Multiphoton spectroscopy of NO–Rg (Rg = rare gas) van der Waals systems

Abstract

The spectroscopic characterization of the electronic ground and excited state interactions of NO with diOE erent rare gases is reviewed. In its electronic ground state, the NO molecule continues to serve as one of the most important benchmark systems for investigating van der Waals interactions involving open shell molecules. Combining high resolution infrared excitation with resonance enhanced multiphoton ionization (REMPI) detection, bound intermolecular bend± stretch levels have been detected for the complexes NO± Ar and NO± Ne for the ® rst time.In parallel with these new experimental advances, new high-level ab-initio potential energy surfaces have been calculated very recently for several NO± Rg (Rgˆrare gas) systems. Predictions for the bound states based on these potentials are in excellent agreement with the high resolution infrared spectra for NO± Ar and NO± Ne, demonstrating the great accuracy achieved with current ab initio methods. The large number of excited electronic states of NO provides ideal opportunities for studying molecular interactions in diOE erent excited states. The low lying Rydberg states are especially interesting because the Rydberg electron can reside in an orbital whose size is comparable with or larger than the van der Waals radius of the complexed atom. The existing set of experimental data on Rydberg states with nˆ3…lˆ0; 1; 2 † and nˆ4…lˆ0 † are reviewed critically. The excited states have been investigated employing mainly REMPI spectroscopy. The data provide detailed information about the bound levels of the associated intermolecular surfaces. Most of the work has concentrated on the complexes with Ar and Ne. Additional data for the statesà A 2 § andC C 2 ¦ are available for complexes with Kr and Xe.

The water-nitric oxide intermolecular potential-energy surface revisited

“…Nitric oxide ͑NO͒ is one of the most important molecules to study van der Waals interactions in open-shell systems. Many papers have been devoted to investigations regarding the spectroscopy and nature of the interactions between NO and rare gases [6][7][8][9][10][11][12][13][14] or small molecules. 15,16 Intermolecular potential-energy surfaces ͑IPESs͒ were reported for the interaction of NO with several small molecules, e.g., N 2 , CO, CH 4 , and C 2 H 6 .…”

The binding energies of NO–Rg (Rg = He, Ne, Ar) determined by velocity map imaging

“…These were summarised by Kim and Meyer in their 2001 review of the multiphoton spectroscopy of the NO-Rg complexes. 2 A recent overview is given by Klos et al 3 Comparison with experiment is crucial for establishing the suitability of different ab initio approaches. However, experimental measurements of the dissociation energies have not been reported for NO-He, -Ne and the value for NO-Ar has recently been called into question.…”

“…1,2 The small number of electrons associated with He and Ne makes the dispersion interactions in the NO-He and NO-Ne systems particularly weak, especially in the case of He, and sophisticated calculations are required for accuracy. These systems thus provide excellent test cases for high level calculations.…”

Spectroscopy of free radicals and radical containing entrance-channel complexes in superfluid helium nanodroplets

“…The most common examples are X-HY radicals, where X are, for example, H 2 or noble gas atoms and Y=C, O, N, S, B, or CN radicals. Many of the previous experiments have been performed using an noble-gas atom such as argon or neon to study the effects of polarization, and in these cases no reaction can occur [39,40]. Complexes have also been observed between reactive partners such as, for example, OH+CO [41], OH+H 2 [42][43][44][45][46], and CN+H 2 [47][48][49][50].…”