Time-Resolved X-ray Absorption Spectroscopy of Carbon Monoxide-Myoglobin Recombination After Laser Photolysis

Abstract

Results are presented for the first time-resolved x-ray absorption measurements with a time resolution of 300 microseconds on a dynamically evolving chemical system. By synchronizing a neodymium: yttrium-aluminum-garnet pulsed laser with the bursts of x-rays emitted from the Cornell High Energy Synchrotron Source, it was possible to monitor at room temperature the recombination of carbon monoxide with myoglobin after laser photolysis. Changes in the pre-edge structure and in the position of the iron edge of this protein were detected as a function of time.

Synchrotron ultrafast techniques for photoactive transition metal complexes

“…In a pioneering experiment, Mills and co-workers probed the reversible photodissociation of a CO group from carboxymioglobin via TR-XANES at the Fe K-edge [140,[234][235][236]. Similar studies on related systems were reported by Clozza et al [237] and by Chance and co-workers [141,[238][239][240].…”

“…Initially, the time resolution of these studies was limited to the ms-ns range [139][140][141][142], except for one groundbreaking case [143].Theoretical and experimental critical issues had to be considered to extend the feasibility of time-resolved XAS characterization to the sub-ns time domain.…”

Proposal to DOE Basic Energy Sciences: Ultrafast X-ray science facility at the Advanced Light Source

“…X-rays are ideal probes of atomic structure because they interact with core electronic levels that are closely bound to the atomic nucleus. A growing number of research groups around the world are applying ultrafast x-ray techniques to investigate structural dynamics in a variety of condensed matter systems [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22], however, future progress in this field is substantially limited at present due to the lack of suitable short-pulse x-ray sources.…”

Pump and probe X-ray absorption fine structure using high-brilliance photon sources

“…Most of the previous optical pumping experiments have been aimed at the photodissociation of ligands in haemeproteins; structural studies on CO-binding in myoglobin have been reported (Chance et al, 1983;Powers et al, 1987;Mills et al, 1984;Bianconi et al, 1994). Here we discuss the application of pump and probe XAFS to solid-state physics as a promising means of snapshot measurement of local lattice distortion, relaxation and, in some cases, bond alternation as a result of optical excitation of valence electrons.…”