The stroboscopic gas electron diffraction method for investigation of time-resolved structural kinetics in photoexcitation processes

Abstract The emergence of a novel tool of structural chemistry is reviewed; pulsed-electron beam (stroboscopic) gas electron diffraction (GED) synchronous with photoexcitation. About 10 years ago, the first stroboscopic electron diffraction experiments of irradiated gaseous species were performed at Moscow State University, yielding qualitative evidence that intensity changes upon irradiation can be detected in this way. More recently, development of prototype on-line GED data recording techniques at the University of Arkansas allowed for the first successful observations, with quantitatively model-fitted GED signals, of photochemical reactions, i.e. the 193 nm photodissociations of carbon disulfide and of chlorine-substituted ethenes. In addition to summarizing some of the current structural work, the paper describes the characteristic aspects of pulsed-beam GED, the requisite on-line data recording, and non-conventional data analysis techniques capable of interpreting GED signals from non-equilibrium ensembles in arbitrary vibrational states.

[1]  S. Brueck,et al.  ν3 mode absorption behavior of CO2 laser excited SF6 , 1979 .

[2]  M. Kawasaki,et al.  Energy distribution of the fragments produced by photodissociation of CS2 at 193 nm , 1980 .

[3]  I. Hargittai,et al.  Electron diffraction study of the molecular structure of germanium dibromide , 1982 .

[4]  L. Bartell,et al.  Electron diffraction studies of hot molecules. I. Observed and calculated thermal expansions of SF6, CF4, and SiF4 , 1982 .

[5]  W. Vance,et al.  Electron diffraction studies of hot molecules. III. Stretching and bending anharmonicity in CF3Cl , 1984 .

[6]  Flash EXAFS for structural analysis of transient species: rapidly melting aluminum , 1983 .

[7]  R. Ryhage,et al.  An Electron Diffraction Investigation of the Free Radical Triphenylmethyl in the Gas Phase. , 1965 .

[8]  David L. Monts,et al.  Gas Electron Diffraction Study of the 193-nm Laser-Induced Interconversion between Cis- and Trans-1,2-Dichloroethylene , 1987 .

[9]  L. Schäfer.  Erratum: ''Electron Diffraction as a Tool of Structural Chemistry'' , 1976 .

[10]  Hani E. Elsayed-Ali,et al.  Ultrahigh vacuum picosecond laser‐driven electron diffraction system , 1990 .

[11]  L. Schäfer,et al.  Real-Time Electron Diffraction. Part III: Image Transfer via Fiber Optics , 1989 .

[12]  A. Compaan,et al.  Raman Measurement of Lattice Temperature during Pulsed Laser Heating of Silicon , 1980 .

[13]  G. Mourou,et al.  Picosecond reflection high‐energy electron diffraction , 1988 .

[14]  Lothar Schäfer,et al.  Instrumentation for time-resolved electron diffraction , 1990 .

[15]  C. Djerassi,et al.  An Electron Diffraction Investigation of the Molecular Structure of Di-t-butylnitroxide Free Radical in the Vapour Phase. , 1966 .

[16]  G. J. Galvin,et al.  Measurement of the Velocity of the Crystal-Liquid Interface in Pulsed Laser Annealing of Si , 1982 .

[17]  E. Rothe,et al.  Two-step photoionization of Na2: dependence on alignment , 1981 .

[18]  L. Bartell,et al.  Electron diffraction studies of laser‐pumped molecules. I. Characterization of system and analysis of data , 1981 .

[19]  Meier,et al.  Elastic electron scattering from CH3I molecules oriented in the gas phase. , 1992, Physical review letters.

[20]  V. P. Spiridonov,et al.  A stroboscopical gas-electron diffraction method for the investigation of short-lived molecular species , 1983 .

[21]  R. Bernstein,et al.  Focusing and Orientation of Symmetric‐Top Molecules with the Electric Six‐Pole Field , 1965 .

[22]  P. Schulze,et al.  On an electron diffraction study of the structure of the dibromomethylene radical , 1974 .

[23]  D. A. Kohl,et al.  Electron diffraction study of the thermal decomposition of BrCCl3 , 1973 .

[24]  W. Fuß.  The v2 + v6 absorption and emission of multiphoton-excited SF6 , 1980 .

[25]  L. Bartell,et al.  Rapid Procedure for Rigorous Analysis of Electron Diffraction Data , 1959 .

[26]  M. Harith,et al.  Pulsed laser annealing of GaAs and Si: Combined reflectivity and time‐of‐flight measurements , 1983 .

[27]  Linus Pauling,et al.  The Radial Distribution Method of Interpretation of Electron Diffraction Photographs of Gas Molecules , 1935 .

[28]  W. Leung,et al.  A 193 nm laser photofragmentation time‐of‐flight mass spectrometric study of CS2 and CS2 clusters , 1988 .

[29]  R. Zare,et al.  Effect of reagent orientation and rotation upon product state distribution in the reaction Sr+HF (v=1,J) →SrF(v′, J′) +H , 1978 .

[30]  V. Letokhov,et al.  Multiple-Photon Infrared Laser Photophysics and Photochemistry. II , 1983 .

[31]  C. Rettner,et al.  Effect of atomic reagent approach geometry on reactivity: Reactions of aligned Ca(1P1) with HCl, Cl2, and CCl4 , 1982 .

[32]  C. Manus,et al.  A new effect in multiphoton photoeffect of a gold surface induced by picosecond laser pulses , 1978 .

[33]  W. Faust,et al.  Improvements in real‐time data acquisition for gas electron diffraction , 1986 .

[34]  Richart E. Slusher,et al.  Time‐resolved reflectivity of ion‐implanted silicon during laser annealing , 1978 .

[35]  G. Mourou,et al.  Time-Resolved Laser-Induced Phase Transformation in Aluminum , 1984, Topical Meeting on Ultrafast Phenomena.

[36]  Ahmed H. Zewail,et al.  Ultrafast diffraction and molecular structure , 1992 .

[37]  L. Bartell,et al.  Calculation of radial distribution functions for molecules in excited vibrational states , 1979 .

[38]  G. Porter.  The absorption spectroscopy of substances of short life , 1950 .

[39]  Nicolaas Bloembergen,et al.  Picosecond time‐resolved plasma and temperature‐induced changes of reflectivity and transmission in silicon , 1982 .

[40]  E. Mazur,et al.  Collisionless vibrational energy redistribution between infrared and Raman active modes in SF6 , 1984 .

[41]  V. P. Spiridonov,et al.  The cumulant method in diffraction analysis of polyatomic molecules , 1988 .

[42]  Seung E. Choi,et al.  Theory of oriented symmetric‐top molecule beams: Precession, degree of orientation, and photofragmentation of rotationally state‐selected molecules , 1986 .

[43]  G. Porter,et al.  Photolysis of Chlorine Dioxide and Absolute Rates of Chlorine Monoxide Reactions , 1954, Nature.

[44]  P. A. Schulz,et al.  Simple bond rupture reactions in multiphoton dissociation of molecules , 1979 .

[45]  I. Hargittai,et al.  Combined electron diffraction/mass-spectrometric investigation of the molecular structure of germanium dichloride , 1979 .

[46]  B. Krohn,et al.  Force-field model for the stretching anharmonicities of sulfur hexafluoride , 1984 .

[47]  J. Fujimoto,et al.  Picosecond laser interaction with metallic zirconium , 1982 .

[48]  D. M. Mills,et al.  Synchrotron x-ray diffraction study of silicon during pulsed laser annealing , 1982 .

[49]  N. Bloembergen,et al.  Thermally assisted multiphoton photoelectric emission from tungsten , 1980 .

[50]  L. Bartell,et al.  Electron diffraction studies of hot molecules. II. ‘‘Anharmonic shrinkage effects’’ in SF6, CF4, and SiF4 , 1982 .

[51]  M. Kimura,et al.  A Reinvestigation of Small-angle Electron Scattering by CS2 and CCl4 Molecules , 1982 .

[52]  R. G. Rehm,et al.  Vibrational Relaxation of Anharmonic Oscillators with Exchange‐Dominated Collisions , 1968 .

[53]  R. Yen,et al.  Time-Resolved Reflectivity Measurements of Femtosecond-Optical-Pulse-Induced Phase Transitions in Silicon , 1983 .

[54]  G. Mourou,et al.  A picosecond jitter streak camera , 1980 .

[55]  L. Bartell,et al.  Electron diffraction studies of laser‐pumped molecules. II. Collisionally assisted absorption by SF6 , 1981 .

[56]  W. Jackson,et al.  Coaxial measurement of the translational energy distribution of CS produced in the laser photolysis of CS2 at 193 nm , 1985 .

[57]  David L. Monts,et al.  Molecular electron diffraction from a space‐charge limited beam , 1988 .

[58]  W. Faust,et al.  On‐line gas electron diffraction identification of gas chromatography effluents (GC‐GED) , 1988 .

[59]  H. Yoshizawa,et al.  Neutron Diffraction Experiment on a Randomly Mixed Antiferromagnet with Competing Spin Anisotropies , 1980 .

[60]  R. Martin,et al.  Orientation dependence in the reaction of Xe* with photodissociation polarized IBr , 1983 .

[61]  I. Smith.  Exposing molecular motions , 1990, Nature.

[62]  M. Quack,et al.  Absolute rate parameters for infrared photochemistry: CF3I→CF3+I , 1982 .

[63]  J. Stanton,et al.  Electron diffraction studies of hot molecules. IV. Asymmetries of nonbonded distribution functions of SF6, SiF4, and CF4 , 1984 .

[64]  Lothar Schäfer,et al.  Real‐time data acquisition for gas electron diffraction , 1984 .

[65]  V. P. Spiridonov,et al.  A new intensity equation for electron diffraction analysis: A barrier to pseudorotation in PF5 from diffraction data , 1981 .

[66]  L. Bartell,et al.  Electron diffraction studies of laser‐pumped molecules. IV. SF6, experiment and theory , 1984 .

[67]  Lothar Schäfer,et al.  Instrumentation for gas electron diffraction employing a pulsed electron beam synchronous with photoexcitation , 1992 .

[68]  R. Becker,et al.  Low-Energy Electron Diffraction during Pulsed Laser Annealing: A Time- Resolved Surface Structural Study , 1984 .