Vibrational-rotational spectroscopy of the hydrated hydronium ions H[sub 5]O[sub 2][sup [plus]] and H[sub 9]O[sub 4][sup [plus]]
- Univ. of California, Berkeley, CA (United States). Dept. of Chemistry Lawrence Berkeley Lab., Berkeley, CA (United States). Materials and Chemical Sciences Div.
- National Inst. of Standards and Technology, Gaithersburg, MD (United States). Molecular Physics Div.
High-resolution vibration-rotation spectra in the OH antisymmetric stretching region near 3,700 cm[sup [minus]1] are reported for H[sub 5]O[sub 2][sup +] and H[sub 9]O[sub 2][sup +]. Spectroscopic interrogation using a two-color laser scheme leads to rovibrational excitation of the trapped ions followed by preferential multiphoton dissociation of the vibrationally excited ions and detection of the resultant fragment ions. Many more lines appear in the partially resolved vibration-rotation spectrum of H[sub 5]O[sub 2][sup +] than can be explained if the molecule is rigid, and the authors have assumed that these additional lines arise from tunneling splittings caused by large-amplitude internal motions in this ion. Despite the low signal-to-noise ratio, all the observed spectral features can be grouped into roughly 12 R branches with a line spacing only 14% less than the B + C value calculated from the ab initio structure. Theoretically expected splitting patterns were calculated using a formalism developed earlier for tunneling motions in hydrazine. The authors tentatively conclude that the 12 branches represent the overlapping of six tunneling-split components for the in-phase and six for the out-of-phase OH antisymmetric stretching vibrations expected in this region, but the low signal-to-noise ratio in the present measurements prevented unambiguous comparison of theory and experiment.
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 7041907
- Journal Information:
- Journal of Molecular Spectroscopy; (United States), Vol. 164:2; ISSN 0022-2852
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
OXONIUM IONS
SPECTROSCOPY
CATIONS
EXPERIMENTAL DATA
MULTI-PHOTON PROCESSES
ROTATIONAL STATES
VIBRATIONAL STATES
CHARGED PARTICLES
DATA
ENERGY LEVELS
EXCITED STATES
INFORMATION
IONS
MOLECULAR IONS
NUMERICAL DATA
664200* - Spectra of Atoms & Molecules & their Interactions with Photons- (1992-)