Hi,

To introduce an electric field in your simulation, use the following:

E_x= 1 3 0 ; First number is the number of cosines, second is the intensity of the field  in V.nm-1. Third number is the phase of the cosine.

You can play now with E_x, E_y, and E_z components and intensity to form the field you want.

Hi,

To introduce an electric field in your simulation, use the following:

E_x= 1 3 0 ; First number is the number of cosines, second is the intensity of the field  in V.nm-1. Third number is the phase of the cosine.

You can play now with E_x, E_y, and E_z components and intensity to form the field you want.

what about E_xt

it means that the electrical field changes  over the time?

how can I fix it ?

Please see these links. 

https://www.mail-archive.com/[email protected]/msg09974.html

https://gerrit.gromacs.org/#/c/4458/

thanks

Hi Mathiue and Rakesh

I followed the instructions, but this is a serious issue.

That's only about two lines in the .mdp file. The strength of the E-field can be set by:

E-x = 1 E0 0

but what about the frequency?

In the link that Rakesh has sent, it has clearly mentioned that the subject is newly documented. The frequency, omega should be set as this:

E-xt = omega t0 sigma

For an E-field of :

E(t) = E0 exp ( -(t-t0)^2/(2 sigma^2) ) cos(omega (t-t0))

The unit of omega should be naturally the inverse of time, or ps^-1. I am interested to simulate water for 200GHz (continuous E-field, no signal), means that omega should be

2 x pi x 200 x 10^9 s^-1 = 1.256 ps^-1. So the line is the mdp file is this:

E-zt = 1.256 0 0

From my experience I know that with the E-fields as big as 0.2 V/A, the overall alignment follows the frequency, but the frequency of the alignment is near 25ps! (which should be 5ps). This clearly shows that the second command does not work. Interestingly changing the omega to other values does not change alignment frequency.

Do you have any suggestion in that? How can I fix this?

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