Hole burning Stark-effect studies on aromatic aminoacids: I. Phenylalanine in a glycerol–water glass

Abstract

We measured the Stark-effect of spectral holes burnt into the long wavelength absorption of phenylalanine dissolved in a glycerol–water glass. Within the pH-range investigated we observed two protonation–deprotonation transitions, however, they did not change the general pattern of the Stark-effect: phenylalanine behaves as a nearly centrosymmetric molecule with no detectable permanent dipole moment up to a field strength of about 40 kV cm⁻¹.