Next Article in Journal
Next Article in Special Issue
Previous Article in Journal
Molecules 2014, 19(2), 2410-2433; doi:10.3390/molecules19022410
Review

Ultrafast Internal Conversion of Aromatic Molecules Studied by Photoelectron Spectroscopy using Sub-20 fs Laser Pulses

1,2,3
Received: 5 December 2013; in revised form: 8 February 2014 / Accepted: 12 February 2014 / Published: 21 February 2014
(This article belongs to the Special Issue Photoelectron Spectroscopy)
View Full-Text   |   Download PDF [2665 KB, uploaded 18 June 2014]
Abstract: This article describes our recent experimental studies on internal conversion via a conical intersection using photoelectron spectroscopy. Ultrafast S2(ππ*)–S1(*) internal conversion in pyrazine is observed in real time using sub-20 fs deep ultraviolet pulses (264 and 198 nm). While the photoelectron kinetic energy distribution does not exhibit a clear signature of internal conversion, the photoelectron angular anisotropy unambiguously reveals the sudden change of electron configuration upon internal conversion. An explanation is presented as to why these two observables have different sensitivities to internal conversion. The 198 nm probe photon energy is insufficient for covering the entire Franck-Condon envelopes upon photoionization from S2/S1 to D1/D0. A vacuum ultraviolet free electron laser (SCSS) producing 161 nm radiation is employed to solve this problem, while its pulse-to-pulse timing jitter limits the time resolution to about 1 ps. The S2S1 internal conversion is revisited using the sub-20 fs 159 nm pulse created by filamentation four-wave mixing. Conical intersections between D1(π−1) and D0(n−1) and also between the Rydberg state with a D1 ion core and that with a D0 ion core of pyrazine are studied by He(I) photoelectron spectroscopy, pulsed field ionization photoelectron spectroscopy and one-color resonance-enhanced multiphoton ionization spectroscopy. Finally, ultrafast S2(ππ*)–S1(ππ*) internal conversion in benzene and toluene are compared with pyrazine.
Keywords: photoelectron spectroscopy; femtosecond; laser; filamentation; ultraviolet; imaging; pyrazine; benzene; toluene; internal conversion; ionization photoelectron spectroscopy; femtosecond; laser; filamentation; ultraviolet; imaging; pyrazine; benzene; toluene; internal conversion; ionization
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Export to BibTeX |
EndNote


MDPI and ACS Style

Suzuki, T. Ultrafast Internal Conversion of Aromatic Molecules Studied by Photoelectron Spectroscopy using Sub-20 fs Laser Pulses. Molecules 2014, 19, 2410-2433.

AMA Style

Suzuki T. Ultrafast Internal Conversion of Aromatic Molecules Studied by Photoelectron Spectroscopy using Sub-20 fs Laser Pulses. Molecules. 2014; 19(2):2410-2433.

Chicago/Turabian Style

Suzuki, Toshinori. 2014. "Ultrafast Internal Conversion of Aromatic Molecules Studied by Photoelectron Spectroscopy using Sub-20 fs Laser Pulses." Molecules 19, no. 2: 2410-2433.



Molecules EISSN 1420-3049 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert