LAMMPS WWW Site - LAMMPS Documentation - LAMMPS Mailing List Archives
Re: [lammps-users] Angular velocities in principal axes frame
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [lammps-users] Angular velocities in principal axes frame


From: Giacomo Fiorin <giacomo.fiorin@...24...>
Date: Sun, 15 Apr 2018 13:39:45 -0400

Can you clarify what you mean by "principal axes frame"?

If you define a rotating frame of reference that is always aligned with the principal axes of a rigid molecule, the angular velocity of the molecule should be zero in that frame by definition.

Giacomo

On Sat, Apr 14, 2018 at 12:43 PM, Maurice de Koning <dekoning@...527...> wrote:
I’m interested in computing so-called rotational diffusion constants for rigid water molecules (say TIP4P, using shake to maintain the constraints).
One of the definitions for the rotational mean-squared displacement requires access to
molecular angular velocities expressed in the instantaneous principal axes frame. Searching
in the manual it seems that such angular velocities are available only with respect to the simulation
box frame directions. On the other hand, I’ve seen that for certain calculations (body particles), lammps
does compute the principal axes internally.

Would you have any suggestions as to how to compute angular velocities in the principal axes frame?

Thanks!

Maurice


------------------------------------------------------------------------------
Check out the vibrant tech community on one of the world's most
engaging tech sites, Slashdot.org! http://sdm.link/slashdot
_______________________________________________
lammps-users mailing list
lammps-users@...6297....sourceforge.net
https://lists.sourceforge.net/lists/listinfo/lammps-users



--
Giacomo Fiorin
Associate Professor of Research, Temple University, Philadelphia, PA
Contractor, National Institutes of Health, Bethesda, MD