Convergence problem with tiny molecule

From NWChem

You are viewing a single post from the thread title above
Jump to: navigation, search

Click here for full thread
Forum Vet
Threads 7
Posts 1355
The convergence problems you are facing are due to broken symmetry issue. What make things worse is that NWChem fails to detect the Td symmetry present in your molecule.
Here is a modified input that will get to convergence. The main changes are
1) Molecule rotated to make NWChem detect the Td symmetry
2) molecular orbital swap to prevent symmetry breaking

start molecule

title "Base test for TiN"

charge 0

geometry units angstroms print xyz
 N         1.02650   1.02650  -1.02650
Ti         1.02650   1.02650   1.02650
 N         1.02650  -1.02650   1.02650
Ti         1.02650  -1.02650  -1.02650
Ti        -1.02650   1.02650  -1.02650
 N        -1.02650   1.02650   1.02650
Ti        -1.02650  -1.02650   1.02650
 N        -1.02650  -1.02650  -1.02650
end

basis
 * library 6-31G*
end
scf
vectors input atomic swap 63 58
end

task scf optimize


Who's here now Members 0 Guests 0 Bots/Crawler 0


AWC's: 2.5.10 MediaWiki - Stand Alone Forum Extension
Forum theme style by: AWC