 50
CIMX
200
End of input
*================================================================
*================================================================
*&RASSCF &END
Title
phenol molecule
Symmetry
1
nActEl
8 0 0
Frozen
14 0
Inactive
7 0
Ras2
0 7
Deleted
0 3
CIRoot
7 7 1
LumOrb
End of input
*================================================================
*================================================================
&CASPT2 &END
Title
phenol molecule
MultiState
7 1 2 3 4 5 6 7
Shift
0.1
End of input
*================================================================