[CPMD-list] More on NOSE Electrons..

[Dave Sherman]

Thank you, Christl, for pointing out the Blochl and Parrinello (1992, 
PRB, 45:9413) paper to me.

As I understand it, for the long simulations I'm trying (~ 5 ps), I 
certainly want to thermostat the fictitious kinetic
energy of the electronic wavefunctions.  Blochl and Parrinello point 
out that periodic quenching to the BO surface will screw up the 
dynamics unless you do it at every timestep.

In equation 6 of the Blochl and Parrinello (1992; PRB) paper, they 
suggest  the target fictitious kinetic energy of the electronic wave 
functions to be

		2kbT(mu/M) SUM<psi |-1/2del2 | psi>

where, as I see it, the summation (SUM<psi |-1/2del2 | psi>) is simply 
the total real electronic kinetic energy in the ground state (in A.U), 
mu is the fictitious mass of the wavefunction, and M is the mass of one 
atom.    However, since kbT has units of energy, then the whole 
expression  has units of energy**2.  This can't be right; is there a 
typo or am  I confused about something..?

Thanks for your help!

Dave Sherman
______________
David M. Sherman
Professor of Geochemistry
Department of Earth Sciences
University of Bristol
Bristol BS8 1RJ UNITED KINGDOM
Phone: 44-(0)117-954-5446
http://mineral.gly.bris.ac.uk