Intense Laser Alignment As a Route to Control of Surface Reactions

Abstract

We explore the possibility of controlling the orientation of adsorbates, and their adsorption site, through alignment of a beam of gas-phase molecules prior to the surface reaction. To that end, we carry out classical trajectory simulations using ab initio data for the specific example of the I(2)/Si(100) adsorption reaction. I(2) is found to adsorb with the molecular axis roughly parallel to the surface plane independently of the initial alignment. The orientation of the molecule in the surface plane and the adsorption site are controllable through alignment of the gas-phase projectiles. Our results are explained in terms of the surface properties and the reaction dynamics, and the extent to which and way in which they may be generalized is discussed.

Directional spinning of molecules with sequences of femtosecond pulses

“…Numerous applications of rotational control in molecular systems include control of chemical reactions [2], deflection of neutral molecules by external fields [11][12][13], high-order-harmonic generation [14,15], and control of molecular collisions with atoms [16] and surfaces [17][18][19][20][21]. Alignment of molecular axes has been implemented with transform-limited and shaped laser pulses using various approaches (see, e.g., [1,2,[22][23][24][25]).…”

Dynamics of polar polarizable rotors acted upon by unipolar electromagnetic pulses: From the sudden to the adiabatic regime

“…In what follows, we assume the system to be initially in one of the stationary states of its field free Hamiltonian, i.e., ψ(θ, φ, 0) = Y M 0 J 0 (θ, φ), with Y M 0 J 0 (θ, φ) a spherical harmonic pertaining to initial quantum numbers J 0 and M 0 . 2 We also choose these eigenstates as a 1 2J + 1 (13) Further below, we will discuss the properties of these analytic sudden-limit wavefunctions and the expectation values obtained from them. But first, we consider explicitly the analytic wavefunctions in the sudden limit for the purely orienting and purely aligning interactions.…”

“…Understanding the dynamics of quantum systems subject to strong time-dependent electromagnetic fields has been central to research areas ranging from molecular [1][2][3][4] to ultrafast laser physics [5,6] and from stochastic [7] to condensed-matter physics [8,9]. In particular, the study of the effects on atoms and molecules of ultra-short ( picosecond) laser pulses and the kicks, whether single or multiple, they exert has matured into a broad field of research with a plethora of applications in science and technology, cf., e.g., Refs.…”

Modifying molecule-surface scattering by ultrashort laser pulses

“…In particular, the effect of molecular orientation by a static electric hexapole field on the scattering process was investigated in detail [27]. Laser control of the gas-surface scattering was achieved using multiphoton ionization of the impinging molecules by long laser pulses of variable polarization [28], and the possibility of controlling molecular adsorption on solid surfaces using ultrashort laser pulses was discussed [29].…”