The intermolecular vibrations of Ar–styrene and Ar–4-fluorostyrene complexes

Abstract

One-color (1-1-1) resonance enhanced multiphoton ionization (R EM PI) spectra are reported for styrene-Ar" clusters with n = 2, 3, and for 4-fluorostyrene-Ar" clusters with n -2-5. These spectra are compared with previously recorded spectra of the mono-Ar complexes and discussed in relation to the structures of the clusters. For the mono-Ar complexes we have performed practically exact quantum calculations of the van der Waals vibrational frequencies and prop erties, starting from two different empirical atom-atom potentials. The intermolecular potentials are strongly anharmonic and, due to the low symmetry of these dimers, we find considerable mode mixing. As a consequence of the kinematic coupling between the Ar motion and the internal rotation, the bending frequencies depend considerably on the different rotational con stants of the molecules. The order of the fundamental frequencies is the same for both dimers. For Ar-4-fluorostyrene the calculated vibrational frequencies agree well with the observed spectrum; the van der Waals side bands can thus be assigned in detail. For Ar-styrene the observed frequencies are less well reproduced, so we must conclude that the atom-atom poten tial used is substantially better for Ar-fluorostyrene than for Ar-styrene.

Conformational Landscape of Supersonically Expanded 1‐(Fluorophenyl)ethanols and Their Monohydrated Clusters

“…The experimental setup to produce the molecular clusters and to perform mass-resolved R2PI has been described elsewhere. [42] Briefly, a pulsed supersonic beam was obtained by adiabatic expansion of a carrier gas (Ar; stagnation pressure from 2 to 4 bar) seeded with the chromophore (and water) through a pulsed nozzle (internal diameter: 800 mm; aperture time: 200 ms; repetition rate: 10 Hz) heated at T = 80 8C. Their concentration is maintained low enough to minimize the production of heavier clusters.…”

Free jet rotational spectrum of the most stable conformer of 1-(2-fluorophenyl)-1-ethanol

“…Important results have been obtained by resonanttwo-photon-ionization (R2PI) excitation spectra of the S 1 S 0 transition of mass resolved hydrogen bonded molecular complexes [1][2][3][4][5][6]. To observe the electronic transitions of chiral systems -typically their fluorescence spectrum -this technique requires a chromophoric group.…”

Photochemical R2PI study of chirality and intermolecular forces in supersonic beam

“…Procedure. The experimental setup, which combines a supersonic molecular beam, two Nd-YAG pumped dye lasers and a time of flight (TOF) mass spectrometer, has been already described [6]. Molecules and clusters in the beam are resonantly ionized by two photons coming from tunable dye lasers pumped by the same Nd-YAG laser.…”