High-resolution measurement of the infrared rotation-vibration spectrum of the negative molecular ion /sup 14/NH/sup -/

Journal Article · Sun Feb 01 04:00:00 EST 1987 · Phys. Rev. A; (United States)

DOI:https://doi.org/10.1103/PhysRevA.35.1099· OSTI ID:5895336

Al-Za'al, M; Miller, H C; Farley, J W

The authors have performed an extensive series of measurements of the infrared rotation-vibration spectrum of the negative molecular ion /sup 14/NH/sup -/. A total of 114 transitions in the P, Q, and R branches of the fundamental band near 3000 cm/sup -1/ have been measured with an accuracy (1 standard deviation) of 0.01 cm/sup -1/. The resolution is much higher (7 MHz), enabling us to resolve hyperfine structure. Autodetachment linewidths have also been measured. The electron affinity of NH has been measured with a precision a thousand times higher than previous work: E/sub EA/(NH) = 0.374 362 +- 0.000 005 eV. Our data agree with earlier measurements of the R branch and include the first high-resolution measurements of the Q and P branches. We have observed rotationally excited metastable states as much as 1.8 eV above the autodetachment threshold. A least-squares fit to the transition frequencies has been performed, using an effective Hamiltonian with a sextic term. The predictions of the best previous work, extrapolated to high J, disagree by as much as 10 cm/sup -1/, or one thousand times the experimental uncertainty. This paper more than doubles the number of measured transition frequencies in this species.

• Research Organization: Physics Department and Chemical Physics Institute, University of Oregon, Eugene, Oregon 97403
• OSTI ID: 5895336
• Journal Information: Phys. Rev. A; (United States), Journal Name: Phys. Rev. A; (United States) Vol. 35:3; ISSN PLRAA
• Country of Publication: United States
• Language: English

Related Subjects

640302* -- Atomic
Molecular & Chemical Physics-- Atomic & Molecular Properties & Theory
74 ATOMIC AND MOLECULAR PHYSICS
AFFINITY
ANIONS
CHARGED PARTICLES
ENERGY LEVELS
ENERGY RESOLUTION
ENERGY-LEVEL TRANSITIONS
EXCITED STATES
HYDRIDES
HYDROGEN COMPOUNDS
INFRARED SPECTRA
IONS
LINE WIDTHS
MOLECULAR IONS
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
RESOLUTION
ROTATIONAL STATES
SPECTRA
VIBRATIONAL STATES