Problems with calculation of the excited states in NEVPT2 method.

[Supriyo Santra]

Dear Molpro users, 

     

I am trying to calculate the excited states using NEVPT2  method. As said in the manual, I am doing the CASSCF calculation first, follwed by NEVPT2 calculation. I need to do the NEVPT2 calculation for 3 states, (the ground state and other two excited states) all of which are having the same Ag symmetry. 

 For the ground state the calculation is running fine, but for the next excited state, while starting the NEVPT2 calculation, it is getting printed in the output file that orbital record not found. Also for the second state there is no change in the CASSCF result from the first state. I believe I am making some error in the input description of the excited states. 

I am attaching the part of the input file, here. Kindly help with your suggestions, and please point out the mistake I am making.

Part of input file

===================

basis = 6-311++g(d,p)

{hf

wf,72,1,0}

{casscf

occ,16,5,15,5

closed,16,0,15,0

wf,72,1,0

state,1

natorb,2140.2,state=1.1

}

{nevpt2,thrden=1.0d-10,thrvar=1.0d-10

closed,16,0,15,0

occ,16,5,15,5

orbit,2140.2,state=1.1

wf,72,1,0

state,1,1

}

{casscf

occ,16,5,15,5

closed,16,0,15,0

wf,72,1,0

state,1

start,2100.2

natorb,2141.2,state=2.1

}

{nevpt2,thrden=1.0d-10,thrvar=1.0d-10

closed,16,0,15,0

occ,16,5,15,5

orbit,2141.2,state=2.1

wf,72,1,0

state,1,1

}

  

[Jacky LIEVIN]

Dear Supriyo,

The mistake is that for calculating the second state of Ag symmetry (2.1) you must perform a state averaged CASSCF calculation on the 2 low-lying Ag states:

{casscf

occ,16,5,15,5

closed,16,0,15,0

wf,72,1,0

state,2

natorb,2141.2,state=2.1

}

 

and then start the NEVPT2 calculation on 2.1 using the natural orbitals of this state saved on record 2141.2

{nevpt2,thrden=1.0d-10,thrvar=1.0d-10

closed,16,0,15,0

occ,16,5,15,5

orbit,2141.2,state=2.1

wf,72,1,0

state,1,2

}

Please note that « state,1,2 »  means that the calculated state is the second reference CASSCF state (2.1)

Best wishes,

Jacky

--
You received this message because you are subscribed to the Google Groups "molpro-user" group.
To unsubscribe from this group and stop receiving emails from it, send an email to molpro-user...@googlegroups.com.
To view this discussion on the web, visit https://groups.google.com/d/msgid/molpro-user/ec704eb7-643c-4115-8bac-5ef3773472c6n%40googlegroups.com.