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Bellm SM, Davies JA, Whiteside PT, Guo J, Powis I, Reid KL. An unusual π* shape resonance in the near-threshold photoionization of S1 para-difluorobenzene. J Chem Phys 2005; 122:224306. [PMID: 15974667 DOI: 10.1063/1.1927523] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Previously reported dramatic changes in photoelectron angular distributions (PADs) as a function of photoelectron kinetic energy following the ionization of S1 p-difluorobenzene are shown to be explained by a shape resonance in the b(2g) symmetry continuum. The characteristics of this resonance are clearly demonstrated by a theoretical multiple-scattering treatment of the photoionization dynamics. New experimental data are presented which demonstrate an apparent insensitivity of the PADs to both vibrational motion and prepared molecular alignment, however, the calculations suggest that strong alignment effects may nevertheless be recognized in the detail of the comparison with experimental data. The apparent, but unexpected, indifference to vibrational excitation is rationalized by considering the nature of the resonance. The correlation of this shape resonance in the continuum with a virtual pi* antibonding orbital is considered. Because this orbital is characteristic of the benzene ring, the existence of similar resonances in related substituted benzenes is discussed.
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Affiliation(s)
- Susan M Bellm
- School of Chemistry, University of Nottingham, Nottingham NG7 2RD, United Kingdom
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Bellm SM, Reid KL. Reevaluation of the use of photoelectron angular distributions as a probe of dynamical processes: strong dependence of such distributions from s1 paradifluorobenzene on photoelectron kinetic energy. PHYSICAL REVIEW LETTERS 2003; 91:263002. [PMID: 14754048 DOI: 10.1103/physrevlett.91.263002] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2003] [Indexed: 05/24/2023]
Abstract
Photoelectron angular distributions (PADs) have been measured following the excitation of the S1 origin band in paradifluorobenzene using a range of ionizing wavelengths and for resolved ion vibrational states. The PADs show a dramatic sensitivity to the photoelectron kinetic energy over an energy range of at least 1 eV from threshold, and almost no sensitivity to any prepared intermediate state alignment. This has important consequences for those studies of intramolecular dynamics that use PADs. We suggest that the observed behavior is caused by a shape resonance in the continuum.
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Affiliation(s)
- Susan M Bellm
- School of Chemistry, University of Nottingham, Nottingham NG7 2RD, United Kingdom
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Abstract
Angle-resolved photoelectron spectroscopy has been performed for more than 70 years in various guises, but recently its potential to help solve in detail problems in the photoionization dynamics and intramolecular dynamics of gas-phase molecules has been recognized. One key development has been the design of experiments in appropriate geometries to extract information that pertains to the molecular frame, another has been the development of imaging spectrometers, and a third is the use of ultrafast lasers to cause photoionization. In this review, which is aimed at experimentalists, simple expressions for photoelectron angular distributions (PADs) in various experimental geometries are given and their applications explained.
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Affiliation(s)
- Katharine L Reid
- School of Chemistry, University of Nottingham, Nottingham NG7 2RD, United Kingdom.
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Affiliation(s)
- William A. Chupka
- Sterling Chemistry Laboratory, Yale University, New Haven, Connecticut 06520-8107
| | - Edward R. Grant
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907
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Parker DH, Eppink ATJB. Photoelectron and photofragment velocity map imaging of state-selected molecular oxygen dissociation/ionization dynamics. J Chem Phys 1997. [DOI: 10.1063/1.474624] [Citation(s) in RCA: 204] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Sha G, Proch D, Kompa KL. Photoelectron angular distribution and ion vibrational branching ratio: The (2+1)‐photon ionization of E 1Π‐state‐aligned CO molecules. J Chem Phys 1993. [DOI: 10.1063/1.465698] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Sha G, Proch D, Rose C, Kompa KL. Photoelectron angular distributions and vibrational branching ratios of CO (2+1)‐photon ionization via the B 1Σ+ state. J Chem Phys 1993. [DOI: 10.1063/1.466087] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Appling JR, Harbol MR, Edgington RA, Goren AC. Photoelectron spectroscopy of sulfur atoms produced via two‐photon dissociation of sulfur dioxide. J Chem Phys 1992. [DOI: 10.1063/1.463933] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Braunstein M, McKoy V, Dixit SN. Rotationally resolved photoionization of molecular oxygen. J Chem Phys 1992. [DOI: 10.1063/1.462671] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Ondrey GS, Rose C, Proch D, Kompa KL. Resonant multiphoton ionization dynamics of N2 via the a 1Πg(v=10–14) states: Preparation of state‐selected N+2 X 2Σ+g(v+=0–4) ions. J Chem Phys 1991. [DOI: 10.1063/1.461311] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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de Beer E, Born M, de Lange C, Westwood N. A rotationally resolved REMPI-PES study of the NH radical. Chem Phys Lett 1991. [DOI: 10.1016/0009-2614(91)80189-5] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Wu M, Taylor DP, Johnson PM. Resonance enhanced multiphoton ionization photoelectron spectra of CO2. II. Competition between photoionization and dissociation. J Chem Phys 1991. [DOI: 10.1063/1.461082] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Stephens JA, McKoy V. Orbital evolution and promotion effects in the photoionization dynamics of2Σ−Rydberg states of OH. J Chem Phys 1990. [DOI: 10.1063/1.459368] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Braunstein M, McKoy V, Dixit SN, Tonkyn RG, White MG. Shape resonance effects in the rotationally resolved photoelectron spectra of O2. J Chem Phys 1990. [DOI: 10.1063/1.459654] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Pratt ST, Dehmer JL, Dehmer PM. Two‐photon spectroscopy of Rydberg states of molecular oxygen. J Chem Phys 1990. [DOI: 10.1063/1.458841] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Stephens JA, Braunstein M, McKoy V. Multiplet‐specific shape resonance and autoionization effects in (2+1) resonance enhanced multiphoton ionization of O2 via the d 1Πg state. J Chem Phys 1990. [DOI: 10.1063/1.458511] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Tonkyn RG, Winniczek JW, White MG. Photoionization and photoelectron spectroscopy of O2 with coherent vacuum ultraviolet radiation. J Chem Phys 1989. [DOI: 10.1063/1.457381] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Koenders BG, Koeckhoven SM, Kuik GJ, Drabe KE, de Lange CA. Photoelectron spectroscopic studies of multiphoton processes in molecular chlorine involving the 2 1∏gRydberg state. J Chem Phys 1989. [DOI: 10.1063/1.457422] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Allendorf SW, Leahy DJ, Jacobs DC, Zare RN. High‐resolution angle‐ and energy‐resolved photoelectron spectroscopy of NO: Partial wave decomposition of the ionization continuum. J Chem Phys 1989. [DOI: 10.1063/1.457030] [Citation(s) in RCA: 110] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Stephens JA, McKoy V. Non-Franck-Condon effects induced by orbital evolution and Cooper minima in excited-state photoionization of OH. PHYSICAL REVIEW LETTERS 1989; 62:889-892. [PMID: 10040364 DOI: 10.1103/physrevlett.62.889] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Braunstein M, Stephens JA, McKoy V. Shape resonance and non‐Franck–Condon effects in (2+1) resonant enhanced multiphoton ionization of O2 via the C 3Πg state. J Chem Phys 1989. [DOI: 10.1063/1.456142] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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