The Hydrogen molecular cation as a molecular antenna

Abstract

We study how the molecular hydrogen cation reacts to strong nonresonant fields, creating dipoles that oscillate at the driving carrier frequency. These dipoles are analogs of molecular antennas. The results are obtained by solving the time-dependent Schrödinger equation with simplified Hamiltonian models, assuming molecular orientation. Starting from the ground electronic state, we show under what conditions an optical molecular antenna is created and analyze its magnitude and the physical processes that lead to its disruption. Starting from the first excited electronic state we show how to generate a much larger (but unstable) far-infrared antenna that can only be created by a very intense field of specific frequency.

Molecular events in the light of strong fields: A light‐induced potential scenario

“…For lower frequencies the excursion length and the induced dipole could be larger, but tunneling ionization dominates. [99] In summary, we have shown that in order to create an oscillating electric dipole in a homonuclear diatomic cation without an oscillating driver one needs (i) to break the symmetry of the system and (ii) to sustain highly correlated electronic and nuclear motion, which are guaranteed by the LAMB dynamics.…”

“…Here, we analyze the role of the electronic wave function and of electron-nuclear dynamics. [96,98,99] In a LAMB process, the total wave function of the system is a coherent superposition of both nuclear and electronic wave functions, [86] WðR; q; tÞ5/ g ðR; tÞN g ðq; RÞ1/ e ðR; tÞN e ðq; RÞ…”

“…In order to analyze the type of electron changes conveyed by the transformation of the LIP and the possible effects of electron-nuclear motion, one needs to use a model that allows integrating the full time-dependent Schr€ odinger equation beyond the Born-Oppenheimer approximation. In the following, we use a well-known 1 1 1D Hamiltonian often employed to characterize the dynamics of the molecular Hydrogen cation under strong fields, [96][97][98][99] H52 h 2 2l e…”

“…[99] In particular, its frequency must be approximately equal to the frequency of the vibrational motion in the LIP. Otherwise, the correlation between the motion of the electron driven by the field, and that of the protons, oscillating in the potential, is not perfect.…”

“…In correspondence to the geometrical changes induced by the LIP, there are changes in the electronic properties associated to the electronic superposition state. [96][97][98][99] These properties, for example the permanent or transition dipole, reflect the underlying changes in the redistribution of charges. It was recently shown that some superpositions manifested a clear classical picture of an electron oscillating between the protons, whereas in a dressed electronic state the electron was moving along with the proton.…”