[molpro-user] Spin-orbit coupling between Triplet and Singlet states

[Jacky LIEVIN]

Hi Kelvin,

Simply change the tranls command so:   {ci;tranls,4500.1,4600.1,2,0,lsy}
You must specify the values of 2 x MS of the bra and ket functions (2 for the triplet and 0 for the singlet) and the operator you want to calculate.

The calculated value is 8.16 cm-1

best wishes

Jacky


Le 7 mai 2015 à 07:52, Kelvin Lee <kin.lee at unsw.edu.au> a écrit :

> Dear Molpro mailing list,
> 
> 
> 
> I am trying to learn how to calculate the spin-orbit matrix element between a singlet and triplet state. As a starting point, I've been trying to calculate CH2 using CASSCF and MRCI, as there is a lot of published data on this molecule.
> 
> I've tried following the example given in the manual on the S-atom, but the results I'm getting on CH2 make very little sense to me, and I'd appreciate it if anyone would extend their help.
> 
> My input is as follows:
> 
> ***,Calculating spin-orbit coupling of CH2
> memory,148,M
> angstrom
> gthresh,orbital=1.d-8,energy=1.d-8,step=1.d-5,gradient=1.d-5
> nosym
> geom={
> C
> H1 C rCH
> H2 C rCH H1 aHCH
> }
>  RCH=                 1.12276332 ANGSTROM
>  AHCH=              102.15789308 DEGREE
> basis=dzp
> {uhf;occ,5;wf,8,0,2         ! UHF of triplet ground state
> orbital,4400.1
> }
> {multi;occ,10;wf,nelec=8,spin=2;wf,nelec=8,spin=0}
> 
> {ci;wf,nelec=8,spin=2;save,4500.1}        ! triplet wavefunction
> {ci;wf,nelec=8,spin=0;save,4600.1}        ! singlet wavefunction
> 
> {ci;tranls,4500.1,4600.1}                 ! calculate matrix element
> 
> 
> Which, at the end of the output gives me:
> 
>  Spin-orbit matrix elements for mean field operator:
> 
>  !MRCI expec          <1.1|LSZ|1.1>     0.000000000000i au =     0.000000006576i cm-1
> 
> If I'm interpreting this correctly, this is supposed to be my matrix element for these two states?
> The previously calculated values lie around ~12 cm-1 or so, so what unbelievably stupid mistake am I making?
> 
> Any form of help would be greatly appreciated.
> 
> 
> 
> 
> Thank you,
> 
> 
> Kelvin
> 
> 
> -- 
> KIN LONG KELVIN LEE | PhD Student
> Molecular Photonics Group | School of Chemistry | Faculty of Science
> University of New South Wales
> Room 417, Chemical Sciences Building F10 | NSW | AUSTRALIA | 
> 2052
> T 
> 9385-0457 |
> E 
> kin.lee at unsw.edu.au |
> 
>  
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_____________________________________
Prof. Jacky Liévin
Service de Chimie Quantique et Photophysique
Université Libre de Bruxelles, CPi 160/09
50 av F.D. Roosevelt
B-1050 Bruxelles
Belgium
Tel: +32-2-650 4089
Fax: +32-2-650 4232
_____________________________________