The Vibrational Spectra of Molecular Ions Isolated in Solid Neon. XV. Infrared Spectroscopic Evidence for NeHF+ and HFFH+

Published

March 1, 1999

Author(s)

C Lugez, Marilyn E. Jacox, Russell D. Johnson III

Abstract

When a Ne:HF mixture is subjected to Penning ionization and/or photoionization by neon atoms in their first excited states, between 16.6 eV and 16.85 eV, and the products are rapidly frozen at approximately 5 K, the infrared spectrum of the resulting deposit includes absorptions assigned to NeHF+ and HFFH+. Evidence is presented suggesting that neon-matrix shifts may be anomalously large for protonated molecules which are derived from species with proton affinities near or below 500 kJ/mol. The results of earlier ab initio studies, as well as those of the present experimental and ab initio studies, indicate that the NeHF+ complex is quite strongly bound. The v₃ absorptions of NeHF+ and NeDF+ and the v₁ + v₃ absorption of NeHF+ are tentatively identified. An absorption at 3064.7 cm-1 has isotopic substitution behavior appropriate for its assignment to HFFH+. Density functional calculations were performed in order to estimate the positions of the harmonic vibrational fundamentals of HFFH+-d_n, and a more elaborate two-dimensional calculation on the HF-stretching potential surface was conducted in an attempt to take into account the large anharmonic contribution. Processes which occur on ultraviolet irradiation of the deposit are considered.

Citation

Journal of Chemical Physics

Volume

110

Issue

No. 11

Pub Type

Journals

Keywords

ab initio calculations, density functional calculations, HF, HFFH+, infrared spectrum, NeHF+, neon matrix, Penning ionization, photoionization

Citation

Lugez, C. , Jacox, M. and Johnson, R. (1999), The Vibrational Spectra of Molecular Ions Isolated in Solid Neon. XV. Infrared Spectroscopic Evidence for NeHF+ and HFFH+, Journal of Chemical Physics (Accessed December 16, 2024)