Posted by Claire Loison on December 10, 2009 at 13:14:13:

Dear molcas users,

For the first time I am willing to calculate some electronic excitation energies and oscillator strengths using a basis including rydberg-type functions.

The system is a "simple" conjugated aromatic planar molecule studied in Cs group (naphthol). Following some published papers (eg Rubio et al, Chem. Phys. 179 (1994), Roos et al. in Ad. Chem. Phys Vol 93 (1996) ), I first constructed a basis set using a cation CASSCF calculation and GENANO, and then I add this contracted rydberg basis to an ano-s basis. Now I have done some CASSCF calculation and found a rydberg MO in the CAS. so far so good. In a second step I want to use the keyword DELETE to put it away but i am not sure how it works.

Here are my questions :

1) how to estimate the validity of the ANO

contraction, and the result of genano ?

how to interpret the fig file ?

here is my input for GENANO after a casscf

calculation . Is it the right way to

use the keyword RYDBERG ?

------------------

&GENANO &END

Title

naphthol cation for rydberg basis set

sets

1

Center

X

RYDBERG

End of input

--------------------

2) after the first casscf, the MO 8 in symmetry 2 is the rydberg MO i want to get rid of in the cas.

there are 55 MO in symmetry 2.

here is the casscf input i use:

------------

&RASSCF &END

Title

Naphthol

nActEl

10 0 0

Inactive

32 1

Ras2

0 13

LUMORB

SYMMETRY

1

SPIN

1

CIROOT

7 7 1

ITER

30 100

ALTER

1

2 8 55

DELETE

0 1

End of input

-------------------

after the calculation i get a new rasorb and jobiph file. Is the deleted rydberg MO now labeled 8 or 55 ?

=> i supposed it is 55..

should i delete it again for next calculations ?

=> i supposed yes.

When i use the new rasorb or jobiph for a next calculation, should i alter the order again or not ?

=> i supposed not

I did not and used as a second input for the next casscf the following input :

-------------------------

&RASSCF &END

Title

Naphthol

nActEl

10 0 0

Inactive

32 1

Ras2

0 13

JOBIPH

SYMMETRY

1

SPIN

1

CIROOT

7 7 1

ITER

30 100

DELETE

0 1

End of input

-------------------------

What bothers me is that I get this part in the output :

-----------------------------

Molecular orbitals for symmetry species 2: a"

Orbital 11 12 13 14 15 16 55

Energy .0000 .0000 .0000 .0000 .0375 .0408 .0000

Occ. No. .9201 .1327 .2183 .0645 .0000 .0000 .0000

.... further down

53 X 2pz -.0035 -.1572 -.0682 -.0013 .0282 .0526 -.8534

54 X 3d1- .0067 -.0004 -.0035 -.0064 .1203 1.0508 -.0206

55 X 3d1+ -.0026 .0010 .0033 -.0004 1.0507 -.1249 .0413

---------------------------

so the orbital 55 is at energy 0, as if it would be part of the CAS !

do delete orbitals have no energy ?

it seems that the rydberg MO are the number

15,16,55, all of them are out of the cas.

So the rydberg MO of the cas was rotated against

a valence MO.

Should I first force now the other rydberg MO (15 and 16) to be part of the cas (either by increasing the cas, or by altering the order of MO and deleting them afterwards ) ? what would you choose ?

Thanks for reading this email to the end !

Claire Loison