Computational Characterization of Astrophysical Species: The Case of Noble Gas Hydride Cations

Abstract

Theoretical–computational studies together with recent astronomical observations have shown that under extreme conditions in the interstellar medium (ISM), complexes of noble gases may be formed. Such observations have generated a wide range of possibilities. In order to identify new species containing such atoms, the present study gathers spectroscopic data for noble gas hydride cations, NgH+ (Ng = He, Ne, Ar) from high-level ab initio quantum chemistry computations, aiming to contribute in understanding the chemical bonding and electron sharing in these systems. The interaction potentials are obtained from CCSD(T)/CBS and MRCI+Q calculations using large basis sets, and then employed to compute vibrational levels and molecular spectroscopic constants for all known stable isotopologues of ground state NgH+ cations. Comparisons with previously reported values available are discussed, indicating that the present data could serve as a benchmark for future studies on these systems and on higher-order cationic noble gas hydrides of astrophysical interest.

Spectral Signatures of Protonated Noble Gas Clusters of Ne, Ar, Kr, and Xe: From Monomers to Trimers

“…The predicted bond distance at this level of theory not only captures the trend, but also agrees well with the reported experimental values. Furthermore, our CCSD(T) internuclear distances have reproduced the reported calculations of Borocci et al [ 51 ] Furthermore, our calculated internuclear distances for NeH + and ArH + agrees well with those reported by de Oca-Estévez et al, which were calculated at the CCSD(T)/CBS[56] and MRCI+Q/aug-cc-pV6Z levels of theory and basis [ 31 ].…”

“…Recently, Borocci et al have examined the bonding nature of NgH + using local electron energy density [ 30 ]. Furthermore, high-level simulations at the CCSD(T) and MRCI+Q levels have been performed to calculate the vibrational spectrum and rotational constants for NgH + [ 31 ].…”

Viewpoints on the 11th International Meeting on Atomic and Molecular Physics and Chemistry

“…20 Two more hot topics followed, one by Yihui Yan describing experiments to measure sticking probabilities of organic molecules on HNO 3 clusters relevant for atmospheric chemistry 21 and another by Marı ́a Judit Montes de Oca Estevez describing her ab initio calculations combined with RHKS approach to compute precise potential energy surfaces and reproduce spectroscopic data for noble gas molecules of astrochemical relevance. 22 This talk was also one of the Best Hot Topic presentations. In his invited talk, Hans Christian Schewe reported on experimental studies of electrolyte-tometal transition in liquid alkali-metal ammonia solutions using liquid microjets and droplets in vacuum as developed in his laboratory in Prague, as well as on his recent experiments showing spectroscopic evidence of a metallic water solution.…”

“…Monday evening's session started with the hot topic of Sompriya Chatterjee showing how replica exchange molecular dynamics can be used to model processes in large biological systems; in particular, he focused on the histidine tautomerism modulated misfolding mechanism of prion protein . Two more hot topics followed, one by Yihui Yan describing experiments to measure sticking probabilities of organic molecules on HNO 3 clusters relevant for atmospheric chemistry and another by Marı́a Judit Montes de Oca Estévez describing her ab initio calculations combined with RHKS approach to compute precise potential energy surfaces and reproduce spectroscopic data for noble gas molecules of astrochemical relevance . This talk was also one of the Best Hot Topic presentations.…”

Ar+ ArH+ Reactive Collisions of Astrophysical Interest: The Case of 36Ar

“…[8,9] More recently, ArH + has been the subject of a variety of spectroscopic studies, [10][11][12][13][14][15][16][17][18] as well as its collision with electrons, H and He atoms, and H 2 , [17,[19][20][21][22] as the most common in ISM. On the one hand, some of us have recently performed high level CCSD(T)/CBS and MRCI + Q computations [18,23] provided new interaction energy potentials, bound states for 36 Ar/ 38 Ar/ 40 ArH/D + isotopic species, and relevant spectroscopic constants. On the other hand, the reactive scattering of the ArH + + Ar!Ar + ArH + proton exchange reaction has been recently studied by means of exact quantum-mechanical (QM), both time-dependent and timeindepedent, dynamics simulations, and quasi-classical trajectory (QCT) calculations using a new CCSD(T)-based potential energy surface (PES) of the Ar 2 H + system.…”