MRSF Transition dipole moment

Questions
#1

Dear users,

I recently tried the MRSF-TDDF method. Here is the output :

 Excited state   1: excitation energy (eV) =       0.9342
 Total energy for state   1:                 -1572.21760926 au
    <S**2>     :  0.0000
    Trans. Mom.:  0.0000 X   0.0000 Y   0.0000 Z
    Strength   :     0.0000000000
    S(    1) --> S(    1) amplitude =  0.9930 alpha

 Excited state   2: excitation energy (eV) =       2.6996
 Total energy for state   2:                 -1572.15273141 au
    <S**2>     :  0.0000
    Trans. Mom.:  0.1516 X   0.3062 Y   0.1769 Z
    Strength   :     0.0064015330
    D(  127) --> S(    1) amplitude =  0.1555
    D(  127) --> V(    1) amplitude =  0.1636
    D(  129) --> S(    1) amplitude = -0.1900
    D(  129) --> V(    1) amplitude = -0.2203
    S(    2) --> S(    1) amplitude =  0.6091 alpha
    S(    2) --> V(    1) amplitude =  0.5388 alpha
    S(    2) --> V(    2) amplitude = -0.2458 alpha

 Excited state   3: excitation energy (eV) =       2.8081
 Total energy for state   3:                 -1572.14874580 au
    <S**2>     :  0.0000
    Trans. Mom.:  0.0310 X   0.0653 Y  -0.1620 Z
    Strength   :     0.0014450456
    D(  124) --> S(    1) amplitude =  0.7042
    D(  125) --> S(    2) amplitude = -0.2345
    D(  126) --> S(    1) amplitude = -0.4111
    D(  127) --> S(    2) amplitude = -0.1967
    D(  128) --> S(    1) amplitude = -0.2131
    D(  128) --> V(    1) amplitude = -0.1636

I noticed that the calculation gave me a non-zero value for the “strength” and also for the transition dipole moment. I was curious to know how this value is computed and whether it has a physical meaning, given that, a priori, no spin–orbit coupling is being calculated.

Could you also please confirm the nature of my excited states? If I am not mistaken, my first state corresponds to an open-shell singlet state, and the second a mix between the singlet ground state and an open shell singlet.

Thank you in advance !

#2

MR-SF-TDDFT jobs print transition dipoles and oscillator strength relative to the lowest SF state and not relative to the reference (as is done in TDDFT). I believe the manual points it out.

#3

Yes, you are right, I missed this information in the manual. Thank you very much for your quick reply !