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Molecular Beam Studies of Primary Photochemical Processes 初级光化学过程的分子束研究
Laser Chemistry Pub Date : 1982-12-01 DOI: 10.1155/LC.2.219
Yuan‐Pern Lee
{"title":"Molecular Beam Studies of Primary Photochemical Processes","authors":"Yuan‐Pern Lee","doi":"10.1155/LC.2.219","DOIUrl":"https://doi.org/10.1155/LC.2.219","url":null,"abstract":"Application of the method of molecular beam photofragmentation translational spectroscopy \u0000to the investigation of primary photochemical processes of polyatomic \u0000molecules is described.","PeriodicalId":296295,"journal":{"name":"Laser Chemistry","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1982-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125460754","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 1
Thermal Lensing Spectroscopy With Picosecond Pulse Trains and a New Dual Beam Configuration 皮秒脉冲序列和新的双光束结构的热透镜光谱
Laser Chemistry Pub Date : 1982-10-01 DOI: 10.1155/LC.1.9
J. Perry, E. Ryabov, A. Zewail
{"title":"Thermal Lensing Spectroscopy With Picosecond Pulse Trains and a New Dual Beam Configuration","authors":"J. Perry, E. Ryabov, A. Zewail","doi":"10.1155/LC.1.9","DOIUrl":"https://doi.org/10.1155/LC.1.9","url":null,"abstract":"In this communication, we wish to report on the use of synchronously mode-locked picosecond lasers in a pump-probe configuration for TL spectroscopy. The peak power for these picosecond lasers is very high and, of course, the fundamental of the dye laser (red beam) can be efficiently (~10%) doubled in frequency (U.V. beam) by second harmonic generation in nonlinear crystals. We use this generated U.V. beam as a probe to monitor the very weak absorption of the red beam. An arrangement [4] of the beams involving different waist positions for the pump and probe is used. This arrangement results in an enhancement of sensitivity (at least a factor of three to seven). Also, a different dependence of the signal on the cell position compared to the single beam method is obtained. Finally, we have obtained the Δν = 5 CH-stretching overtone absorption spectrum of liquid toluene with this method (see Figure 1). Suggestions are made regarding new applications of this picosecond pulse thermal lensing technique.","PeriodicalId":296295,"journal":{"name":"Laser Chemistry","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1982-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128413445","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 9
UV MULTIPHOTON INDUCED CHEMISTRY OF NITROBENZENE IN SOLUTION 紫外多光子诱导硝基苯溶液的化学性质
Laser Chemistry Pub Date : 1900-01-01 DOI: 10.1155/1990/42676
J. BelBruno, G. Siuzdak, S. North
{"title":"UV MULTIPHOTON INDUCED CHEMISTRY OF NITROBENZENE IN SOLUTION","authors":"J. BelBruno, G. Siuzdak, S. North","doi":"10.1155/1990/42676","DOIUrl":"https://doi.org/10.1155/1990/42676","url":null,"abstract":"The technique of Multiphoton Induced Chemistry (MPIC) has been employed to initiate ion-molecule \u0000chemistry of organic molecules in solution. We report one of the first examples of the use of liquid phase \u0000multiphoton ionization (MPI) to prepare organic cations, which then react with the solvent in ionmolecule \u0000processes. The products obtained in this chemical sequence are significantly different from those \u0000observed in conventional or multiphoton-induced neutral chemistry in the same solvent. The particular \u0000example explored in this work is the reactivity of the nitrobenzene cation in methanol solvent. Products of \u0000the ion-molecule chemistry, detected by gas chromatography/mass spectrometry, are phenol and benzyl \u0000alcohol. These products depend upon the square of the laser intensity. It is shown by ionization current \u0000measurements in a conductance cell, that ionic species are produced as precursors to the observed \u0000products. The implications of this application of MPI are briefly discussed. A preliminary report on the \u0000unimolecular chemistry of the highly excited neutral molecule is also included. The product of this channel \u0000is nitrosobenzene. It is shown, in this case, that the reactive state is most likely a highly vibrationally \u0000excited ground state molecule, not the lowest triplet level invoked in conventional photochemistry.","PeriodicalId":296295,"journal":{"name":"Laser Chemistry","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115320305","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 2
A Theoretical Study of theDynamics of Vibrational WavePackets in the 1g State Of Xe2 Xe2 1g态振动波包动力学的理论研究
Laser Chemistry Pub Date : 1900-01-01 DOI: 10.1155/1999/49417
J. Castillo, K. L. Reid
{"title":"A Theoretical Study of theDynamics of Vibrational WavePackets in the 1g State Of Xe2","authors":"J. Castillo, K. L. Reid","doi":"10.1155/1999/49417","DOIUrl":"https://doi.org/10.1155/1999/49417","url":null,"abstract":"We present a theoretical description of the dynamics of vibrational wave packets in the 1g state of Xe2. As an illustration, a simulation of a picosecond pump excitation-probe ionization laser experiment is carried out. The initial wavepacket is calculated using an explicit modelling of the short-pulse excitation process and propagated for up to 160 picoseconds. Evidence of fractional and full revivals of the wavepacket has been found and analyzed. The time delayed ionization signal is simulated using first order perturbation theory and shows clear oscillations corresponding to the temporal development of the wavepacket.","PeriodicalId":296295,"journal":{"name":"Laser Chemistry","volume":"51 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115763170","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 2
(2+2) Resonance enhanced multiphoton ionization spectra of jet-cooled ortho-, meta- and para-xylene (2+2)共振增强射流冷却邻二甲苯、间二甲苯和对二甲苯的多光子电离谱
Laser Chemistry Pub Date : 1900-01-01 DOI: 10.1155/LC.9.241
T. Blease, R. Donovan, P. Langridge-Smith, T. Ridley
{"title":"(2+2) Resonance enhanced multiphoton ionization spectra of jet-cooled ortho-, meta- and para-xylene","authors":"T. Blease, R. Donovan, P. Langridge-Smith, T. Ridley","doi":"10.1155/LC.9.241","DOIUrl":"https://doi.org/10.1155/LC.9.241","url":null,"abstract":"Two-photon spectra of the S1(Ã)–S0(X˜) transition of jet-cooled ortho-, meta- and para-xylene have been recorded in the region 43,000–37,000 cm−1 using resonance enhanced multiphoton ionization excitation. A full vibronic analysis for all three isomers has been carried out enabling the identification of several excited state vibrational frequencies for the first time. In particular, for ortho and para substitutions, a new, strong two-photon vibronic coupling mode ν19b has been identified, and the significance of this result is discussed. Some anomalies in the assignment of previously published spectra of the xylenes, and related disubstituted benzenes, have been observed and reassignments are suggested. In addition we show that the comparison of one and two-photon spectra provides a method for determining the mechanism by which totally symmetric fundamentals gain their intensity in one-photon spectra, namely either from Herzberg–Teller intensity stealing or due to favourable Franck–Condon overlap.","PeriodicalId":296295,"journal":{"name":"Laser Chemistry","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117158990","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 19
IR-Luminescence of CF2Cl2 Molecules in Multiple-Photon Excitation With Co2-Laser Radiation co2激光多光子激发下CF2Cl2分子的红外发光研究
Laser Chemistry Pub Date : 1900-01-01 DOI: 10.1155/LC.8.123
A. V. Dem’yanenko, G. A. Polyakov, A. Puretzky
{"title":"IR-Luminescence of CF2Cl2 Molecules in Multiple-Photon Excitation With Co2-Laser Radiation","authors":"A. V. Dem’yanenko, G. A. Polyakov, A. Puretzky","doi":"10.1155/LC.8.123","DOIUrl":"https://doi.org/10.1155/LC.8.123","url":null,"abstract":"We studied the IR luminescence spectra of vibrationally excited CF2Cl2 molecules \u0000resulting from excitation of the ν1 (1098 cm−1) and \u0000ν8 (922 cm−1) modes with a pulsed CO2 laser. \u0000The nonequilibrium spectra obtained under pumping conditions where their equilibrium counterparts \u0000coincide (the number of the photons absorbed per molecule being the same) were found to differ considerably. \u0000We suppose that this difference is due to different types of vibrational distribution formed as a result of the IR laser pumping. \u0000When pumping the ν1 mode, excitation of the R-branch occurs, resulting in the \u0000molecules “sticking” on the lower vibrational levels, whereas in the case of the ν8 mode, \u0000it is the P-branch that gets excited so that the molecules become easy to raise to high-lying vibrational levels.","PeriodicalId":296295,"journal":{"name":"Laser Chemistry","volume":"72 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117231513","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 2
Molecular Weight Distribution Generated on Initiation of Free RadicalPolymerization by Sequence of Laser Pulses 激光脉冲序列引发自由基聚合产生的分子量分布
Laser Chemistry Pub Date : 1900-01-01 DOI: 10.1155/1995/48258
A. Evseev, A. N. Nikitin
{"title":"Molecular Weight Distribution Generated on Initiation of Free RadicalPolymerization by Sequence of Laser Pulses","authors":"A. Evseev, A. N. Nikitin","doi":"10.1155/1995/48258","DOIUrl":"https://doi.org/10.1155/1995/48258","url":null,"abstract":"An investigation of molecular weight distributions (MWDs) resulting from initiation of free radical polymerization by an arbitrary sequence of short laser pulses has been undertaken. The analytical expressions have been derived to calculate MWDs for a polymerization scheme that contains reactions of chain initiation, propagation and termination by recombination or disproportionation. The MWDs produced by pulse-periodic irradiation have been calculated for a wide range of initiating pulses repetition rates (f = 0.05–100 Hz). The MWD dynamics in the act of polymerization and the influence of the duration of polymerization pseudostationary regime establishment upon the MWD have also been studied. The suitability of the derived expressions for describing the MWD generated by CW radiation before and after the establishment of polymerization quasi-stationary regime has been considered.","PeriodicalId":296295,"journal":{"name":"Laser Chemistry","volume":"14 3","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120860711","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 8
Multiple Photon High VibrationalCH Overtone Resonant andOne-Photon Dissociation ofToluene Radical Cation 多光子高振动ch泛音共振与甲苯自由基阳离子的单光子解离
Laser Chemistry Pub Date : 1900-01-01 DOI: 10.1155/LC.5.275
A. P. Simonov, G. Abakumov, V. T. Yaroslavtzev, V. A. Lunchev, E. A. Fedorov
{"title":"Multiple Photon High VibrationalCH Overtone Resonant andOne-Photon Dissociation ofToluene Radical Cation","authors":"A. P. Simonov, G. Abakumov, V. T. Yaroslavtzev, V. A. Lunchev, E. A. Fedorov","doi":"10.1155/LC.5.275","DOIUrl":"https://doi.org/10.1155/LC.5.275","url":null,"abstract":"Photodissociation of molecular radical cations of toluenes C7 H 8 +· (I), C6H5 CD 3 +· (II), \u0000C7 D 8 +· (III), cycloheptatriene C7 H 8 +· (IV), and benzene has been studied by the method \u0000of two-pulse two-colour laser photolysis of molecules in a mass spectrometer using \u0000wavelengths 1064, 532, and 355 nm. The I ions formed due to sequential two-photon \u0000ionization of toluene molecules by the 266 nm radiation isomerize supposingly into \u00005-methylene-cyclohexadiene (VI). Two- and three-photon stepwise dissociation of the I \u0000and II isomers (VI and VI-d3, respectively) induced by the 1064 nm radiation has a \u0000resonance at the third overtone level of CH aliphatic bond stretching vibrations. Internal \u0000energy randomization in the two-photon dissociation is much less for VI-d3 as compared \u0000to VI. The mechanisms of isoenergetic dissociation (two- and one-photon processes \u0000induced by the 1064 and 532 nm radiations, respectively) are different: the one-photon \u0000decay via an electronically excited state proceeds considerably faster than the two-photon \u0000decomposition does in the ground state. The photodissociation cross sections \u0000have been determined. It has been shown that the intensity of CH stretching vibration \u0000overtones can be essentially higher for radical cations than for the neutral molecules.","PeriodicalId":296295,"journal":{"name":"Laser Chemistry","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127231499","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 1
Kinetics of Laser Induced Plasma on an Aqueous Surface 激光诱导等离子体在水表面的动力学
Laser Chemistry Pub Date : 1900-01-01 DOI: 10.1080/02786270215154
J. Ahmed, Z. B. Lakhdar, G. Taieb
{"title":"Kinetics of Laser Induced Plasma on an Aqueous Surface","authors":"J. Ahmed, Z. B. Lakhdar, G. Taieb","doi":"10.1080/02786270215154","DOIUrl":"https://doi.org/10.1080/02786270215154","url":null,"abstract":"Emission spectra of MgI and MgII from a plasma induced by the interaction of a laser pulse with the surface of aqueous solutions of MgCl 2 , were recorded by a time resolved spectroscopy method to obtain information on the processes involved in the formation and the evolution of the two different species. A kinetic model based on ion-electron recombination produced during the relaxation of the plasma is constructed with the aim to explain the origin and the temporal shift of observed Mg + and Mg emissions. Comparison with the experimental results is presented and discussed.","PeriodicalId":296295,"journal":{"name":"Laser Chemistry","volume":"83 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127469258","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 12
Laser Ablation Studies of Deposited Silver Colloids Active in SERS 激光烧蚀在SERS中活性沉积银胶体的研究
Laser Chemistry Pub Date : 1900-01-01 DOI: 10.1080/02786270212132
R. Porte, D. S. Moreno, M. Striano, M. Munñoz, J. García-Ramos, S. S. Cortés, E. Koudoumas
{"title":"Laser Ablation Studies of Deposited Silver Colloids Active in SERS","authors":"R. Porte, D. S. Moreno, M. Striano, M. Munñoz, J. García-Ramos, S. S. Cortés, E. Koudoumas","doi":"10.1080/02786270212132","DOIUrl":"https://doi.org/10.1080/02786270212132","url":null,"abstract":"Laser ablation of deposited silver colloids, active in SERS, is carried out at three different laser wavelengths (KrF, XeCl and Nd:YAG at λ = 248, 308 and 532 nm respectively). Emission form excited neutral Ag and Na atoms, present in the ablation plume, is detected with spectral and temporal resolution. The expansion velocity of Ag in the plume is estimated in ~1×104m s−1. Low-fluence laser ablation of the colloids yields ionized species that are analyzed by time-of-flight mass spectroscopy. Na","PeriodicalId":296295,"journal":{"name":"Laser Chemistry","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124862559","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 4
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