Dear quantum-ESPRESSO users, I am running some calculations with espresso 5.1 and the van der Waals rVV10 functional.
First, with the program:
generate_rVV10_kernel_table.x
I generated the universal file:
rVV10_kernel_table
Then I tried three systems up to now,
1. two water molecules (insulating)
2. a surface with some organic molecules on top (insulating). This is the
system I am actually interested in.
3. graphite, with some smearing
In the first two cases
the energy seems to reach convergence but then
suddenly the scf accuracy increases , like this
estimated scf accuracy < 0.06260677 Ry
estimated scf accuracy < 0.04294545 Ry
estimated scf accuracy < 0.02031181 Ry
estimated scf accuracy < 0.01888999 Ry
estimated scf accuracy < 0.01019674 Ry
estimated scf accuracy < 0.00222739 Ry
estimated scf accuracy < 0.00317661 Ry
estimated scf accuracy < 0.00370097 Ry
estimated scf accuracy < 0.00396386 Ry
estimated scf accuracy < 0.00018021 Ry
estimated scf accuracy < 1.54950129 Ry
estimated scf accuracy < 1.54973018 Ry
estimated scf accuracy < 1.54679045 Ry
...and so on and does not converge after 100 steps. I tried to reduce the
mixing to 0.1, or even smaller, without any effect. (see attachments)
For the more complex surface+molecules system, the behaviour is similar.
For the graphite with some smearing, the eigenvectors of the Hamiltonian
fail to converge in the diagonalization process. (see attachment)
I would appreciate some help to ascertain if:
1. I am doing something wrong somewhere?
2. there is an issue in the convergence of rVV10 with insulators?
3. is there a (different) issue with rVV10 and smearing?
I am aware that water calculations with rVV10 have been successfully
performed, so I would appreciate very much your suggestions.
Thanks
Best,
Andrea
--
Dr Andrea Floris
Research Associate
King's College London
Strand, London WC2R 2LS
United Kingdom
Phone: +44 (0) 207 848 2064
Fax : +44 (0) 207 848 2420
Location: Strand Building, 4th floor, Room 4.02
Emails: [email protected], [email protected]
out_rVV10_gra
Description: Binary data
inp_rVV10_gra
Description: Binary data
inp_water_rVV10
Description: Binary data
out_water_rVV10
Description: Binary data
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