From: Josh Vermaas (vermaas2_at_illinois.edu)
Date: Tue Mar 15 2016 - 10:00:00 CDT

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
>
>