Fragmentation dynamics of methane induced by femtosecond laser pulses

5^th International Conference and Exhibition on Lasers, Optics & Photonics

November 28-30, 2016 Atlanta, USA

Viviane Costa Felicissimo

Federal University of Sergipe, Brazil

Posters & Accepted Abstracts: J Laser Opt Photonics

Abstract :

The conversion of methane to value-added chemical products such as alcohols, aldehydes and higher alkanes is one of the greatest challenges of these last years. Methane is the most inert of hydrocarbons and the principal constituent of the natural gas. It has been verified that the vibrational excitation of methane can play an important role in activating this inert molecule. In the last years, significant progress has been made by Richard N Zare and co-workers toward understanding of the role of vibrations in the chemical reactions with methane. The interest of promoting infrared (IR) excitation in resonance with a selected vibrational and the rapid advances in the technology of femtosecond pulsed laser have stimulated an increasing number of studies about the fragmentation of methane induced by ultra-short laser pulses. The efficiency of using femtosecond laser pulses to guide and follow the nuclear motion, breaking or forming selected bonds during a chemical reaction has been studied for many years. The first to use femtosecond laser technology to solve problems in chemistry and biology was Ahmed H Zewail in the mid-80s. With the interaction of high intensity (~1012-1014 W/cm2) femtosecond laser pulses, molecules can undergo a variety of dynamical processes, in which neutral fragmentation can occur. In the present work, we investigate theoretically, through ab-initio molecular dynamics simulations, the chemical reaction of dissociation of methane induced by intense femtosecond IR pulses. An alternative mechanism based on the rectification of the electric force, demonstrated at first by Faris Gel�mukhanov et al, is employed to explain the neutral fragmentation of C-H bond in methane. A strong IR laser field induces a periodical charge transfer between different parts of the molecule, resulting in the rectification of the Lorentz force. This creates the opportunity to produce a direct mechanical action of the light on atoms or group of atoms in the molecule.

Biography :

Email: felicissimo@ufs.br