### CASSCF phosphorescence

Posted:

**18 May 2014, 19:29**I have some 'unusual' results for the transition moments in a phosphorescence calculation, that hints at a Dalton problem.

The LiH tests supplied with Dalton check out OK.

The actual system is MgH+ with an uncontracted aug-cc-pVDZ run in C2v (z-axis along the molecular axis). The problem is basis set independent.

Transition moments are labelled as <dipole,SO>. By symmetry, the <x,y> moment should be the same as <y,x> except for a sign. Similarly, the <z,x> should match <z,y>, and <x,z> should match <y,z> in magnitude. This checks out at the HF level, both with SO and with the MNF-SO approximation. It is also OK with a full-CASSCF wavefunction and the SO-MNF, but not with the 'real' SO integrals.

Besides the symmetry problem, the magnitude of the transition moments also depends on which and how many ROOTS that are specified in the *QUADRA section. Specifying e.g. 0 1 0 0 gives different results than 1 1 1 1, and also different if requesting higher roots, like 2 2 2 0, for the same transition of the same symmetry.

The differences are not just numerics. The <x,y> moment is 0.000656 while the <y,x> is 0.009559. The <x,z> is 0.462241 while the <y,z> is 0.117397. The corresponding MNF-SO values are 0.000010 and 0.000463. The HF results suggest that the MNF approximation underestimates the value by roughly a factor of 10.

Excitation energies are OK.

.mol and .dal files are given below

Frank

.DAL:

**DALTON INPUT

.RUN RESPONSE

**INTEGRALS

.SPIN-ORBIT

**WAVE FUNCTIONS

.HF

.MCSCF

*SCF INPUT

.THRESH

1.0d-9

.DOUBLY OCCUPIED

4 1 1 0

*CONFIGURATION INPUT

.SYMMETRY

1

.SPIN MUL

1

.INACTIVE

1 0 0 0

.ELECTRONS

10

.CAS SPACE

5 2 2 0

*OPTIMIZATION

.STATE

1

**RESPON

*QUADRA

.PHOSPHORESCENCE

.ROOTS

1 1 1 1

**END OF

.MOL:

INTGRL

basis set exponent optimization

CO

2 0 1 1.0d-15

1. 1 2 1 1

H 0.00000 0.000000 0.000000

F 5 0

13.0100000

1.9620000

0.4446000

0.1220000

0.0297400

F 2 0

0.7270000

0.1410000

12. 1 3 1 1 1

Mg 0.00000 0.000000 2.000000

F 13 0

47390.0000000

7108.0000000

1618.0000000

458.4000000

149.3000000

53.5900000

20.7000000

8.3840000

2.5420000

0.8787000

0.1077000

0.0399900

0.0148800

F 9 0

179.9000000

42.1400000

13.1300000

4.6280000

1.6700000

0.5857000

0.1311000

0.0411200

0.0093500

F 2 0

0.1870000

0.0595000

The LiH tests supplied with Dalton check out OK.

The actual system is MgH+ with an uncontracted aug-cc-pVDZ run in C2v (z-axis along the molecular axis). The problem is basis set independent.

Transition moments are labelled as <dipole,SO>. By symmetry, the <x,y> moment should be the same as <y,x> except for a sign. Similarly, the <z,x> should match <z,y>, and <x,z> should match <y,z> in magnitude. This checks out at the HF level, both with SO and with the MNF-SO approximation. It is also OK with a full-CASSCF wavefunction and the SO-MNF, but not with the 'real' SO integrals.

Besides the symmetry problem, the magnitude of the transition moments also depends on which and how many ROOTS that are specified in the *QUADRA section. Specifying e.g. 0 1 0 0 gives different results than 1 1 1 1, and also different if requesting higher roots, like 2 2 2 0, for the same transition of the same symmetry.

The differences are not just numerics. The <x,y> moment is 0.000656 while the <y,x> is 0.009559. The <x,z> is 0.462241 while the <y,z> is 0.117397. The corresponding MNF-SO values are 0.000010 and 0.000463. The HF results suggest that the MNF approximation underestimates the value by roughly a factor of 10.

Excitation energies are OK.

.mol and .dal files are given below

Frank

.DAL:

**DALTON INPUT

.RUN RESPONSE

**INTEGRALS

.SPIN-ORBIT

**WAVE FUNCTIONS

.HF

.MCSCF

*SCF INPUT

.THRESH

1.0d-9

.DOUBLY OCCUPIED

4 1 1 0

*CONFIGURATION INPUT

.SYMMETRY

1

.SPIN MUL

1

.INACTIVE

1 0 0 0

.ELECTRONS

10

.CAS SPACE

5 2 2 0

*OPTIMIZATION

.STATE

1

**RESPON

*QUADRA

.PHOSPHORESCENCE

.ROOTS

1 1 1 1

**END OF

.MOL:

INTGRL

basis set exponent optimization

CO

2 0 1 1.0d-15

1. 1 2 1 1

H 0.00000 0.000000 0.000000

F 5 0

13.0100000

1.9620000

0.4446000

0.1220000

0.0297400

F 2 0

0.7270000

0.1410000

12. 1 3 1 1 1

Mg 0.00000 0.000000 2.000000

F 13 0

47390.0000000

7108.0000000

1618.0000000

458.4000000

149.3000000

53.5900000

20.7000000

8.3840000

2.5420000

0.8787000

0.1077000

0.0399900

0.0148800

F 9 0

179.9000000

42.1400000

13.1300000

4.6280000

1.6700000

0.5857000

0.1311000

0.0411200

0.0093500

F 2 0

0.1870000

0.0595000