chemical bond in excited states using Multiwfn and Orca

rikaaardoss · 2022-03-26 08:39:55

Hi all, I am interested in analyzing chemical bonding in excited states using Multiwfn. For this I have done casscf calculations in ORCA, the system I am studying is triplet in its ground state (T0), however I am not getting the wave function of the first triplet excited state (T1), is there any way to obtain this function?, here is the input I am using:

! def2-TZVP def2/J
! moread
%moinp "c2o_t.gbw"
%MaxCore 20000
%scf
TolG 1.0e-04
TolE 1.0e-06
maxiter 500
end
%casscf
nel 14
norb 10
mult 3
nroots 3
weights[1] = 1.0,0.0,0.0
end

%pal nprocs 10
end
*xyz 0 3
C 0.000000000 0.000000000 0.000000000
C 0.000000000 -1.369900105 0.000000000
O 0.000000000 1.162700089 0.000000000

I figured I should change the weight of the state, so I would have this: " weights[1] = 0.0,1.0,0.0 "

However, when I get the molden file and check the occupancies of the natural orbitals both files are very similar.

Thanks advance for any help provided.

R.

sobereva · 2022-03-26 08:50:57

Usually, to calculate excited state by CASSCF, you should use state-average treatment, otherwise due to variational collapse, despite you set initial weight of T1 as 1.0, the wavefunction may finally converge to T0.

rikaaardoss · 2022-03-26 08:58:24

So, from what I understand, there is no way to obtain the wave function of the system in the excited state T1, but I could only study it in T0.

sobereva · 2022-03-26 10:05:37

rikaaardoss wrote:

So, from what I understand, there is no way to obtain the wave function of the system in the excited state T1, but I could only study it in T0.

You should set both first and second states with weight of 0.5. Then both the states should be able to solve.

Multiwfn forum

#1 2022-03-26 08:39:55

chemical bond in excited states using Multiwfn and Orca

#2 2022-03-26 08:50:57

Re: chemical bond in excited states using Multiwfn and Orca

#3 2022-03-26 08:58:24

Re: chemical bond in excited states using Multiwfn and Orca

#4 2022-03-26 10:05:37

Re: chemical bond in excited states using Multiwfn and Orca

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