Dissociation energy of neutral and ionic benzene-noble gas dimers by pulsed field threshold ionization spectroscopy

Abstract

Delayed pulsed field threshold ionization of clusters excited to high long-lived Rydberg states is used to study their dissociation behavior. Benzene–Ar and benzene–Kr dimers are excited by resonance enhanced two-photon ionization to Rydberg levels close to various ionization thresholds. The field ionized threshold ions are monitored and separated from the non-energy-selected ions in a reflecting field mass spectrometer with high mass resolution. The appearance of threshold ions at the daughter ion mass indicates the onset of a dissociation process. Daughter ions are first observed for the 16161(3/2) level of the two investigated dimers. This leads to an upper limit of the dissociation energy of benzene–Ar of 340 cm−1 which is probably higher than the true dissociation energy. For the first time threshold ions are observed for large internal energies of some 5 eV in the core indicating that high Rydberg states maintain their long lifetime even if the core is electronically or vibrationally excited by several eV.

The infrared spectrum of the benzene–Ar cation

“…This is substantiated by the good agreement between the observed MATI spectra for bare benzene and those of its argon complexes. 10 The experimental setup and the detection method that is used are similar to those described previously in our work reporting on the IR spectra of aniline-Ar, 13 naphthaleneAr, 14 and pyrazine-Ar, 15 and are only briefly given here. The experiments are performed using the free electron laser for infrared experiments ͑FELIX͒ 16 as a source of intense pulsed infrared radiation.…”

“…3,4 Its low fluorescence quantum yield has prohibited such gas-phase LIF studies on the benzene cation. Photoelectron spectroscopy 5 and threshold-electron ͑zero electron kinetic energy, ZEKE͒ [6][7][8] and threshold-ion detection ͑mass analyzed threshold ionization, MATI͒ schemes [9][10][11] have been successfully used, however, to measure and assign several vibrational modes in the benzene cations.…”

A Systematic CCSD(T) Study of Long-Range and Noncovalent Interactions between Benzene and a Series of First- and Second-Row Hydrides and Rare Gas Atoms

“…For systems where the zero-point energy has also been accurately determined, the vibrationally averaged binding energy (D 0 ) is calculated and compared with experimental results. [27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45] For clarity, the results of all previous experimental and high-level ab initio studies on benzene-small molecule systems are summarized in Table 1.…”

Diagnostics and analyses of decay process in laser produced tetrakis(dimethyl-amino)ethylene plasma

“…6 For some of them, the lifetime can be hundreds of nsec, even tens of sec, and the most prominent example is C 60 . 14,15 There are also many reports for other molecules such as benzene, [16][17][18][19] benzene clusters, 20,21 benzene-noble gas dimers, 22 naphthalene, 23 azulene, 24 triethylamine, 25 ketene, 26 Nb, Ta, and W clusters, 27,28 C 70 , 14,29 fullerenes C n (nϽ96), 30 etc. There are many theoretical articles, too.…”