Resonance enhanced multiphoton ionisation spectroscopy of dimethyl sulfide

Abstract

We report the first multiphoton study of the electronic spectrum of the dimethyl sulfide molecule. The interpretation we present is based on analysis of the two-and three-photon resonance enhanced multiphoton ionisation (REMPI) spectra and measurements of the kinetic energies of the photoelectrons resulting from the REMPI process. Members of four (possibly five) Rydberg series are identified and a refined value of the first ionisation limit of dimethyl sulfide is obtained: E i = 8.710 & 0.005 eV (70250 & 40 cm-'). As in our previous study of the related divalent sulfide methanethiol, we detect the presence of slower electrons in the photoelectron spectra which can be interpreted in terms of near resonant inter-Rydberg state vibronic mixing.

Laser photoelectron spectroscopy: spectroscopy and dynamics of excited states in small and medium‐sized molecules

“…We shall focus on the energy range from -50,000-69,000cm-1. The lowest ionic limit was obtained in our REMPI-PES work at 70,250 f 40cm-I [46]. This value agrees very well with previous ones obtained by extrapolation of Rydberg series observed in one-photon absorption spectroscopy , and by conventional PES [33].…”

“…Simihr to the situation with conventional PES where molecular orbitals became experimentally accessible in a direct way 127-341, laser PES has now developed to the point where orbital interactions between orbitals with different cores can be made experimentally "visible" for the first time. Many examples exist to date in systems as diverse as N [35] and S atoms [36,37], the NH radical [38,39], the SH radical [40,41], N20 [42], NH3 [43,441, methanethiol [45], and dimethyl sulfide [46]. The role of orbital interactions in laser PES will prove to be one of the key elements of the research described in this contribution.…”

Vibronic coupling in excited states of acetone

“…As amply demonstrated in previous studies, [32][33][34][35][36] this approach has unique advantages over the commonly employed approach of mass-resolved ion detection, since in general it allows the unambiguous identification of the ͑ro͒vibronic character of the excited state from which ionization took place. Put in another way, one might say that the projection of the wave function of the excited state on the ionic manifold, as done in the photoionization step, ultimately enables the reconstruction of this wave function.…”

Resonance-enhanced multiphoton ionization photoelectron spectroscopy of Rydberg states of N2O below the X 2Π ionization limit

“…In this way, a photoelectron spectrum recorded for ionization via higher-lying Rydberg states allows the direct observation of many lower-lying Rydberg states. 25,26 For instance, the photoelectron spectrum displayed in Fig. 5 shows a large part of the ͓X 2 ⌸ 3/2 ͔ns series.…”

“…25,26 A prototypical example is shown in Fig. 5, which displays the photoelectron spectrum obtained for ionization via the ͓X 2 ⌸ 3/2 ͔11s(vЈϭ0) Rydberg state.…”