WIsh you have a good day everyone.
I am trying to calculate for the spinorbit coupling constant, but I have got a problem. Eventhough the calculation finished without any error, but the result of SOC value between 2 times of calculation is different between each other. Firstly, I checked the input file (mol. and dal. file) and I am sure that it is correct. So I checked the output file and then I always see the warning is: RSPCTL WARNINGMAXIMUM NUMBER OF MICROITERATIONS, 60. So now I am trying to add into dal. file: .MAX MICRO ITERATIONS and increase it into 200. Will this fix my problem? I attached 2 output file and also the new dal.file with my thinking. Please let me know your idea.
Thank you so much
RSPCTL WARNINGMAXIMUM NUMBER OF MICROITERATIONS

 Posts: 31
 Joined: 04 Sep 2019, 07:51
 First name(s): Hieu
 Middle name(s): Dinh
 Last name(s): Nguyen
 Affiliation: Kunsan Univ
 Country: Korea, Republic of
RSPCTL WARNINGMAXIMUM NUMBER OF MICROITERATIONS
 Attachments

 SPINORBIT_rsplrso_AMFI_quadratic_autosymmetry_MAXMICROITERATIONS.dal
 (441 Bytes) Downloaded 79 times

 SPINORBIT_rsplrso_AMFI_quadratic_autosymmetry_SOC_BDELA.out
 (404.05 KiB) Downloaded 95 times

 SPINORBIT_rsplrso_AMFI_quadratic_autosymmetry_2_SOC_BDELA.out
 (450.68 KiB) Downloaded 81 times

 Posts: 371
 Joined: 27 Jun 2013, 18:44
 First name(s): Hans Jørgen
 Middle name(s): Aagaard
 Last name(s): Jensen
 Affiliation: Universith of Southern Denmark
 Country: Denmark
Re: RSPCTL WARNINGMAXIMUM NUMBER OF MICROITERATIONS
Your spinorbit coupling constants are garbage, because your calculation is triplet unstable (complex eigenvalues in the calculation of lowest triplet excitation). The differences between the two calculations are caused by numerical noise because of the nonconvergence.
Either your DFT iterations do not converge to the ground state (do you get same total energy if you try with another program?), or B3LYP is a bad model for this case.
By the way, your ".MAX IT" keyword has no effect because the ".MAX IT" in that place specify the max. number of geometry iterations in a geometry optimization. But it does not help to increase the correct max iterations for response, because the convergence is stuck because of the above mentioned problems.
Either your DFT iterations do not converge to the ground state (do you get same total energy if you try with another program?), or B3LYP is a bad model for this case.
By the way, your ".MAX IT" keyword has no effect because the ".MAX IT" in that place specify the max. number of geometry iterations in a geometry optimization. But it does not help to increase the correct max iterations for response, because the convergence is stuck because of the above mentioned problems.

 Posts: 31
 Joined: 04 Sep 2019, 07:51
 First name(s): Hieu
 Middle name(s): Dinh
 Last name(s): Nguyen
 Affiliation: Kunsan Univ
 Country: Korea, Republic of
Re: RSPCTL WARNINGMAXIMUM NUMBER OF MICROITERATIONS
Thank you Dr. Hans for your reply. I am sorry but may I ask you a question: Do you mean the SCF energy which was shown in the output file is total energy? And I am thinking to try with another program like molpro to confirm it. I will try to change to MCSCF to see how it works.hjaaj wrote: ↑23 Oct 2019, 13:55Your spinorbit coupling constants are garbage, because your calculation is triplet unstable (complex eigenvalues in the calculation of lowest triplet excitation). The differences between the two calculations are caused by numerical noise because of the nonconvergence.
Either your DFT iterations do not converge to the ground state (do you get same total energy if you try with another program?), or B3LYP is a bad model for this case.
By the way, your ".MAX IT" keyword has no effect because the ".MAX IT" in that place specify the max. number of geometry iterations in a geometry optimization. But it does not help to increase the correct max iterations for response, because the convergence is stuck because of the above mentioned problems.

 Posts: 371
 Joined: 27 Jun 2013, 18:44
 First name(s): Hans Jørgen
 Middle name(s): Aagaard
 Last name(s): Jensen
 Affiliation: Universith of Southern Denmark
 Country: Denmark
Re: RSPCTL WARNINGMAXIMUM NUMBER OF MICROITERATIONS
I mean this final energy:
and these final HOMOLUMO energies:
Note that the HOMO and LUMO orbital energies are very close, so no wonder there is triplet instability.
Code: Select all
@ Final DFT energy: 2824.469146640524
Code: Select all
E(LUMO) : 0.13437205 au (symmetry 1)
 E(HOMO) : 0.14494639 au (symmetry 1)

gap : 0.01057434 au

 Posts: 31
 Joined: 04 Sep 2019, 07:51
 First name(s): Hieu
 Middle name(s): Dinh
 Last name(s): Nguyen
 Affiliation: Kunsan Univ
 Country: Korea, Republic of
Re: RSPCTL WARNINGMAXIMUM NUMBER OF MICROITERATIONS
Maybe I will try to recalculate with gaussian 09 software with same basis set B3LYP/631G* in dal.file to confirm the DFT energy and HOMOLUMO energies.hjaaj wrote: ↑23 Oct 2019, 15:23I mean this final energy:and these final HOMOLUMO energies:Code: Select all
@ Final DFT energy: 2824.469146640524
Note that the HOMO and LUMO orbital energies are very close, so no wonder there is triplet instability.Code: Select all
E(LUMO) : 0.13437205 au (symmetry 1)  E(HOMO) : 0.14494639 au (symmetry 1)  gap : 0.01057434 au
I will keep updating the result.
Thank you so much Dr. Hans
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