Direct measurement of bending conformations in triatomic dihydride ions

Journal Article · Wed Oct 01 04:00:00 EDT 1997 · Physical Review A

DOI:https://doi.org/10.1103/PhysRevA.56.2600· OSTI ID:633980

Graber, T; Kanter, E P ^[1]; Levin, J; Zajfman, D; Vager, Z ^[2]; Naaman, R ^[3]

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1. Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States)
2. Department of Particle Physics, Weizmann Institute of Science, Rehovot 76 100 (Israel)
3. Department of Chemical Physics, Weizmann Institute of Science, Rehovot 76 100 (Israel)

The distributions of bond angles in the triatomic dihydride ion series CH{sub 2}{sup +}, NH{sub 2}{sup +}, and H{sub 2}O{sup +} have been studied using the Coulomb explosion imaging method. These distributions were measured as a function of the cooling of the internal degrees of freedom of these ions. The distribution for the coldest sample of CH{sub 2}{sup +} molecules shows the most probable structure to be bent with substantial tunneling through the linear conformation. The most probable geometry for NH{sub 2}{sup +} was found to be linear, though the angular distribution is significantly different from a shape of a harmonic-oscillator ground-state prediction. In the case of H{sub 2}O{sup +}, we find a bent structure as expected from theory. Evidence for a linear excited state in H{sub 2}O{sup +} is seen in the hotter distributions. Comparison to the adiabatic theoretical predictions shows good agreement with the most probable geometries. However, the measured distributions are systematically wider than the squared vibronic wave functions derived from the corresponding potential-energy surfaces. {copyright} {ital 1997} {ital The American Physical Society}

• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 633980
• Journal Information: Physical Review A, Journal Name: Physical Review A Journal Issue: 4 Vol. 56; ISSN PLRAAN; ISSN 1050-2947
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
BENDING
BOND ANGLE
CARBON COMPOUNDS
CATIONS
DISSOCIATION
GROUND STATES
HARMONIC OSCILLATORS
HYDRIDES
MOLECULAR IONS
NITROGEN COMPOUNDS
ORGANIC COMPOUNDS
VIBRATIONAL STATES
WATER