200 research outputs found
ZEKE-PFI SPECTROSCOPY OF THE SODIUM-WATER AND SODIUM-AMMONIA DIMERS
No full textAuthor Institution: Division of Geological and Planetary Sciences, California institute of TechnologySingle-photon ZEKE-PFI experiments have been performed on the , , , and clusters in a molecular beam, and two photon ZEKE-PFI experiments have been performed on the and clusters. From the single photon spectra the ionization potentials and intermolecular streching vibrational frequencies of the cluster ions have been determined, as well as the changes in the intermolecular bending vibrational frequencies upon ionization. The intermolecular bending vibrational frequencies of the and cluster ions were obtained from the two-photon ZEKE-PFI spectra. Partially resolved rotational structure in the spectra will be discussed
ZERO ELECTRON KINETIC ENERGY PULSED FIELD IONIZATION (ZEKE) SPECTROSCOPY OF AND
No full textAuthor Institution: Laser Spectroscopy Facility, Department of ChemistryThe two-color REMPI and ZEKE spectra of the and radicals have been obtained. The radicals were generated in a supersonic free jet expansion by ArF excimer photolysis of while was generated by ablation of a Mg rod in the presence of a methyl source, generally either or . The ZEKE spectra, taken via various intermediate vibronic levels of the state, are used to reveal the vibrational structure of the and cations and to measure the adiabatic ionization energy for each radical. These radicals belong to the point group and are therefore subject to a Jahn-Teller interaction in the state, which allows a broader range of vibrational states to be accessible in the LIF and REMPI experiments, thereby enabling access to a broader range of vibrational states for the ions in the ZEKE experiment. Vibrational frequencies and assignments of the ions will be reported
ZERO ELECTRON KINETIC ENERGY PULSED FIELD IONIZATION (ZEKE) SPECTROSCOPY OF AND
No full textAuthor Institution: Laser Spectroscopy Facility, Department of Chemistry, The Ohio State UniversityThe two-color (1+1)REMPI and ZEKE spectra of the and radicals are reported for the first time. Based upon the observed intensities in the ZEKE spectrum for , via traditions to different vibrational levels of the intermediate state, the bund previously assigned as the upper spin-orbit component of the vibrationless level of the transition in neutral is reassigned. This band which has now been observed in both LIF and REMPI experiments, is reassigned as the band of the lower spin-orbit component, . The ZEKE spectra, taken via various intermediate rovibronic levels, are used to reveal rovibrational structure of the and cations and to measure the adiabatic ionization energies for both radicals. These radicals belong to the , point group and are therefore subject to a Jahn-Teller interaction in the state, which allows a broader range of {K^{\prime}} states to be accessible in the LIF and REMPI experiments thereby enabling access to a broader range of K states for the ions in the ZEKE experiment. The resolved K structure in the level with one quanta of excitation in the ion enables estimates of both the rotational constant A and the coriolis coupling constant to be made. Vibrational frequencies and assignments for the ions will be reported
SYMMETRIC ROTOR LINE STRENGTH FACTORS IN ZEKE-PFI SPECTRA
No full text S.I. Panov, David E. Powers and T.A. Miller J. Chem. Phys. 108 1335 (1998). Klaus M\""{u}ller-Dethlefs J. Chem. Phys. 95 4821 (1991).Author Institution: Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA; Laser Spectroscopy Facility, Department of Chemistry, The Ohio State University, Columbus, OHIn the two color ZEKE-PFI of the radical well-resolved K rotational structure has been observed in some vibronic states. We have extended the previous theoretical formulation of the selection to cover the observed transitions. An important result is that the selection rules are determined by the vibronic structure of the intermediate state of the neutral from which the ionizing ZEKE transition occurs. For example, the H\""{o}nl-London-type line strength factor S for the ionizing vibronic transition can be written as where p denotes the state's parity and the are determined by the wavepacket composition of the Rydberg state that is subsequently field ionized. The are coefficients in an expansion of the neutral state's vibronic wavefunction in terms of a core wavefunction , its vibrational wavefunctions , and its single electron atomic wavefunctions : $|\phi\rangle=|\phi_{cor}\rangle \sum\limits_{l_{A},\lambda_{A}} a_{l_{A} \lambda_{A} |\phi_{vib}}\rangle |l_{A}, \lambda_{A}\rangle
Charmonium decays of Y(4260), psi(4160), and psi(4040)
No full textUsing data collected with the CLEO detector operating at the CESR e(+)e(-) collider at root s = 3.97-4.26 GeV, we investigate 15 charmonium decay modes of the psi(4040), psi(4160), and Y(4260) resonances. We confirm, at 11 sigma significance, the BABAR Y(4260)->pi(+)pi(-)J/psi discovery, make the first observation of Y(4260)->pi(0)pi(0)J/psi (5.1 sigma), and find the first evidence for Y(4260)-> K(+)K(-)J/psi (3.7 sigma). We measure e(+)e(-) cross sections at root s=4.26 GeV as sigma(pi(+)pi(-)J/psi)=58(-10)(+12)+/- 4 pb, sigma(pi(0)pi(0)J/psi)=23(-8)(+12)+/- 1 pb, and sigma(K(+)K(-)J/psi)=9(-5)(+9)+/- 1 pb, in which the uncertainties are statistical and systematic, respectively. Upper limits are placed on other decay rates from all three resonances
Dielectron widths of the Upsilon(1S,2S,3S) resonances
No full textWe determine the dielectron widths of the Upsilon(1S), Upsilon(2S), and Upsilon(3S) resonances with better than 2% precision by integrating the cross section of e(+)e(-)->Upsilon over the e(+)e(-) center-of-mass energy. Using e(+)e(-) energy scans of the Upsilon resonances at the Cornell Electron Storage Ring and measuring Upsilon production with the CLEO detector, we find dielectron widths of 1.252 +/- 0.004(sigma(stat))+/- 0.019(sigma(syst)) keV, 0.581 +/- 0.004 +/- 0.009 keV, and 0.413 +/- 0.004 +/- 0.006 keV for the Upsilon(1S), Upsilon(2S), and Upsilon(3S), respectively
Constraints on cosmic neutrino fluxes from the Antarctic Impulsive Transient Antenna experiment
No full textWe report new limits on cosmic neutrino fluxes from the test flight of the Antarctic Impulsive Transient Antenna (ANITA) experiment, which completed an 18.4 day flight of a prototype long-duration balloon payload, called ANITA-lite, in early 2004. We search for impulsive events that could be associated with ultrahigh energy neutrino interactions in the ice and derive limits that constrain several models for ultrahigh energy neutrino fluxes and rule out the long-standing Z-burst model
Search for exclusive multibody Non-D(D)overbar decays at the psi(3770) resonance
No full textUsing data collected at the psi(3770) resonance with the CLEO-c detector at the Cornell e(+)e(-) storage ring, we present searches for 25 charmless decay modes of the psi(3770), mostly multibody final states. No evidence for charmless decays is found
Search for the lepton-flavor-violating leptonic B-0 ->mu(+/-)tau(-/+) and B-0 -> e(+/-)tau(-/+)
No full textWe have searched a sample of 9.6x10(6) B (B) over bar events for the lepton-flavor-violating leptonic B decays, B-0-->mu(+/-)tau(-/+) and B-0-->e(+/-)tau(-/+). The tau lepton was detected through the decay modes tau-->lnu(ν) over bar, where l=e,mu. There is no indication of a signal, and we obtain the 90% confidence level upper limits B(B-0-->mu(+/-)tau(-/+))e(+/-)tau(-/+))<1.3x10(-4)
Photon transitions in Upsilon(2S) and Upsilon(3S) decays
No full textWe have studied the inclusive photon spectra in Y(2S) and Y(3S) decays using a large statistics data sample obtained with the CLEO III detector. We present the most precise measurements of electric dipole (E1) photon transition rates and photon energies for Y(2S)-->gammachi(bJ)(1P) and Y(3S)-->gammachi(bJ)(2P) (J=0, 1, 2). We measure the rate for a rare E1 transition Y(3S)-->gammachi(b0)(1P) for the first time. We also set upper limits on the rates for the hindered magnetic dipole (M1) transitions to the eta(b)(1S) and eta(b)(2S) states
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