problem with initial path in neb calculation


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Starting a neb calculation with TWO points ( start and end) is OK. However starting with TREE points gives an initial path with is wrong. Along the path the molecule collapses towards the geometric centre, this a the middle point, and start to expand towards a normal molecule but which is not the endpoint. I could verify that with the test in /nwchem-6.6/QA/tests/ch4_zts. If you the test with the spline method this is ok, the same test with NEB is wrong.
  1. Now with a TS guess


geometry geometry nocenter
 symmetry c1
C 0.000000 0.000000 0.000000
H 0.000000 0.000000 1.089000
H 1.026719 0.000000 -0.363000
H -0.513360 -0.889165 -0.363000
H -0.513360 0.889165 -0.363000
end

geometry endgeom nocenter
 symmetry c1
C 0.000000 0.000000 0.000000
H 0.000000 0.000000 -1.089000
H 1.026719 0.000000 0.363000
H -0.513360 -0.889165 0.363000
H -0.513360 0.889165 0.363000
end

geometry midgeom nocenter
 symmetry c1
C 0.000000 0.000000 0.000000
H 0.000000 1.000000 0.000000
H 1.026719 0.000000 0.000000
H -0.513360 -0.889165 0.000000
H -0.513360 0.889165 0.000000
end

basis
 * library STO-3G
end

  1. print low

neb
print
kbeads 0.001
stepsize 0.2
nbeads 11
maxiter 2
hasmiddle
impose
end

task neb scf


Could you help?
thank you very much
jean-louis