Electric field and intensity of the electric field for molecular optical properties

[Jose Javier Plata Ramos]

Dear all,

I have read the paper "Classical Electrodynamics Coupled to Quantum
Mechanics for calculation of Molecular Optical Properties" by Schatz
et al. I would like to reproduce their simulated spectra of N3. In
their article they mentioned that they use a magnitude for the
electric field of 0.002745 V/nm. However in cp2k input you have to use
the  intensity of the electric field (W/cm^2) and the wavelength of
the electric field. I would like to know how I could convert this
value (0.002745 V/nm) to CP2K input values.

Thank you in advance for your help.

Best regards,

Jose