A Laser-Based Instrument for the Study of Ultrafast Chemical Dynamics by Soft X-ray-Probe Photoelectron Spectroscopy

Published

April 1, 2002

Author(s)

L Nugent-Glandorf, M Scheer, D A. Samuels, V M. Bierbaum, S R. Leone

Abstract

A laser-based instrument is described for the study of femtosecond dissociation dynamics of gas phase molecules via time-resolved vacuum ultraviolet and soft x-ray photoelectron spectroscopy. Visible or UV pump pulses are generated with nonlinear crystal techniques on a Ti:sapphire laser output, while soft x-ray probe pulses are created via high-order harmonic generation of the same laser in rare gases. Here we describe the optical layout of the pump-probe system, the means for separation of the high-order harmonics in the soft x-ray probe beam,including a description of the two grating set up used to compress the high harmonic pulses and the magnetic bottle photoelectron spectrometerused for data collection. The feasibility of using the generated high-harmonic pulses for an array of gaseous phase photoelectron spectroscopyexperiments is established. These include measurements of valence shell and core level photoelectron transitions in atoms and molecules, thetunability of the soft x-ray harmonic through Rydberg resonances, and the energy bandwidths of the harmonics. Cross-correlations between the visible/UV andsoft x-ray pulses, by above threshold ionization, are used to establish the pulse timing, pulse duration, and spatial overlap for ultrafast studies. The observed real time photodissociation of Br₂ serves as a demonstration of the pump-probe ultrafast technique and the applicability to ultrafast time-resolved chemical dynamics.

Citation

Review of Scientific Instruments

Volume

73

Issue

No. 4

Pub Type

Journals

Keywords

photoelectron, pump-probe, soft x-ray

Citation

Nugent-Glandorf, L. , Scheer, M. , Samuels, D. , Bierbaum, V. and Leone, S. (2002), A Laser-Based Instrument for the Study of Ultrafast Chemical Dynamics by Soft X-ray-Probe Photoelectron Spectroscopy, Review of Scientific Instruments (Accessed October 12, 2024)