Updated documentation for electric fields.

[alexxy/gromacs.git] / docs / user-guide / mdp-options.rst

diff --git a/docs/user-guide/mdp-options.rst b/docs/user-guide/mdp-options.rst
index 5129754f26ec07eddb69fdcee5771ba24baa3052..86fdfef6105a8ce74ef67ae216e13002d17a4dc8 100644 (file)
--- a/docs/user-guide/mdp-options.rst
+++ b/docs/user-guide/mdp-options.rst
@@ -2544,7 +2544,25 @@ Electric fields
 
 .. mdp:: E-xt; E-yt; E-zt:
 
-   not implemented yet
+   Here you can specify a pulsed alternating electric field. The field
+   has the form of a gaussian laser pulse:
+
+   E(t) = E0 exp ( -(t-t0)^2/(2 sigma^2) ) cos(omega (t-t0))
+
+   For example, the four parameters for direction x are set in the
+   three fields of :mdp:`E-x` and :mdp:`E-xt` like
+
+   E-x  = 1 E0 0
+
+   E-xt = omega t0 sigma
+
+   In the special case that sigma = 0, the exponential term is omitted
+   and only the cosine term is used.
+
+   More details in Carl Caleman and David van der Spoel: Picosecond
+   Melting of Ice by an Infrared Laser Pulse - A Simulation Study
+   Angew. Chem. Intl. Ed. 47 pp. 14 17-1420 (2008)
+
 
 
 Mixed quantum/classical molecular dynamics