Predicted predissociation linewidths in the Schumann-Runge bands of O2 compared with recent high resolution measurements

The fine-structure predissociation linewidths for the Schumann-Runge bands were evaluated by the model of Julienne and krauss. The parameters were adjusted and modified to account for the fine-structure data for rotational states of vibrational levels v=0-2, 9-12. The standard deviation of the predicted widths was calculated using the fine-structure data. Green's function method was used to obtain the shifts at the band heads. The analysis showed good agreement between the measured widths and widths obtained using the modified parameters.published_or_final_versio

Laser spectroscopy of NiBr: New electronic states and hyperfine structure

Laser induced fluorescence spectrum of NiBr in the visible region between 604 and 666 nm has been recorded and analyzed. Fourteen bands belonging to three electronic transition systems, namely, [15.1] Δ 52 2 -X Π 32 2, [15.1] Π 32 2 -X Π 32 2, and [14.0] Δ 52 2 -X Π 32 2 have been observed. Spectra of isotopic molecules were also observed and analyzed. Detailed analysis of the recorded spectra indicated that the two electronic states [15.1] Π 32 2 and [15.1] Δ 52 2 lie about 1 cm-1 apart from each other and J -dependent perturbation due to spin-uncoupling interaction has been observed. Least squares fitting procedures involving deperturbation matrix elements were used to fit the observed line positions, which yielded accurate molecular constants for the [15.1] Π 32 2 and [15.1] Δ 52 2 states. In addition, the (1,0) band of the [15.1] Δ 52 2 -X Π 32 2 transition shows partially resolved hyperfine structure that was caused by the interaction of unpaired electron with the magnetic moment of the Br nucleus (nuclear spin of I=32) in the excited state. The rapid decrease in hyperfine width as J increases suggests that the hyperfine coupling in the excited state conforms to Hund's case (aΒ) coupling scheme. © 2006 American Institute of Physics.published_or_final_versio

Improvements in the mechanical structure of the linear switched reluctance motor

Author name used in this publication: Norbert C. CheungRefereed conference paper2007-2008 > Academic research: refereed > Refereed conference paperVersion of RecordPublishe

Electronic transitions of cobalt monoboride

Electronic transition spectrum of cobalt monoboride (CoB) in the visible region between 495 and 560 nm has been observed and analyzed using laser-induced fluorescence spectroscopy. CoB molecule was produced by the reaction of laser-ablated cobalt atom and diborane (B 2H 6) seeded in argon. Fifteen vibrational bands with resolved rotational structure have been recorded, which included transitions of both Co 10B and Co 11B isotopic species. Our analysis showed that the observed transition bands are ΔΩ=0 transitions with Ω″ = 2 and Ω″ = 3 lower states. Four transition systems have been assigned, namely, the [18.1] 3Π 2-X 3Δ 2, the [18.3]φ 3φ 3-X 3Δ 3, the [18.6]3-X 3Δ 3, and the [19.0]2-X 3Δ 2 systems. The bond length, r o, of the X 3Δ 3 state of CoB is determined to be 1.705 Å. The observed rotational lines showed unresolved hyperfine structure arising from the nuclei, which conforms to the Hunds case (a β) coupling scheme. This work represents the first experimental investigation of the CoB spectrum. © 2011 American Institute of Physics.published_or_final_versio

Rotational and hyperfine analysis of the near infrared 3Φ4-X3Φ4 transitions of CoCl and Col

A rotational and hyperfine analysis of the 3φ 4- 3φ 4 transition of CoCl and CoI in the near infrared region was reported. Six and eight vibronic transition band soft CoCl and CoI, respectively, were recorded and analyzed. Accurate molecular parameters for both the upper and the ground 3φ 4 states were determined by least squares fitting of line positions of observed bands simultaneously for each molecule, which yielded accurate molecular parameters for both the upper and lower 3φ 4 states.published_or_final_versio

Theoretical studies of the first-row transition metal phosphides

B3LYP calculations were performed with an extended basis set on the first-row TM phosphides. It was found that the ground states of these phosphides follow those of the isoelectronic sulfides. In addition, the covalent character of these phosphides increase across the series from Sc to Cu, in accordance with the electronegativity difference.published_or_final_versio

Near-infrared laser spectroscopy of Nil

Laser-induced fluorescence spectrum of Nil in the near infrared region of 714-770 nm has been recorded. Seven bands belonging to three electronic transition systems were observed and analyzed: the (0,0), (1,0), and (2,0) bands of [13.3] 2∑ + -A 2∏ 3/2 system; the (1,1) and (0,1) bands of [13.9] 2∏ 3/2-X 2Δ 5/2 system; and the (0,0) and (1,0) bands of [13.9] 2∏ 3/2-A 2∏ 3/2 system. Spectra of isotopic molecules confirmed the vibrational quantum number assignment of the observed bands. Least-squares fit of rotationally resolved transition lines yielded accurate molecular constants for the v = 0-2 levels of the [13.3] 2∑ + state, the v = 0 level of the A 2∏ 3/2, and the v = 1 level of the X 2Δ 5/2 state. The vibrational separation, ΔG 1/2, of the ground state was measured to be 276.674 cm -1. With the observation of the [13.9] 2∏ 3/2-A 2∏ 3/2 and [13.9] 2∏ 3/2-X 2Δ 5/2 transitions, we accurately determined the energy separation between the A 2∏ 3/2 and the X 2Δ 5/2 to be 163.847 cm -1. This confirms that the order of the A 2∏ 3/2 and X 2Δ 5/2 states in Nil is reversed when compared with other nickel monohalides. © 2004 American Institute of Physics.published_or_final_versio

Laser spectroscopy of NiBr: Ground and low-lying electronic states

Rotationally resolved near-infrared spectroscopic study of electronic transition of low-lying states of NiBr was reported using the technique of laser vaporization/reaction with supersonic cooling and laser induced fluorescence (LIF) spectroscopy. The reaction of laser ablated nickel atoms and ethyl bromide produced NiBr molecules. Least squares fit of rotationally resolved transition lines yielded accurate molecular constants.published_or_final_versio

Electronic Transitions of Palladium Dimer

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Comment on predissociation of O2 in the B state

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