VMD-L Mailing List

From: Sadegh Faramarzi Ganjabad (safaramarziganjabad_at_mix.wvu.edu)
Date: Fri Mar 18 2016 - 14:00:43 CDT

Josh,

Thanks. Now it makes sense.

Sadegh

On Tue, Mar 15, 2016 at 11:00 AM, Josh Vermaas <vermaas2_at_illinois.edu>
wrote:

> Hi Sadegh,
>
> You know that VMD by default does everything in Angstroms, right?
> Angstroms make more sense for bond lengths and atom radii than nm, so
> internally everything is stored in Angstroms. Divide by 100 to go from
> Angstroms^2 to nm^2, and you answers line up with what you expect. :)
> -Josh Vermaas
>
> On 03/14/2016 05:43 PM, Sadegh Faramarzi Ganjabad wrote:
>
> Hello all,
>
> I am using 'measure inertia', trying to determine asymmetry parameter of a
> structure from principal moments of inertia (I1, I2 and I3). Following is
> the argument I use on VMD, and the results
>
> measure inertia $sel moments eigenvals
>
> {-3.099947452545166 -14.4624662399292 18.04184913635254}
> {{0.10595881938934326 0.8530250787734985 -0.5109999179840088}
> {-0.24898460507392883 0.520282506942749 0.8168922066688538}
> {0.9626939296722412 0.04067419841885567 0.2675185799598694}} {{3119726.75
> 0.0 0.0} {-8870.5205078125 3985480.75 0.0} {-207580.5 -108537.25
> 3825170.75}} {4049397.5 3819312.5 3061668.25}
>
> I am assuming the last three values (eigenvalues) are the ones I am
> looking for, since they all have positive values. However, the values of
> principal moments of inertia are supposed to be in order of 10 ^ 4
> amu.nm^2, rather than 10 ^ 6. Does anybody know what the units of the
> eigenvalues are?
>
> Thanks
> Sadegh
>
>
>
>