DFT-NEB calculation stops give error


Just Got Here
Dear Users,

I am performing DFT-NEB simulation to determine the energy barrier to get Ethylene (CH2O) from
Epoxide (C2H4O). The simulation stops giving the following errors.

ga_iter_lsolve: convergence stagnant ... aborting solve
run_bead_list failed

My input script is pasted below.

title "Epoxide-Ammonia rearrangement - NEB calculations"

start neb-epoxide-to-c2h2

basis
 * library 6-311++G**
end

dft
  xc b3lyp
maxiter 5000
cgmin
end

        1. define the start geometry ####
geometry units angstroms print xyz nocenter noautosym
C 41.07133 39.31130 39.53571
C 39.59843 39.09966 39.40598
H 38.95348 39.89523 38.96658
O 40.21069 39.33475 40.66907
H 39.22178 38.07862 39.19536
H 41.76839 38.44702 39.44947
H 41.50319 40.28287 39.20693
end

        1. define the end geometry ####
geometry endgeom units angstroms print xyz nocenter noautosym
C 44.07133 39.31130 39.53571
C 39.59843 39.09966 39.40598
H 38.95348 39.89523 38.96658
O 40.21069 39.33475 40.66907
H 39.22178 38.07862 39.19536
H 44.76839 38.44702 39.44947
H 44.50319 40.28287 39.20693
end

neb
  maxiter 1000
nbeads 20
stepsize 0.10
kbeads 0.1
end
task dft neb ignore

I will appreciate your suggestion to overcome this problem.

Thank you.
Kind regards,
Sanjib


Forum >> NWChem's corner >> General Topics