Electronic Stark effect for a single molecule: Theoretical UV response

Abstract Theoretical analysis of optical absorption in the vacuum ultra-violet (VUV) region by single molecules placed in external electrostatic fields reveals characteristic absorption spectra completely at variance with their ‘zero-field’ counterparts consequent to appearance, disappearance, splitting, merging and shifts of absorption bands and extensive intensity redistributions. This ‘molecular electronic Stark effect’ can be tracked through electronic excitations involving frontier orbitals, energy-level splitting and shifts, molecular geometry changes and re-orientation, orbital mutation and migration. The UV spectra predicted herein should provide theoretical grounds for experimental endeavors on appraisal and characterization of the effect.