Resonant two-photon ionization of van der Waals adducts of 4-fluorostyrene with monomethylamine and monoethylamine: intracluster chemical reactions (original) (raw)
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Journal of Chemical Sciences, 1993
Research on the formation and properties of clusters of aromatic molecules bonded to numerous solvents is rapidly expanding. Recently much attention has been paid to these adduct species with the objective of clarifying nucleation phenomena. Photophysical and photochemical studies of these clusters give information on solvent effects, intracluster reactions and charge-transfer processes. Model calculations of potential surfaces of vdW adducts have provided knowledge of the intracluster binding energy and vdW vibrational modes in a few systems. Here, data are reported on resonant two-photon ionization R2PI mass spectra and on spectroscopic shifts of styrenes clustered with various atoms and molecules.
Resonant two-photon ionization spectra of p-difluorobenzene mixed van der Waals complexes
Journal of Molecular Structure, 2009
Van der Waals heterodimers of p-difluorobenzene (DFB) with other molecules, prepared in a supersonic jet beam expansion, were studied by resonant two-photon ionization (R2PI) through their S 1 S 0 transition. The functional molecule in these systems is DFB. The partners-molecules are: p-difluorobenzene (homodimer), fluorobenzene, 1,3,5-trifluorobenzene, furan, N-methylpyrrole, ethanol and propargyl alcohol. In each case, the recorded spectra are relatively broad as the result of at least two structures present in the molecular beam. Using hexafluorobenzene or pyrrole as partners of DFB, the S 1 S 0 transition of the respective heterodimer was not detected. Intracluster ion-molecule reactions have been observed in the cases of p-difluorobenzene with ethanol and propargyl alcohol.
Electronic spectroscopy of fluorobenzene Van der Waals molecules by resonant two-photon ionization
Chemical Physics, 1983
Van der Waals (vdW) clusters of fluorohenzene (FB). synthesized in a seeded supersonic rare-_g;ls expxwion were studied bv laser-induced. resonant two-photon ionization (RZPI) combined with TOF-mass spectrometry. The m&c&z xere excited near the FB monomeis vibronic origin of the S,(zz*) + S, transition (X,, = _ 1644 .A). The heterogeneous clusters FB-.L\r_ (n-= 4) showed specific shifts of the O-O band relative to X,, induced by vdW interaction (FB-Ar:-23 cm-': FB- .-Xr,:-46 cm-': FB-Ar,: +4.6 cm-'). Additional satellite bands appeared due to intermolecular photofru_gmsntation. A second band found for FB-Ar at 20 cm-' was assigned to ;I vdW vibration (v,,, = 43 cm-'). Similar rsbults were obtained for FB-KS; (!I c 3). The spectra of the homogeneous clusters F& and FB, were more complex. The dimer spectrum hho\ved two broad spectral features. one blue-the other red-shifted relative to X,,. Each one is probably due to 3 different ijomsr. The blue-shifted contained progressions. which were tentatively assigned to a vdW vibration with 10 cm-' in the ground and 15 cm-' in the excited stale. The [timer spectrum showed a broad blue-shifted absorption maximum with prominent blrnds at-2.6.-20.-29 and-50 cm-'-From the obsewed spectra the feasibility of cluster-specific spscwoscopy is discuascd.
Resonant two-photon ionization combined with time-of-flight mass spectrometry was applied for the interrogation of the So --S I electronic-vibrational excitations of van der Waals complexes of fluorene (FL) with rare-gas atoms and N2 in supersonic jets. Energy-resolved and mass-resolved spectra of FL· Ne. FL· Ar. (n = 1-3), FL· Kr, FL· Xe, and FL· N, were recorded over the energy range 0-800 cm-I above the electronic origin of S I' The red microscopic spectral shifts of the electronic origins of FL . R (R = Ar, Kr, and Xe) complexes are dominated by dispersive interactions, being proportional to the polarizability of R. The vibrational level structure of FL . R. (R = Ar, Kr, and Xe) complexes exhibits intramolecular vibrational excitations of FL, as well as intermolecular vibrations, which involve the relative motion of FL and R in the complex. The spectra of FL· Ne and FL· N, reveal a rich vibrational structure in the vicinity of the electronic origin, indicating a substantial change of the nuclear configuration upon electronic excitation. Upper and lower bounds on the dissociation energies of FL· R (R = Ne, Kr, and Xe) and FL· Ar, were inferred from the vibrational level structure in the mass-resolved spectra, where the disappearance of the signal of the parent van der Waals ion and the appearance of the ion signal of the fragments mark the onset of the vibrational predissociation process.
Electronic spectroscopy of large van der waals molecules by resonant two-photon ionization
Chemical Physics Letters, 1982
Rcccwcd 16 November 1981, m final form 15 Dcccmbcr 1981 Tunable laser two-photon 1on1za11on oTkugc van dcr Wdsls molcculcs, combmcd wrth tune-of-fl@t mass spectroscopy. WE applied to the idcntfxatlon ol the clcctiomc orlgn and of some low wbnllonal cwtatlons of the Su -S, clcctromc transihon ol fluorcwhr,, fluorcnc AI, and lluorcnc Krr produrcd In supcrsomc c\p.mslons [Zl] 2 Berkowtch-Y&n, J Jortner, S. Leutwylerand U. Even, to be published 1221 J P. hlarer and D.W. Tumcr, faraday Discussion Chcm sot. 54 (1972) 149
Resonant two-photon ionization of fluorene rare-gas van der Waals complexes
The Journal of Chemical Physics, 1983
Resonant two-photon ionization combined with time-of-flight mass spectrometry was applied for the interrogation of the So --S I electronic-vibrational excitations of van der Waals complexes of fluorene (FL) with rare-gas atoms and N2 in supersonic jets. Energy-resolved and mass-resolved spectra of FL· Ne. FL· Ar. (n = 1-3), FL· Kr, FL· Xe, and FL· N, were recorded over the energy range 0-800 cm-I above the electronic origin of S I' The red microscopic spectral shifts of the electronic origins of FL . R (R = Ar, Kr, and Xe) complexes are dominated by dispersive interactions, being proportional to the polarizability of R. The vibrational level structure of FL . R. (R = Ar, Kr, and Xe) complexes exhibits intramolecular vibrational excitations of FL, as well as intermolecular vibrations, which involve the relative motion of FL and R in the complex. The spectra of FL· Ne and FL· N, reveal a rich vibrational structure in the vicinity of the electronic origin, indicating a substantial change of the nuclear configuration upon electronic excitation. Upper and lower bounds on the dissociation energies of FL· R (R = Ne, Kr, and Xe) and FL· Ar, were inferred from the vibrational level structure in the mass-resolved spectra, where the disappearance of the signal of the parent van der Waals ion and the appearance of the ion signal of the fragments mark the onset of the vibrational predissociation process.
Absolute two-photon ionization yields for selected organic molecules at 248 nm
Journal of The Optical Society of America B-optical Physics, 1985
Absolute two-photon ionization yields for benzene, fluorobenzene, diethylaniline, and trimethylamine have been measured at 248 nm as a function of KrF laser fluence for two pulse lengths of approximately 8 and 20 nsec. We have also investigated NO ionization yields at 226 and 193 nm. The ionization is a resonant process that can be modeled as a four-level system. From the data, we derive ground-state absorption cross sections, intermediatestate ionization cross sections, and effective intermediate-state lifetimes. In some cases, a small contribution to the ionization yield from a direct nonresonant two-photon process can be inferred from the model. 0740-3224/85/060877-09$02.00
R2PI detection and spectroscopy of van der Waals complexes of 4-fluorostyrene with rare gases
Chemical Physics Letters, 1995
One-color resonance-enhanced two-photon ionization spectra of jet-cooled 4-fluorostyrene van der Waals complexes with Ne, Ar, Kr, Xe are reported. The measured spectra display discrete structure and allow the identification of electronic spectral shifts as well as stretching and bending frequencies of the various complexes. These spectra are interpreted with the help of simple model calculations. 0009-2614/95/$09.50 6 1995 Elsevier Science B.V. All rights reserved SSDI 0009-2614(95)00264-2
The Journal of Physical Chemistry, 1983
The photodissociation of vibrationally excited CFJ+ and CF3Br+ by a single infrared photon has been studied in a high-energy ion beam. This process is equivalent to the final step of multiphoton photodissociation. The photofragment dynamics have been investigated. The angular distribution of the photofragments was found to be isotropic. Kinetic energy release distributions of the products have been measured and are in good agreement with the predictions of statistical phase theory. Data on the single-photon photodissociation spectrum measured as a function of ion source temperature are presented and compared with the room temperature multiphoton photodissociation spectrum. In addition, the rate of collisional quenching by Xe of the single-photon photodissociation has been investigated.