Molcas Forum

tumitumi123

Member

Registered: 2017-06-13

Posts: 16

rassi SOC calculation

Dear all
I am doing a test for Br2, I want to see the split of pi orbital due to SOC, but i did not see it. Is this because of the symmetry that I used? below is the input and output

&gateway
coord
2
bohr
br    0 0  -$RR
br    0 0  $RR
basis=ano-rcc-vdz
group=xy y
ANGM
0 0 0
&SEWARD
Douglas-Kroll 

&scf
&RASSCF
spin=2
nactel=9 0 0
inactive=16 6 2 6
ras2=2 2 0 2
ciroot=4 4 1
symmetry=2
&caspt2
multistate
4 1 2 3 4
>> COPY $WorkDir/xue.JobIph $WorkDir/JOB001

&rassi
NrofJobIphs  
1 1  
  1  
spin orbit
ejob

      ****************************************************************************************************
      *                                                                                                  *
      *                                         Spin-orbit section                                       *
      *                                                                                                  *
      ****************************************************************************************************


       Total energies including SO-coupling:
::    SO-RASSI State  1     Total energy:  -5208.21250334
::    SO-RASSI State  2     Total energy:  -5208.21250334


   Eigenvalues of complex Hamiltonian:
   -----------------------------------

  (Shifted by EVAC (a.u.) =           -5000.0)

        Relative EVac(au)    Rel lowest level(eV)    D:o, cm**(-1)

   1     -208.21250334            0.000000               0.000
   2     -208.21250334            0.000000               0.000


 Weights of the five most important spin-orbit-free states for each spin-orbit state.

 SO State  Total energy (au)           Spin-free states, spin, and weights
 -------------------------------------------------------------------------------------------------------
   1      -208.212503      1 0.5  1.0000
   2      -208.212503      1 0.5  1.0000
 -------------------------------------------------------------------------------------------------------

what is the meaning of Relative EVac(au) and Rel lowest level

shan xue

tumitumi123

Member

Registered: 2017-06-13

Posts: 16

Re: rassi SOC calculation

After I include another casscf calculation in sym=4, I see the split. But I still not quite know the meaning of the output

      ****************************************************************************************************
      *                                                                                                  *
      *                                         Spin-orbit section                                       *
      *                                                                                                  *
      ****************************************************************************************************


 Complex SO-Hamiltonian matrix elements over
 spin components of spin-free eigenstates (SFS):
 (In cm-1. Print threshold:      1.000 cm-1)
 ----------------------------------------------------------------------

  I1  S1  MS1    I2  S2  MS2    Real part    Imag part      Absolute
   3  0.5 -0.5    1  0.5 -0.5        -0.000      1353.619      1353.619
   4  0.5  0.5    2  0.5  0.5        -0.000     -1353.619      1353.619
 ----------------------------------------------------------------------

       Total energies including SO-coupling:
::    SO-RASSI State  1     Total energy:  -5208.21867088
::    SO-RASSI State  2     Total energy:  -5208.21867088
::    SO-RASSI State  3     Total energy:  -5208.20633580
::    SO-RASSI State  4     Total energy:  -5208.20633580


   Eigenvalues of complex Hamiltonian:
   -----------------------------------

  (Shifted by EVAC (a.u.) =           -5000.0)

        Relative EVac(au)    Rel lowest level(eV)    D:o, cm**(-1)

   1     -208.21867088            0.000000               0.000
   2     -208.21867088            0.000000               0.000
   3     -208.20633580            0.335655            2707.238
   4     -208.20633580            0.335655            2707.238


 Weights of the five most important spin-orbit-free states for each spin-orbit state.

 SO State  Total energy (au)           Spin-free states, spin, and weights
 -------------------------------------------------------------------------------------------------------
   1      -208.218671      1 0.5  0.5000   2 0.5  0.5000
   2      -208.218671      1 0.5  0.5000   2 0.5  0.5000
   3      -208.206336      2 0.5  0.5000   1 0.5  0.5000
   4      -208.206336      2 0.5  0.5000   1 0.5  0.5000
 -------------------------------------------------------------------------------------------------------

what is the meaning of I1 I2, which energy belongs to j=3/2? how to identify it?

Ignacio

Administrator

From: Uppsala

Registered: 2015-11-03

Posts: 1,085

Re: rassi SOC calculation

what is the meaning of Relative EVac(au) and Rel lowest level

"Relative EVac" are the energies of the states relative to the vacuum (or to the EVAC value that is given above), i.e., your energies are -5208.2...

"Rel lowest level" are the energies relative to the lowest one in this calculation, i.e., excitation energies from the lowest in the set.

The give basically the same information, but in different units and with different zeros, for convenience.