[gmx-users] Problem of Kinetic Energy

[Mark Abraham]

On 3/08/2011 3:25 PM, Size Zheng wrote:
> Hi, there,
>
> I simulate a simple system of pure water with rigid TIP4P model in NVT at 273K.
>
> Why the total kinetic energy, reported from g_energy, is not equal to
> the sum of the rotational kinetic energy and the translational kinetic
> energy, which are obtained from g_traj with options of -ekt and -ekr.

Read g_traj -h. The -ekt and -ekr options do not operate on atoms.

>
> Even though I normalize the total kinetic energy (reported from g_energy)
> with molecular number, its value is still not equal to the sum of the
> rotational and translational kinetic energy ,obtained from g_traj
> with options of -ekt and -ekr.

A stationary swarm of bees has high KE, and yet the swarm has low 
rotational and translational KE.

Mark