[Pw_forum] NEB "spring constants"

[Vic Bermudez]

Hello,

	Can someone please explain the criteria for the proper choice of "k_min" and "k_max" in
NEB calculations ? The default choice in QE 4.3.2 is k_min = k_max = 0.2 a.u.. However,
when I run NEB job, the start-up information near the beginning of the output file says:

     suggested k_max               =  0.6169 a.u.
     suggested k_min               =  0.6169 a.u.

I've been using the suggested values, rather than the defaults, and I'm wondering how
sensitive the calculation is to this choice and also how one goes about deciding the best
choice.
	As always, thank you in advance for your assistance

************
Victor M. Bermudez
Code 6876
U.S. Naval Research Laboratory
4555 Overlook Ave., S.W.
Washington, DC 20375-5347

Phone: 202-767-6728
FAX: 202-767-1165
E-mail: victor.bermudez at nrl.navy.mil