Orbital-selective X-ray solvatochromism in aqueous nitromethane resolved via a dipole-field interaction model.

Solvatochromic shifts in aqueous nitromethane (CH3NO2) are shown to be predominated by dipole-field interaction between the molecular dipole and the solvent field, rather than directed hydrogen bonding. Opposing shifts of π*- and σ*-resonances in X-ray absorption spectra can thus be quantitatively explained through dipole changes upon core-excitation.