Showing papers by "Richard J. Saykally published in 1989"
TL;DR: In this article, Coudert and Hougen proposed a local IAM model for the hydrogen bond tunneling dynamics of the water dimer, which includes four different tunneling motions and contributes to the observed tunneling splittings.
Abstract: Fifty-six transitions from the K=1 lower-->K=2 lower tunneling–rotation band of water dimer have been measured and assigned at 22 cm^–1 by direct absorption spectroscopy in a cw planar supersonic jet expansion using a tunable far infrared laser spectrometer. Two different models were used to fit the data and several spectroscopic constants were determined for the upper and lower states. This work supports the local IAM model recently proposed by Coudert and Hougen for the hydrogen bond tunneling dynamics of the water dimer. This model includes four different tunneling motions, all of which contribute to the observed tunneling splittings. This is the most complicated hydrogen bonded system considered to be well understood at this time, at least in the lowest few K states.
105 citations
TL;DR: This work confirms the detection of C5 in IRC + 10216 reported in the accompanying paper, in good agreement with ab initio quantum chemical calculations.
Abstract: A new spectroscopic experiment has been developed in which rovibrational transitions of supersonically cooled carbon clusters, which were produced by laser vaporization of graphite, have been measured by direct-absorption diode-laser spectroscopy. Thirty-six sequential rovibrational lines of the nu 3 band of the C5 carbon cluster have been measured with Doppler-limited resolution. The absorption spectrum is characteristic of a linear molecule with a center of symmetry. Least-squares analysis of the spectrum indicates an effective carbon-carbon bond length of 1.283 angstroms, in good agreement with ab initio quantum chemical calculations. This work confirms the detection of C5 in IRC + 10216 reported in the accompanying paper.
78 citations
TL;DR: In this article, a new technique called direct laser absorption spectroscopy in fast ion beams (DLASFIB) was proposed for measuring vibration-rotation spectra of molecular ions with sub-Doppler resolution and accurate determination of the mass and number density of the carriers of all spectral features.
Abstract: We report the development of a new general technique for measuring vibration–rotation spectra of molecular ions with sub‐Doppler resolution and with accurate determination of the mass and number density of the carriers of all spectral features. With this method, called direct laser absorption spectroscopy in fast ion beams (DLASFIB), we have carried out the first observation of direct absorption of photons by ions in a fast ion beam. Hyperfine‐resolved vibration–rotation transitions of HF+ have been measured, and along with optical combination differences and laser magnetic resonance data, have been analyzed to yield the fluorine hyperfine parameters a, b, c and d for both v=0 and v=1 in the X 2Π state. Comparisons with many‐body perturbation theory results are presented.
46 citations
TL;DR: In this article, a detailed characterization of the structures and internal dynamics of weakly bound complexes is provided, as the first step toward the ultimate goal of obtaining details three-dimensional intermolecular potential energy surfaces for molecular weak interactions.
Abstract: Our objective in these studies is to provide a detailed characterization of the structures and internal dynamics of weakly bound complexes as the requisite first step toward the ultimate goal: obtaining details three-dimensional intermolecular potential-energy surfaces for molecular weak interactions. The current state of the art limits us to studies of binary systems, but several groups are currently seeking to extend both the theory and experiments to address ternary and quaternary complexes. This will afford a detailed examination of the many-body effects (e.g., Axelrod -Teller triple dipole dispersion interaction), which becomes of potential importance in models of the chemistry of liquids.
44 citations
TL;DR: In this article, an improved value for the dipole moment of ArH^+ was obtained from new measurements of the rotational g factors of ARH+ and ArD^+ made with tunable far-IR laser spectroscopy.
Abstract: An improved value for the dipole moment of ArH^+ has been obtained from new measurements of the rotational g factors of ArH^+ and ArD^+ made with tunable far‐IR laser spectroscopy. Systematic errors present in earlier measurements have been eliminated. The new result (μ=3.0±0.6 D) is slightly higher than the ab initio value of Rosmus (2.2 D) at the 2σ limits of precision.
34 citations
TL;DR: In this article, the authors measured 62 lines in the v 4 band of the ammonium ion (NH4 +) using infrared diode laser velocity modulation spectroscopy of a hydrogen/ammonia discharge.
Abstract: We have measured 62 lines in the v 4 band of the ammonium ion (NH4 +) using infrared diode laser velocity modulation spectroscopy of a hydrogen/ammonia discharge. The transitions were fitted to a fourth order spherical rotor hamiltonian yielding v 4 = 1447·2158(50) cm-1, B 4 = 5·85121(24) cm-1 and 2B 4ζ4 = 5·3757(11) cm-1. As in methane, the v 4 band is strongly perturbed by the higher frequency v 2 band. A comparison of the measured molecular properties with ab initio calculations is given.
33 citations
TL;DR: In this article, the absolute integrated band intensities (S{sub v}{sup 0}) for the {nu}{sub 1} fundamental bands of HN{sub 2} and HCO{sup +} were determined by the recently developed technique of direct laser absorption spectroscopy in fast ion beams.
Abstract: The authors report the determination of absolute integrated band intensities (S{sub v}{sup 0}) for the {nu}{sub 1} fundamental bands of HN{sub 2}{sup +} and HCO{sup +} by the recently developed technique of direct laser absorption spectroscopy in fast ion beams. The values obtained for HN{sub 2}{sup +} (1,250 (300) cm{sup {minus}2} atm{sup {minus}1}) and HCO{sup +} (430 (100) cm{sup {minus}2} atm{sup {minus}1}) are substantially lower than corresponding results from high level ab initio calculations.
23 citations
TL;DR: In this paper, the X2Π vibronic ground states of H35Cl+ and H37Cl+ molecular ions have been measured by far-infrared laser magnetic resonance (LMR).
23 citations
TL;DR: In this paper, Cohen, K.L. Busarow, C.A. Schmuttenmaer, Y.T. Lee, and R.J. Saykally, Chem. Phys. Lett. 164,321.
16 citations
TL;DR: A total of 468 vibration-rotation transitions have been measured and assigned to the (010)-(110), (001)-(101), (020)-(120), (030)-(130), and (000)-(100) bands of HCS +.
11 citations
TL;DR: In this paper, a weighted fit of all available high resolution data was determined for the v = 0 and v = 1 fluorine hyperfine constants (except b(1)), λ-doubling parameters, rotational and centrifugal distortion constants and the vibrational band origin).
Abstract: 34 v = 1 ← 0 R branch infrared transitions in the X 2Π state of the HF+ molecular ion have been measured by velocity modulation laser absorption spectroscopy. Fluorine hyperfine structure was resolved for low J transitions. From a weighted fit of all available high resolution data, values were determined for the v = 0 and v = 1 fluorine hyperfine constants (except b(1)), λ-doubling parameters, rotational and centrifugal distortion constants and the vibrational band origin. Molecular expectation values derived from the hyperfine constants are compared to similar quantities for OH and NH-. An analysis is presented for the v = 0 proton hyperfine structure observed previously by laser magnetic resonance.