### Author Topic: how to calculate spin-orbit coupling with CC2/ADC(2)?  (Read 2942 times)

#### oferf

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##### how to calculate spin-orbit coupling with CC2/ADC(2)?
« on: October 07, 2019, 10:31:59 AM »
Dear all,
I'm trying to calculate Spin-Orbit Coupling between S1 and T1 states at either the CC2 or ADC(2) level.
In the control file I type:
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`\$ricc2  cc2\$laplace conv=6\$excitations  irrep=a nexc=1 multiplicity=1  irrep=a nexc=1 multiplicity=3  tmexc  operators=(diplen,soc) freq=0.0d0 istates=(a{1} 1) fstates=(a{3} 1)`
but it doesn't yield the desired type of calculations.

does anyone has some experience with this type of calculations?

Ofer.

#### oferf

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##### Re: how to calculate spin-orbit coupling with CC2/ADC(2)?
« Reply #1 on: October 07, 2019, 03:06:55 PM »
update:
I can get the transition moments between two excited state by writing:
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`\$ricc2  adc(2)\$laplace conv=6\$rx2c\$excitations  irrep=a nexc=3 multiplicity=1  irrep=a nexc=4 multiplicity=3  tmexc momdrv istates=all fstates=all operators=(diplen,soc) freq=0.0d0`but the ouput file doesn't show any implementation of the SOC operator.

For transition between singlet and a triplet I get this text in the output file for example:
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`ADC(2)   Transition moments for pair    2 a        3 a  operator     left TM        right TM  Transition Strength Transition and Operator of different multiplicity. Transition and Operator of different multiplicity. Transition and Operator of different multiplicity.       oscillator strength (length gauge)   :      0.00000000`
the SOC calculation between S1 and T1 (or any other triplet for that matter) is still missing.
« Last Edit: October 07, 2019, 03:08:33 PM by oferf »

#### christof.haettig

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##### Re: how to calculate spin-orbit coupling with CC2/ADC(2)?
« Reply #2 on: November 18, 2019, 11:34:16 AM »
This is not yet implemented. It is only available between singlet GS and triplet ES.