Showing papers by "Richard J. Saykally published in 1990"
TL;DR: Treatment of C60 with osmium tetroxide and pyridine gives the osmate ester (2:1 adduct) establishing that oxygen functionality can be added to C60 without disrupting the carbon framework.
Abstract: Treatment of C60 with osmium tetroxide and pyridine gives the osmate ester (2:1 adduct) establishing that oxygen functionality can be added to C60 without disrupting the carbon framework.
179 citations
TL;DR: In this paper, direct optical absorption measurements of jet-cooled metal clusters formed in a pulsed molecular beam have been made using a sensitive new absorption technique employing pulsed laser sources.
132 citations
TL;DR: Seven rovibrational transitions of the (01(10) <-- (00(0)0) fundamental bending band of C3 have been measured with high precision with the use of a tunable far-infrared laser spectrometer, providing the basis for studies of C 3 in the interstellar medium with far- Infrared astronomy.
Abstract: Seven rovibrational transitions of the (01/1/0)-(00/0/0) fundamental bending band of C3 have been measured with high precision with the use of a tunable far-infrared laser spectrometer. The C3 molecules were produced by laser vaporization of a graphite rod and cooled in a supersonic expansion. The astrophysically important nu-2 fundamental frequency is determined to be 63.416529(40)/cm. These measurements provide the basis for studies of C3 in the interstellar medium with far-infrared astronomy.
104 citations
TL;DR: In this paper, the fundamental van der Waals stretching vibration was measured and a transition from the lowest excited internal rotor state Σ(101,vs=0) to the highest-excited internal rotor states was investigated.
Abstract: Measurements of the fundamental van der Waals stretching vibration Σ(000,vs=1) ←Σ(000,vs=0) of Ar–H2O [ν0=907 322.08(94) MHz] and a transition from the lowest excited internal rotor state Σ(101,vs=0) to the Σ(101,vs=1) level [ν0=1019 239.4(1.0) MHz] are presented. A simultaneous rotational analysis of the new stretching data with the internal rotor bands observed by us previously [J. Chem. Phys. 89, 4494 (1988)], including the effects of Coriolis interactions, provides experimental evidence for the new assignment of the internal rotor transitions suggested by Hutson in the accompanying paper. Fits to the rotational term values for the vs=0 states are used to derive effective radial potential energy surfaces for each of the Σ internal rotor states. The results show the well depth (153.4 cm−1) of the effective radial potential for the Σ(101,vs=0) level to be approximately 25 cm−1 deeper than that for the Σ(000,vs=0) ground state of the complex, indicating that the former is stabilized considerably more by t...
77 citations
TL;DR: The first structural characterization of C9, the largest cluster predicted to have a linear ground state, is announced and the molecule is found to have unusually large ground-state and upper-state distortion constants, and several discrete perturbations are observed in the upper state.
Abstract: The high resolution infrared spectrum of the C9 cluster has been measured in direct absorption by infrared diode laser spectroscopy of a pulsed supersonic carbon cluster jet. Fifty‐one rovibrational transitions have been assigned to the ν6 (σu ) antisymmetric stretch fundamental of the 1Σ+9 linear ground state of C9. The measured rotational constant [429.30(50) MHz] is in good agreement with ab initio calculations and indicates an effective bond length of 1.278 68(75) A, consistent with cumulenic bonding in this cluster. Several perturbations are observed in the upper state, and the upper‐ and lower‐state centrifugal distortion constants are observed to be anomolously large, evidencing a high degree of Coriolis mixing of the normal modes.
57 citations
TL;DR: In this paper, the authors employed direct laser absorption spectroscopy in fast ion beams for the determination of absolute integrated band intensities (S0v) for the ν3 fundamental bands of H3O+ and NH+4.
Abstract: The technique of direct laser absorption spectroscopy in fast ion beams has been employed for the determination of absolute integrated band intensities (S0v) for the ν3 fundamental bands of H3O+ and NH+4. In addition, the absolute band intensities for the ν1 fundamental bands of HN+2 and HCO+ have been remeasured. The values obtained in units of cm−2 atm−1 at STP are 1880(290) and 580(90) for the ν1 fundamentals of HN+2 and HCO+, respectively; and 4000(800) and 1220(190) for the ν3 fundamentals of H3O+ and NH+4, respectively. Comparisons with ab initio results are presented.
54 citations
TL;DR: The observation and characterization of the C7 cluster and analysis of the spectrum indicate an effective average bond length of 1.2736(4) angstroms and a vibrational frequency of 2138.1951(10) reciprocal centimeters, in excellent agreement with ab initio calculations.
Abstract: Observation and characterization of the C7 cluster are reported. Carbon clusters are produced by laser vaporization of a graphite target followed by supersonic expansion of the vaporized material within a gas dynamically focused argon jet. Thirty-six sequential rovibrational lines of the nu 4 antisymmetric stretch fundamental of C7 are probed by gated detection of diode laser absorption. The observed spectrum is characteristic of a symmetrical linear molecule. Analysis of the spectrum indicates an effective average bond length of 1.2736(4) angstroms and a vibrational frequency of 2138.1951(10) reciprocal centimeters, in excellent agreement with ab initio calculations. This work will facilitate the astrophysical detection of this cluster.
51 citations
TL;DR: In this article, a nearly free rotor model is used to deduce the zeroth-order intermolecular vibrational energy-level diagram and corresponding selection rules, which are used in assigning the spectra.
Abstract: Hyperfine resolved spectra have been measured for the Ar-NH3 complex over the range 21–28 cm-1 using a tunable far-infrared laser in combination with a continuous planar supersonic jet. Twenty-three transitions are assigned to the lowest Σ-bending vibration (v 0 = 26·470633(77)cm-1) from the (asymmetric) inversion level of the Σ, j k c = 00 internal rotor state of NH3 to the Σ, (10) symmetric inversion level. A nearly free-rotor model is used to deduce the zeroth-order intermolecular vibrational energy-level diagram and corresponding selection rules, which are used in assigning the spectra. All evidence obtained in this study supports the contention of Nelson et al. that NH3 is an inverting nearly free rotor in this T-shaped complex.
29 citations
TL;DR: In this paper, an efficient separatory technique is described which implements a phenylglycine based HFLC column for preparation of high purity (99.99%) C60 and C70 samples.
Abstract: An extremely simple and inexpensive apparatus for preparation of the C60 and C70 fullerenes is described. An efficient separatory technique is described which implements a phenylglycine based HFLC column for preparation of high purity (99.99%) C60 and C70 samples. Treatment of C60 with osmium tetroxide and pyridine gives the osmate ester (2:1 adduct) and establishes that oxygen functionality can be added to C60 without disrupting the carbon framework. Raman spectroscopy of high purity C60 indicates that several lines previously not assigned to C60 (D.S.Bethune, G.Meijer, W.C.Tang, and H.J.Rosen, Chem.Phys.Lett.174, 219(1990)) are attributable to C60.
1 citations
01 Jan 1990
TL;DR: In this article, a nearly free rotor model is used to deduce the zeroth-order intermolecular vibrational energy-level diagram and corresponding selection rules, which are used in assigning the spectra.
Abstract: Hyperfine resolved spectra have been measured for the Ar-NH3 complex over the range 21-28 cm -~ using a tunable far-infrared laser in combination with a continuous planar supersonic jet. Twenty-three transitions are assigned to the lowest E-bending vibration (v0 = 26.470633(77)cm 1) from the (asymmetric) inversion level of the E, jk c = 00 internal rotor state of NH3 to the E, (10) symmetric inversion level. A nearly free-rotor model is used to deduce the zeroth-order intermolecular vibrational energy-level diagram and corresponding selection rules, which are used in assigning the spectra. All evidence obtained in this study supports the contention of Nelson et al. that NH3 is an inverting nearly free rotor in this T-shaped complex.