### Phosphorescence calculation: symmetry problems for C1 molecule

Posted:

**29 Dec 2018, 19:03**Dear Dalton people,

I have tried to run a phosphorescence calculation with full spinâ€“orbit operator in Dalton 2016.2, but the program complained about "3 A" and "3 B operators of symmetry 1" not being included, and that the symmetry of specified operators does not match. I believe there is some problem with the input, as I have never run any similar calculation before. The molecule itself, however, has symmetry C1, so I presume the symmetry mentioned is the frequency symmetry (I mean, as in polarizability calculations)?! But how can I specify the right input?

In addition, the spinâ€“orbit integrals were calculated to be zero. Does this have something to do with the symmetry problem? I suspected it is the ECP included in that basis set which causes the error, as the "most relativistic parts" of the molecule are then ousted from the calculation. However, I found an article with some Dalton developers among authors, and they explicitly state that using ECP is fine and "gives results within 15% accuracy" relative to the 4c-calculation. If so, then where is my mistake? Please give me some advice.

I believe there is a mishmash in my mind with respect to relativistic calculations, so please apologize for any dumb thing I have written above. It seems OK when I read papers by others but a complete disaster if I try to do it myself.

Also, I wish You merry (past) Christmas a happy New Year

I have tried to run a phosphorescence calculation with full spinâ€“orbit operator in Dalton 2016.2, but the program complained about "3 A" and "3 B operators of symmetry 1" not being included, and that the symmetry of specified operators does not match. I believe there is some problem with the input, as I have never run any similar calculation before. The molecule itself, however, has symmetry C1, so I presume the symmetry mentioned is the frequency symmetry (I mean, as in polarizability calculations)?! But how can I specify the right input?

In addition, the spinâ€“orbit integrals were calculated to be zero. Does this have something to do with the symmetry problem? I suspected it is the ECP included in that basis set which causes the error, as the "most relativistic parts" of the molecule are then ousted from the calculation. However, I found an article with some Dalton developers among authors, and they explicitly state that using ECP is fine and "gives results within 15% accuracy" relative to the 4c-calculation. If so, then where is my mistake? Please give me some advice.

I believe there is a mishmash in my mind with respect to relativistic calculations, so please apologize for any dumb thing I have written above. It seems OK when I read papers by others but a complete disaster if I try to do it myself.

Also, I wish You merry (past) Christmas a happy New Year