[gmx-users] Distribution of water polarization

[Justin Lemkul]

On 5/11/18 11:29 AM, rose rahmani wrote:
> On Fri, 11 May 2018, 19:38 Justin Lemkul, <jalemkul at vt.edu> wrote:
>
>>
>> On 5/11/18 11:06 AM, rose rahmani wrote:
>>> Hi,
>>>
>>> How can i calculate the distribution of water polarization for example
>> for
>>> the first two layers of water at the solid surface?
>>>
>>> How about the number of water molecules with a given polarization?
>>>
>>> I mean exactly figure2 of this article.
>>> Can gmx dipoles do it?
>> Did you do a polarizable simulation?
>>
> No, it is sth like calculating the distribution of polarization (dipole) in
> different dimensions separately. Sth like different orientation of water
> molecules which cause to different orientations of dipoles in different
> dimensions. (Hope to explain clearly, if it's possible please take a look
> at the article)

There is no article, nothing linked, but in any case I'm not going to 
have time to look into it.

If you've done a classical, nonpolarizable MD simulation, you can make 
no claims about polarization. You could compute properties related to 
water molecule orientation (e.g. gmx hydorder), which will tell you 
about the dipole moment orientation in the context of a fixed triangle 
of charges, but that's all you're going to get from simulations like 
these. FWIW, in reality, the dipole moment of the water molecules will 
not be exactly related to these fixed geometries, so this is a weak 
comparison, in my mind.

-Justin

-- 
==================================================

Justin A. Lemkul, Ph.D.
Assistant Professor
Virginia Tech Department of Biochemistry

303 Engel Hall
340 West Campus Dr.
Blacksburg, VA 24061

jalemkul at vt.edu | (540) 231-3129
http://www.thelemkullab.com

==================================================