Coherent control of electrons in molecules

Abstract

Coherent superposition of electronic states can be achieved by simultaneous laser excitation at different frequencies. As an example, the three-level system is examined in order to demonstrate the possibility of phase control of electron transfer in molecules. Ab initio calculations are used to illustrate the principle in a charge transfer molecule DMBAN, 4-(N,N-dimethylamino)benzonitrile.Key words: laser control, charge transfer electrons. [Traduit par la ridaction]

Attosecond localization of electrons in molecules

“…The study of interactions of intense ultrashort laser pulses with molecules is a relatively new science [4], with the first discovery of nonlinear nonperturbative laser-molecule interaction leading to a new concept, laser-induced molecular potentials (LIMPs)-predicted as early as 1981 [5] and recently confirmed experimentally [6,7]. At the very high intensities now available, I Ն 10 14 W/cm 2 , one now must consider dissociative ionization so that one must deal with bound-continuum transitions both in the electronic and nuclear Hilbert space.…”

“…Thus the combination of large electronic transition moments in symmetric molecules and current high laser intensities result readily in nonperturbative radiation-molecule interactions. Such effects lead to LIMPs [5][6][7] and charge resonant enhanced ionization (CREI), whereby molecular ionization rates can exceed that of atomic fragments by orders of magnitude at large critical internuclear distance R c Ӎ 2R e , where R e is the equilibrium distance [13][14][15]. Quasistatic models of atom-laser field interaction [2] have been extended to nonperturbative laser-molecule interactions with the tunneling ionization of Stark-displaced LUMOs leading to a simple consistent explanation of CREI and CE in molecules for one-or odd-electron molecular systems [13][14][15].…”

Photoionization of Oriented HD(1Σ+) Yields Vibrating HD+(2Σ+) with Charge Breathing and Small Charge Transfer

“…The importance of correlation in coupled electron and nuclear dynamics has, recently, been pointed out in experiments of dissociative photoionization of H 2 and simulations of charge migration in HCCI. + Charge migration is the ultrafast electronic process by which electrons in a molecule oscillate from one site to another even without any significant relative nuclear motion. − Charge transfer is the electronic process by which electrons flow from one nucleus to another in a molecule, for instance, induced by the nuclear motion. − Other mechanisms such as electron–electron collisions, electron–phonon coupling, or coupling of electrons to an environment can also induce charge transfer . Thus, although charge migration may appear only with excitation of molecular electronic states, nuclear motion and therefore rovibrational excitation must be present in intramolecular charge transfer .…”