Near dissociation states for H₂⁺–He on MRCI and FCI potential energy surfaces

Abstract

A new analytical potential energy surface (PES) has been constructed for H + 2 -He using a reproducing kernel Hilbert space (RKHS) representation from an extensive number of ab initio energies computed at the multi-reference and full configuration interaction level of theory. For the MRCI PES the long-range interaction region of the PES is described by analytical functions and is connected smoothly to the shortrange interaction region, represented as a RKHS. All ro-vibrational states for the ground vibrational and electronic state of H + 2 -He are calculated using two different methods to determine quantum bound states. Comparing transition frequencies for the near-dissociation states for ortho-and para H + 2 -He allows assignment of the 15.2 GHz line to a J = 2 e/f parity doublet of ortho-H + 2 -He whereas the experimentally determined 21.8 GHz line is only consistent with a (J = 0) → (J = 1) e/e transition in para-H + 2 -He. a) m.meuwly@unibas.ch

Accurate reproducing kernel-based potential energy surfaces for the triplet ground states of N2O and dynamics for the N + NO ↔ O + N2and N2+ O → 2N + O reactions

“…36 and 52 and has also been used to construct PESs for other triatomic systems. [37][38][39] Fig. 1 Schematic energy diagram for the N 2 O system showing different reactant channels, minima (MIN i) and transition states (TS i).…”

“…On the other hand the reproducing kernel Hilbert space (RKHS) interpolation procedure can capture the correct long range behavior for different types of interactions. [36][37][38][39] Another relevant quantity that balances the energy content of hot gas flow is the exchange and relaxation of vibrational energy which can also be determined from QCT simulations. 40,41 This property has been found to be sensitive to different regions of the PES than reaction rates 39 and provides an additional possibility to validate the quality of the PESs.…”

Cationic Noble-Gas Hydrides: From Ion Sources to Outer Space

“…Illustrative in this regard are, for example, the extensive studies on the reaction between H + 2 and He performed so far by Herman, Zülicke, and their coworkers (Schneider et al, 1976;Havemann et al, 1978, and references cited therein) with crossedbeam experiments and quasi-classical trajectory calculations. The NgH + 2 possess linear Ng-H-H + connectivities, and their potential wells (see Table 1) are deep enough Koner et al, 2019) to sustain numerous vibrational and rovibrational states. The latter were accurately estimated even recently Papp et al, 2017Papp et al, , 2018Szidarovszky and Yamanouchi, 2017), also in the intriguing prospect of actual detection of natural NgH + 2 .…”

Rotational action spectroscopy of trapped molecular ions

“…The latter three complexes are interesting, as they are floppy, consist of only hydrogen and helium atoms, and are thus fundamental few-electron systems. For H 2 -He, although being a fundamental three-electron system, only difficult-to-assign microwave spectra close to the dissociation limit exist 118,119 , as well as ab initio data for its rovibrational levels 115,116,120 . This ion may have played an important role in the early universe, and it still plays an important role in astrochemistry as the intermediate collision complex in the fundamental He − H + 2 scattering process.…”