[gmx-users] electric field amplitude of a photon

[Alex]

Hi all,

Gromacs manual section 6.7 refers to this paper: 
https://onlinelibrary.wiley.com/doi/abs/10.1002/anie.200703987 so I 
guess my question is for David.

What is unclear is how the electric field amplitudes were estimated 
(text below Eq. 1). I mean, we can of course get something like sqrt[ 
I/(eps_0 x c)] (it also seems there might be a typo in the left column 
of p. 1417 of the paper -- there should not be 1/2, if one includes the 
energy of the magnetic field to actually equate the E_0-based value to 
the total intensity).

That possible typo aside, is that where the values of E_0 came from? 
Granted, all of this is very approximate, trying to mimic quantum 
physics with a painfully classical picture, but for consistency and so I 
could properly cite this work if needed, it might be useful to know how 
these values were calculated. My case is non-pulsed, but that's irrelevant.

Thanks!

Alex