Physical Chemistry Seminar: Attosecond Science with Polar Molecules

Abstract:

Asymmetric molecules look and react differently when viewed from one side or the other. This difference influences the electronic structure of the valence electrons, thereby giving stereo sensitivity to chemistry and biology. I will show how the attosecond and re-collision science provides a detailed and sensitive probe of electronic asymmetry. I will demonstrate how a high-density gas can be oriented, report the first experimental observation of even and odd harmonics generated from oriented molecular samples and discuss the physical mechanism leading to orientation. The harmonic spectrum encodes three manifestations of asymmetry; an amplitude and phase asymmetry in electron tunneling; an asymmetry in the phase that the electron wave packet accumulates relative to the ion between the moment of ionization and recombination; and an asymmetry in the amplitude and phase of the transition moment.  The sensitivity of the high harmonic spectrum to subtle phase differences will drive major advances in the theory of high harmonic generation and give us detailed insight into the molecule itself.