Hi everybody:
I had a problem with a calculation recently, and was
wondering if anybody might be able to offer some insight to my problem.
I'm trying to do a TDDFTcalculation for a compound CP2TICL2 . First i do
optimization calculation, and after this with the optimized structure, i do
calculation in order to obtain the excitation energy and oscillator strength
by using response module and of course i have obtained ideal excitation
energies for them. but i am wonder, for the results of excitation of singlet
to triplet, the results is follows:

Starting calculation of SINGLET-SINGLET excitation energies
.........
Starting matrix-vector product in Davidson code
*************************************************************************
* *
* Final excitation energies from Davidson algorithm *
* *
* Number of loops in Davidson routine = 10 *
* Number of matrix-vector multiplications = 200 *
* *
* Oscillator strength *
* (not multiplied by degeneracy) *
* Nr Excitation energy Symmetry dE wrt prev cycle *
* Hartree eV Hartree *
* 1: 0.08310 2.26134 0.1128E-02 A 0.11E-09 *
* 2: 0.09132 2.48496 0.1522E-04 A 0.97E-10 *
* 3: 0.10889 2.96303 0.2409E-01 A 0.65E-08 *
* 4: 0.12254 3.33453 0.4703E-02 A 0.34E-08 *
* 5: 0.12344 3.35896 0.2112E-02 A 0.73E-09 *
* 6: 0.12450 3.38773 0.4049E-03 A 0.77E-09 *
* 7: 0.12950 3.52379 0.1127E-01 A 0.77E-08 *
* 8: 0.13050 3.55106 0.3293E-02 A 0.20E-08 *
* 9: 0.13447 3.65921 0.2143E-03 A 0.34E-09 *
* 10: 0.13555 3.68839 0.1652E-01 A 0.39E-08 *
* 11: 0.13740 3.73885 0.5770E-02 A 0.19E-07 *
* 12: 0.13827 3.76256 0.1629E-04 A 0.28E-08 *
* 13: 0.13942 3.79393 0.3281E-02 A 0.51E-08 *
* 14: 0.14085 3.83286 0.8232E-02 A 0.25E-08 *
* 15: 0.14457 3.93393 0.1674E-01 A 0.76E-08 *
* 16: 0.14571 3.96490 0.1564E-01 A 0.14E-08 *
* 17: 0.14684 3.99578 0.1005E-01 A 0.55E-09 *
* 18: 0.14849 4.04061 0.1605E-01 A 0.73E-08 *
* 19: 0.15420 4.19595 0.2552E-04 A 0.49E-09 *
* 20: 0.15856 4.31469 0.3557E-01 A 0.48E-06 *
* *
* Major MO -> MO transitions for the above excitations *
* *
* Excitation Occupied to virtual Contribution *
* 1 : 38a -> 39a 1.00 *
* 2 : 37a -> 39a 0.99 *

.................

Starting calculation of SINGLET-TRIPLET excitation energies
...............

Starting matrix-vector product in Davidson code
Eigenvalues of small (approximate) problem
**************************************************************************
* *
* Final excitation energies from Davidson algorithm *
* *
* Number of loops in Davidson routine = 4 *
* Number of matrix-vector multiplications = 80 *
* *
* Oscillator strength *
* (not multiplied by degeneracy) *
* Nr Excitation energy Symmetry dE wrt prev cycle *
* Hartree eV Hartree *
* 1: 0.07812 2.12588 0.1307E-01 A 0.73E-08 *
* 2: 0.08616 2.34464 0.4172E-03 A 0.93E-08 *
* 3: 0.09373 2.55062 0.2478 A 0.99E-08 *
* 4: 0.11065 3.01085 0.1797 A 0.19E-07 *
* 5: 0.11727 3.19106 0.4780E-03 A 0.37E-07 *
* 6: 0.12050 3.27899 0.5643E-01 A 0.15E-07 *
* 7: 0.12394 3.37271 0.1754 A 0.88E-08 *
* 8: 0.12432 3.38304 0.2206 A 0.18E-07 *
* 9: 0.12584 3.42438 0.1119 A 0.49E-07 *
* 10: 0.12659 3.44475 0.1506E-01 A 0.64E-07 *
* 11: 0.12884 3.50583 0.1294 A 0.34E-07 *
* 12: 0.12997 3.53671 0.2119E-02 A 0.16E-07 *
* 13: 0.13243 3.60358 0.4303E-02 A 0.13E-07 *
* 14: 0.13369 3.63800 0.3510E-01 A 0.16E-06 *
* 15: 0.13500 3.67341 0.8108E-02 A 0.12E-07 *
* 16: 0.13545 3.68590 0.1845 A 0.89E-07 *
* 17: 0.13901 3.78263 0.4636E-03 A 0.19E-08 *
* 18: 0.13945 3.79471 0.1928 A 0.63E-08 *
* 19: 0.14452 3.93264 0.5580E-02 A 0.17E-07 *
* 20: 0.14740 4.01106 0.2838E-04 A 0.25E-07 *
* *
* Major MO -> MO transitions for the
...............

my problem is that should not the oscillator strength be zero?(because it is
spin-prohibited excitation) and i do calculation use gaussian 98, b3lyp,
tddft, it is sure all the values of oscillator strength of singlet to
triplet are zero.
and what is the meaning of these oscillator strength in the excitation of
singlet to triplet? is it can be understand the similar meaning such as in
singlet and singlet excitation?

thank you in advance.

your sincerely
 wang.
Received on 2003-05-04 10:09:13