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Dear multiwfn users and developers,
I noticed some inconsistencies between transition dipole moments computed directly (function 18 -> 5) and from ESP atomic charges. Am I doing something wrong? I do the following:
First, I run a TD-DFT calculation using gaussian16. In this example I consider para-nitroaniline to get the required .fch and .log files
To compute ESP charges i do the following
1) compute ground state ESP charges using function (7 -> 12 -> 5 -> 1)
2) compute excited state ESP charges: generate natural orbitals (18 -> 13) and compute ESP charges using the natural orbitals (7 -> 12 -> 5 -> 1)
3) compute ground-to-excited state TrESP: generate transition density matrix (18 -> 9 -> 1), generate natural orbitals from transition density matrix (200 -> 16 -> SCF), generate TrESP (7 -> 12 -> 5 -> 3)
4) compute excited-to-excited state TrESP: generate transition density matrix (18 -> 9 -> 2), generate natural orbitals from transition density matrix (200 -> 16 -> SCF), generate TrESP (7 -> 12 -> 5 -> 3)
5) dipole moments are computed as \sum_i q_i*r_i where, q_i is the charge on atom i with position r_i
To compute permanent dipole moments and transition dipole moment between all excited states directly, I use function (18 -> 5)
As you can see from the data attached, there is good agreement between dipole moments computed directly and dipole moments computed from ESP charges, except in the case of permanent dipole moment of the excited states. Is this expected? Is there a problem with the procedure I'm using?
attachments:
pna-data.xlsx
Thank you for your time
Dear all,
I want to run ESP fitting imposing constraints so that the final charges reproduce the dipole moment. In principle, this is achievable using charge constraints, adding three constraint (one for each cartesian component of the dipole moment) like this:
\sum_i r_{ij} q_{i} = \mu_{j}
where r_{ij} is the j-th component of the position of the i-th atom, q_i is the charge on i-th atom and \mu_j is the j-th component of the dipole moment.
With reference to chapter 3.9.16.1 of the Multiwfn guide, one would need to add atomic coordinates in matrix A and the dipole moment components in matrix B.
Is this achievable in Multiwfn? Can I input values different from 0 and 1 to matrix A?
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