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Pages: 1

#1 2018-10-06 08:37:10

maheshg
Member
Registered: 2018-09-25
Posts: 9

[SOLVED] Spin-orbit coupling between siglet and triplet states

Dear All,

I am interested in computing the spin-orbit coupling constants between singlet and triplet states at the singlet-triplet crossing by which the efficiency of the inter system crossing can be determined.

As a test, I prepared an input for soc calculation of acrolein molecule based on the example given in the manual (http://molcas.org/documentation/manual/node33.html).

***INPUT***
                                                                                                                                                               

&GATEWAY
  Title=  Acrolein  molecule
  coord  =  acrolein.xyz;  basis  =  STO-3G;  group=  c1
  AMFI
&SEWARD
&SCF
&RASSCF
  Spin=  1;  Nactel=  6  0  0;  Inactive=  12;  Ras2=  5
  CiRoot=  2  2  1
&CASPT2
  Frozen=  4
  MultiState=  2  1 2
>>COPY  $Project.JobMix  JOB001
&RASSCF
  LumOrb
  Spin=  3;  Nactel=  6  0  0;  Inactive=  12;  Ras2=  5
  CiRoot=  3  3  1
&CASPT2
  Frozen=  4
  MultiState=  3  1  2  3
>>COPY  $Project.JobMix  JOB002
&RASSI
  Nr  of  JobIph=  2  2  3;  1 2;  1  2  3
  Spin
  EJob

I have copied the relevant part of the output below. 

      ****************************************************************************************************
      *                                                                                                  *
      *                                         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  1.0 -1.0    1  0.0  0.0        13.345       -30.259        33.071
     5  1.0  1.0    1  0.0  0.0        13.345        30.259        33.071
     6  1.0 -1.0    2  0.0  0.0        -8.626        19.659        21.468
     6  1.0 -1.0    4  1.0  0.0        -7.988        18.280        19.949
     7  1.0  0.0    3  1.0 -1.0         7.988        18.280        19.949
     7  1.0  0.0    5  1.0  1.0        -7.988        18.280        19.949
     8  1.0  1.0    2  0.0  0.0        -8.626       -19.659        21.468
     8  1.0  1.0    4  1.0  0.0         7.988        18.280        19.949
     9  1.0 -1.0    2  0.0  0.0         7.859       -17.171        18.884
     9  1.0 -1.0    4  1.0  0.0         7.813       -17.093        18.794
    10  1.0  0.0    3  1.0 -1.0        -7.813       -17.093        18.794
    10  1.0  0.0    5  1.0  1.0         7.813       -17.093        18.794
    11  1.0  1.0    2  0.0  0.0         7.859        17.171        18.884
    11  1.0  1.0    4  1.0  0.0        -7.813       -17.093        18.794
 ----------------------------------------------------------------------

I am not able to understand the output completely (particularly, I1, S1, I2 and S2). For eg: If I want to estimate the efficiency of inter system crossing between S1 and T2 states, which number in the above table should be considered?

Thank you

Mahesh

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#2 2018-10-06 08:47:27

Ignacio
Administrator
From: Uppsala
Registered: 2015-11-03
Posts: 1,085

Re: [SOLVED] Spin-orbit coupling between siglet and triplet states

I may be mistaken, but I think I1 and I2 are the indices of the states. You have two singlets in JOB001 and three triplets in JOB002, so I'd guess the indices are:

S_0: 1
S_1: 2
T_1: 3, 4, 5
T_2: 6, 7, 8
T_3: 9, 10, 11

S1, S2 are the total spins of the states: 0.0 for singlets, 1.0 for triplets. MS1, MS2 are the m_s quantum numbers of the states: 0 for singlets, -1, 0, -1 for triplets. If you want the couplings between S_1 and T_2, that's between indices 2 and 6,7,8, so:

     6  1.0 -1.0    2  0.0  0.0        -8.626        19.659        21.468
     8  1.0  1.0    2  0.0  0.0        -8.626       -19.659        21.468

but check the energies reported by RASSI to make sure these are the states you want.

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#3 2018-10-06 09:04:59

maheshg
Member
Registered: 2018-09-25
Posts: 9

Re: [SOLVED] Spin-orbit coupling between siglet and triplet states

Dear Ignacio,

Thank you very much for the prompt response. That helped me a lot.

Mahesh

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#4 2019-09-23 12:45:27

Sarah
Member
Registered: 2016-08-01
Posts: 40

Re: [SOLVED] Spin-orbit coupling between siglet and triplet states

Ignacio wrote:

I may be mistaken, but I think I1 and I2 are the indices of the states. You have two singlets in JOB001 and three triplets in JOB002, so I'd guess the indices are:

S_0: 1
S_1: 2
T_1: 3, 4, 5
T_2: 6, 7, 8
T_3: 9, 10, 11

S1, S2 are the total spins of the states: 0.0 for singlets, 1.0 for triplets. MS1, MS2 are the m_s quantum numbers of the states: 0 for singlets, -1, 0, -1 for triplets. If you want the couplings between S_1 and T_2, that's between indices 2 and 6,7,8, so:

     6  1.0 -1.0    2  0.0  0.0        -8.626        19.659        21.468
     8  1.0  1.0    2  0.0  0.0        -8.626       -19.659        21.468

but check the energies reported by RASSI to make sure these are the states you want.

Dear Ignacio,

In the above quote, what would be the final coupling between S_1 and T_2? should we sum over the coupling values (2 to 6 and 2 to 7) which makes  42.936 for the SO coupling from S_1 to T_2?

Best,
Sarah

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#5 2019-09-23 13:58:29

Ignacio
Administrator
From: Uppsala
Registered: 2015-11-03
Posts: 1,085

Re: [SOLVED] Spin-orbit coupling between siglet and triplet states

I'd guess the triplet is actually three different states, so it's either the maximum or the average that would make sense...

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#6 2019-10-22 08:11:49

Ofer
Member
Registered: 2019-10-21
Posts: 1

Re: [SOLVED] Spin-orbit coupling between siglet and triplet states

This is a very helpful thread. Thank you for sharing.

Ofer.

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#7 2022-07-08 09:13:01

chipmunk
Member
Registered: 2015-11-12
Posts: 23

Re: [SOLVED] Spin-orbit coupling between siglet and triplet states

Ignacio wrote:

I may be mistaken, but I think I1 and I2 are the indices of the states. You have two singlets in JOB001 and three triplets in JOB002, so I'd guess the indices are:

S_0: 1
S_1: 2
T_1: 3, 4, 5
T_2: 6, 7, 8
T_3: 9, 10, 11

S1, S2 are the total spins of the states: 0.0 for singlets, 1.0 for triplets. MS1, MS2 are the m_s quantum numbers of the states: 0 for singlets, -1, 0, -1 for triplets. If you want the couplings between S_1 and T_2, that's between indices 2 and 6,7,8, so:

     6  1.0 -1.0    2  0.0  0.0        -8.626        19.659        21.468
     8  1.0  1.0    2  0.0  0.0        -8.626       -19.659        21.468

but check the energies reported by RASSI to make sure these are the states you want.


Such a great answer. Very useful to me. Many thanks.

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