Universität zu Köln

Salomon, Thomas, Brackertz, Stefan ORCID: 0000-0001-6618-092X, Asvany, Oskar, Savic, Igor ORCID: 0000-0002-9954-7457, Gerlich, Dieter, Harding, Michael E., Lipparini, Filippo ORCID: 0000-0002-4947-3912, Gauss, Juergen, van der Avoird, Ad ORCID: 0000-0003-1856-240X and Schlemmer, Stephan ORCID: 0000-0002-1421-7281 (2022). The He-H-3(+) complex. II. Infrared predissociation spectrum and energy term diagram. J. Chem. Phys., 156 (14). MELVILLE: AIP Publishing. ISSN 1089-7690

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Abstract

The rotationally resolved infrared (IR) spectrum of the He-H-3(+) complex has been measured in a cryogenic ion trap experiment at a nominal temperature of 4 K. Predissociation of the stored complex has been invoked by excitation of the degenerate nu(2) mode of the H-3(+) sub-unit using a pulsed optical parametric oscillator system. An assignment of the experimental spectrum became possible through one-to-one correlations with bands of the spectrum theoretically predicted in Paper I [Harding et al., J. Chem. Phys. 156, 144307 (2022)]. 19 bands have been assigned and analyzed, and the energy term diagram of the lower states of this floppy molecular complex has been derived from combination differences (CDs) in the experimental spectrum. Ground state combination differences (GSCDs) reveal a large part of the energy term diagram for the He-H-3(+) complex in its vibrational ground state, v = 0. Experimental and theoretical term energies agree within experimental accuracy for the rotational fine structure associated with the total angular momentum quantum number J and the parity e/f as well as for the coarse spacing of the lowest K states of the complex. This favorable comparison shows that the potential energy surface (PES) calculated in Paper I is accurate. The barriers between the three equivalent global minima in this PES are relatively low and the He-H-3(+) complex is extremely floppy, with nearly unhindered internal rotation of the H-3(+) sub-unit. The resulting Coriolis interactions couple the internal and end-over-end rotation of the complex and contribute significantly to the energy terms. They are observed both in experiment and theory and are, e.g., the origin of different rotational constants for states of e and f parity. Also in this respect, experiment and theory agree very well. Despite the assignment and analysis of many bands of the extremely rich IR spectrum of H-3(+), higher levels of excitation, including the complex stretching mode, need further attention. Published under an exclusive license by AIP Publishing.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Salomon, Thomas UNSPECIFIED UNSPECIFIED UNSPECIFIED Brackertz, Stefan UNSPECIFIED orcid.org/0000-0001-6618-092X UNSPECIFIED Asvany, Oskar UNSPECIFIED UNSPECIFIED UNSPECIFIED Savic, Igor UNSPECIFIED orcid.org/0000-0002-9954-7457 UNSPECIFIED Gerlich, Dieter UNSPECIFIED UNSPECIFIED UNSPECIFIED Harding, Michael E. UNSPECIFIED UNSPECIFIED UNSPECIFIED Lipparini, Filippo UNSPECIFIED orcid.org/0000-0002-4947-3912 UNSPECIFIED Gauss, Juergen UNSPECIFIED UNSPECIFIED UNSPECIFIED van der Avoird, Ad UNSPECIFIED orcid.org/0000-0003-1856-240X UNSPECIFIED Schlemmer, Stephan UNSPECIFIED orcid.org/0000-0002-1421-7281 UNSPECIFIED
URN:	urn:nbn:de:hbz:38-688162
DOI:	10.1063/5.0087427
Journal or Publication Title:	J. Chem. Phys.
Volume:	156
Number:	14
Date:	2022
Publisher:	AIP Publishing
Place of Publication:	MELVILLE
ISSN:	1089-7690
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language ROTATIONAL SPECTROSCOPY; WAVE SPECTROSCOPY; ARH3+ Multiple languages Chemistry, Physical; Physics, Atomic, Molecular & Chemical Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/68816