BigDFT

Optimizing the structure in gas phase and Solvent

Asked by Asif Iqbal

Dear Developers,

In the manual, it is stated for isolated system the parameters to look for convergence is "frac_fluct" and for crystal structure "fmax". What is the best option for simulating molecule in gas phase. Should convergence be checked with respect to "frac_fluct" but that leads expensive calculation and some time it just get stuck. What is the correct way.

Regarding Solvent, is there any implementation of COSMO or PCM model.

Regards,
Asif

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Luigi Genovese (luigi-genovese) said : 		#1

The value of frac_fluct should _not_ be reduced to get a converged calculation. Otherwise the criterion is too stringent and of course the code get stuck.
Just leave frac_fluct to order 1.0 or similar (say 0.5) and reduce maxval instead.
If you cannot get the desired maxval tolerance, then your basis set is too coarse or your gnrmv_cv too high.

Take care

Luigi

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Asif Iqbal (bhatti-asif-iqbal) said : 		#2

Thanks Luigi Genovese, that solved my question.

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Asif Iqbal (bhatti-asif-iqbal) said : 		#3

Just to clarify maxval parameter is the same as forcemax. and gnrm_cv is the default value.

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Launchpad Janitor (janitor) said : 		#4

This question was expired because it remained in the 'Open' state without activity for the last 15 days.

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Luigi Genovese (luigi-genovese) said : 		#5

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