Subject: Molecular Dynamics with mixed Quantum/Classical Forcefield

From: [email-masked] (Howard Alper)
Date: Fri, 15 Nov 1996 18:41:16 -0800

Hi all,

  I will be doing simulations using the mixed or combined quantum/classical
forcefield in CHARMM.  I have several questions, and would appreciate your
help:

1) Does anyone know of improvements in combined-forcefield codes as
regards efficiency?  I am asking because I may designate a non-insigificant
number of atoms as quantum atoms, and so the CPU time will go up drastically.

2) Does anyone know how the CPU time/md step changes as a function of the
number of atoms designated as quantum atoms?

3) Is there any information on the relative amounts of time spent on
calculating the interactions between quantum atoms, vs. the time spent
on interactions between quantum and classical atoms?

  I will summarize the results and post to the list.  Thanks.

  Howard

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