Hi, I am using neb to calculate activation energy of hydrogen in unit cell of nickel. I have placed hydrogen in octahedral position and I am moving it to another octahedral position as shown below. My question is whether neb can calculates transition state which is tetrahedral site?. I have used a path_thr of 0.01eV with 7 images. I have calculated the activation energy which I am getting is 1.05 eV as shown in output, whereas the experiments indicate 0.42.
*input * FIRST_IMAGE ATOMIC_POSITIONS crystal Ni 0 0 0 Ni 0 0.5 0.5 Ni 0.5 0 0.5 Ni 0.5 0.5 0 H 0.5 0.5 0.5 LAST_IMAGE ATOMIC_POSITIONS crystal Ni 0 0 0 Ni 0 0.5 0.5 Ni 0.5 0 0.5 Ni 0.5 0.5 0 H 0.0 0.5 0.0 END_POSITIONS *output* ------------------------------ iteration 56 ------------------------------ tcpu = 6675.4 self-consistency for image 1 tcpu = 6683.4 self-consistency for image 2 tcpu = 6764.1 self-consistency for image 3 tcpu = 6846.9 self-consistency for image 4 tcpu = 6948.8 self-consistency for image 5 tcpu = 7031.7 self-consistency for image 6 tcpu = 7113.1 self-consistency for image 7 activation energy (->) = 1.024248 eV activation energy (<-) = 1.024248 eV image energy (eV) error (eV/A) frozen 1 -4690.3920838 0.000000 F 2 -4690.3237895 0.006072 F 3 -4689.7348781 0.005158 F 4 -4689.3678358 0.006904 F 5 -4689.7349752 0.004005 F 6 -4690.3237535 0.006484 F 7 -4690.3920838 0.000000 F path length = 5.711 bohr inter-image distance = 0.952 bohr -- Thanks Ravi Research assistant, univ of saskatchewan canada
_______________________________________________ Pw_forum mailing list Pw_forum@pwscf.org http://pwscf.org/mailman/listinfo/pw_forum