Phosphorescence calculation: symmetry problems for C1 molecule

[esmuigors]

Dear Dalton people,

I have tried to run a phosphorescence calculation with full spin–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 spin–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

[kennethruud]

Hi!

You also need to specify the number of excited states you want to consider using the keyword .ROOTS, and this is probably which is the reason for the failure of your calculation.

I note you use the .SPIN-ORBIT keyword. This will calculate both one- and two-electron spin-orbit integrals. With almost 1500 basis functions, I would advise using the two-electron spin-orbit operator, and rather use some effective one-electron spin-orbit operator, as also done in the work you refer to. Please check the manual for how to calculate e.g. the effective charge one-electron spin-orbit operator, replacing .PHOSPHORESCENCE with .ECPHOS.


Best regards and good luck,

Kenneth

[esmuigors]

Thank You, prof. Ruud!
The necessity of .ROOTS was indeed mentioned in the manual ("This keyword sets up the calculation so that no further response input is required except .ROOTS"). Quite a logical requirement...

One more question. As I understand from the manual, to use only two-electron SO integrals, I need to replace .PHOSPHORESCENCE with .ECPHOS; but should the .SPIN-O in **INTEGRALS section persist then? The only alternative I found for it in the Manual was the .MNF-SO, which, as far as I understand, corresponds to a further approximation and requires .MNFPHO, not .ECPHOS.

With sincere gratitude,
Igors

[kennethruud]

The program will calculate the necessary one-electron integrals on its own, so you can remove the keyword .SPIN-ORBIT under **INTEGRALS.

Best regards,

Kenneth

[xiongyan21]

Dear Prof. Ruud
The .mol input provided here is not easy to try, thus I have tried C2v symmetric ethene with and without .SPIN-O, and got the same error
...

Very Best Regards!

[kennethruud]

Could you please provide the output file? And please note that once you introduce symmetry, you need to make sure you include roots (excited states) in the relevant irreps (one number for each irrep on the line following .ROOTS).

[xiongyan21]

Dear Prof. Ruud
Thanks a lot for your advice.
Actually I used Avogadro to draw ethene, then roughly optimized it only with the built-in molecular force field for this test, which is automatically recognized as C2v symmetry. Now it works!
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Date and time (Darwin) :
Host name :
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I wish to know How I can force it to run as C1 or other symmetry. It seems that I cannot find the methodology in the manual.

Very Best regards!

[kennethruud]

Use NoSymmetry on the line of the input where you give the number of Atomtypes, see Section 27.1 of the Dalton 2018 manual.


Kenneth

[xiongyan21]

Dear Prof. Ruud
Thanks a lot again for your advice.
I have not downloaded Dalton2018,yet, but I will do it according to your previous introduction.
Now the NoSymmetry ethene can gave the following
...
Phosphorescence electric dipole transition rates
...

Phosphorescence transition rate from excited state no. 2
(Triplet->singlet transition, high-temperature limit)


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It is quite natural for it to agree reasonably with the previous calculation results.

...


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It seems there is no problem to finish this kind of calculation.
Very Best Regards!