Share Email Print
cover

Proceedings Paper

Tomography of the molecular quantum state by time-resolved electron diffraction
Author(s): Anatoli A. Ischenko; Lothar Schaefer; John D. Ewbank
Format Member Price Non-Member Price
PDF $17.00 $21.00

Paper Abstract

A procedure is described that can be used to reconstruct the quantum state of a molecular ensemble from time-averaged position probability density functions determined by time- resolved electron diffraction (TRED). The procedure makes use of established techniques for evaluating the density matrix and the phase space joint probability density; i.e., the Wigner function. A novel expression for describing electron diffraction intensities in terms of the Wigner function is presented. An approximate variant of the method, neglecting the off-diagonal elements of the density matrix, was tested by analyzing gas electron diffraction data for N2 in a Boltzmann distribution, and TRED data obtained from the 193 nm photodissociation of CS2 to carbon monosulfide, CS, at 20, 40, and 120 ns after irradiation. Although the diagonal density matrix elements do not define completely the quantum state of a system, nonetheless, the approximate Wigner functions derived from them display the expected features of a Gaussian-like function in the case of N2; and, in the case of CS, they are in agreement with other investigations, indicating collision-less vibrational energy transfer mechanisms for nascent CS during the first 20 ns, and collision-induced electronic S(1DJ) to vibrational CS(X1(Sigma) g+) energy transfer.

Paper Details

Date Published: 22 June 1999
PDF: 16 pages
Proc. SPIE 3516, 23rd International Congress on High-Speed Photography and Photonics, (22 June 1999); doi: 10.1117/12.350538
Show Author Affiliations
Anatoli A. Ischenko, Moscow State Univ. (Russia)
Lothar Schaefer, Univ. of Arkansas (United States)
John D. Ewbank, Univ. of Arkansas (United States)


Published in SPIE Proceedings Vol. 3516:
23rd International Congress on High-Speed Photography and Photonics
Valentina P. Degtyareva; Mikhail A. Monastyrski; Mikhail Ya. Schelev; Alexander V. Smirnov, Editor(s)

© SPIE. Terms of Use
Back to Top