Cheng-bing Qin

Optical amplification of Eu(TTA) 3 Phensolution-filled hollow optical fiber

A liquid core optical fiber (LCOF) composed of hollow fiber and a solution of Eu(TTA)(3)Phen (TTA=2-thenoyltrifluoroacetone, Phen=1, 10-phenanthroline) in dimethyl sulfoxide (DMSO) has been fabricated, in which the concentration of Eu(TTA)(3)Phen in DMSO is 0.8 wt.%, the core diameter of the LCOF is 10 μm, and the fiber length is 8.1 cm. By the end pumping with a diode-pumped solid-state laser at 355 nm, a small optical signal at 613 nm was amplified with a gain of 8.2 dB at a pump power of 203 mW. Based on this experimental result, a liquid core optical fiber amplifier can be realized by the LCOF, which has wide potential applications in many optical devices.

Time-sliced Velocity Map Imaging Study on Photodissociation of Neopentyl Bromide and Tert-pentyl Bromide at 234 nm

We present a first velocity map imaging study on the 234 nm photodissociation dynamics of two carbon-chain branched alkyl bromides, neopentyl bromide (denoted as NPB) and tert-pentyl bromide (denoted as TPB). Unlike the 234 nm photodissociation of the unbranched n-C5H11Br molecule where only a direct fission of the C—Br bond is involved, the branched NPB and TPB molecules exhibit one and two more independent dissociation pathways with much energy being decayed via an extensive excitation of the bending modes of the parent molecules prior to the C—Br bond fission. This observation strongly suggests that the dissociation coordinate for the two carbon-chain branched molecules is no longer solely ascribed to the C—Br stretching mode but rather a combination of the bending-stretching modes.

Laser‐induced Fluorescence Spectroscopy of CoS: Identification of a New Excited State Arising from the Ground State

Laser‐induced fluorescence excitation spectra and dispersed fluorescence spectra of cobalt sulfide (CoS) have been recorded in the energy range of 22400–24400 cm−1 (corresponding to 446–409 nm). A new electronic transition progression with six vibronic bands, stemming from the X4Δ7/2 state of CoS, was identified and assigned to be [24.00]4Δ7/2−X4Δ7/2. The new observed 4Δ state most probably originates from the core[10σ2][4π3][11σ2][1δ3][5π3] electronic configuration. Strong perturbations are found to extensively exist in the transition bands of this new state. The rotational constants and lifetimes of these bands have been determined.

Laser-induced Fluorescence Spectroscopy of NiCl in 12900-15000 cm-1

Laser-induced fluorescence excitation spectra of jet-cooled NiCl molecules were recorded in the energy range of 12900–15000 cm−1. Six vibronic bands with rotational structure have been observed and assigned to the [13.0]2Π3/2(ν′= 0–5)-X2Π3/2(ν″=0) transition progression. The relevant rotational constants, significant isotopic shifts, and (equilibrium) molecular parameters have been determined. In addition, the lifetimes of the observed bands have also been measured.

Laser-induced Fluorescence and Dispersed Fluorescence Spectroscopy of NiB: Identification of a New 2Π State in 19000–22100 cm−1

The laser-induced fluorescence excitation spectra of jet-cooled NiB radicals have been recorded in the energy range of 19000–22100 cm−1. Eleven bands have been assigned to the [20.77]2Π-X2Σ+ transition system for the first time. The dispersed fluorescence spectra related to most of these bands have been investigated. Vibrationally excited levels of the ground electronic state, with v″ up to 6, have been observed. In addition, the lifetimes for almost all the observed bands have also been measured.

Laser-induced Fluorescence Spectrum of CoS Between 15200 and 19000 cm?1

Laser-induced fluorescence excitation spectra of jet-cooled CoS molecules have been recorded in the energy range of 15200–19000 cm−1. Five transition progressions have been reported for the first time, the assignments of these progressions have been derived from a rotational analysis of vibronic bands and they are determined to be [15.58]4Δ7/2-X4Δ7/2, [16.02]4Δ7/2-X4Δ7/2, [16.50]4Δ7/2-X4Δ7/2, [17.80]4Π5/2-X4Δ7/2, and [18.00]4Δ7/2-X4Δ7/2 transitions. In addition, under the supersonic jet condition the fluorescent lifetimes of these vibronic states were measured by exponentially fitting the fluorescence decay. Based on the observed spectra and the measured lifetimes of the vibronic states, the newly identified electronic states are discussed.

Laser-induced Fluorescence Excitation Spectrum of NiS in 1550017200 cm1

The laser-induced fluorescence excitation spectrum of jet-cooled NiS molecule has been recorded in the energy range of 1550017200 cm1. Fifteen bands have been assigned as three transition progressions: [15.65]31(v = 04)-X30(v = 0), [15.69]30(v = 04)-X30(v = 0), and [15.81]31(v = 04)-X30(v = 0). Spectroscopic constants for the three newly identified electronically excited states have been determined for the first time. In addition, the lifetimes for most observed vibronic bands have also been measured.

Laser‐induced Fluorescence Spectroscopy of NiS: Identification of a Low‐lying Electronic State

Laser‐induced fluorescence excitation spectra of jet‐cooled NiS molecules were recorded in the energy range of 12200–13550 cm−1. Four vibronic bands with rotational structure have been observed and assigned to the [12.4]3∑0−‐X3∑0− transition progression. The relevant rotational constants, significant isotopic shifts, and (equilibrium) molecular parameters have been determined. In addition, the lifetimes of the observed bands have also been measured.

Laser‐induced Fluorescence Spectroscopy of NiO between 510 and 650 nm

Laser‐induced fluorescence excitation spectra of NiO have been recorded in the wavelength region of 510–650 nm under supersonic molecular beam conditions. More than fifty bands have been observed and rotationally analyzed to determine the molecular constants. The excited states exhibit highly irregular variations in terms of isotopic shifts, vibrational intervals, and rotational constants. Twenty‐six bands attributed to [Ω=0, 1]−X3Σ0− transitions have been tentatively grouped into five vibrational progressions. Furthermore, dispersed fluorescence and lifetimes of the strong bands have also been measured.

Cavity Ringdown Spectroscopy of PH2 Radical in 465–555 nm

Absorption spectra of jet-cooled PH2 radicals were recorded in the wavelength range of 465–555 nm using cavity ringdown spectroscopy. The PH2 radicals were produced in a supersonic jet by pulsed direct current discharge of a mixture of PH3 and SF6 in argon. Seven vibronic bands with fine rotational structures have been observed and assigned as 000, 2n0, and 2n1 (n = 1–3) bands of the A2A1−X2B1 electronic transition. Rotational assignments and rotational term values for each band were re-identified, and the molecular parameters including rotational constants, centrifugal distortion constants, and spin-rotation interaction constants were also improved with reasonably high precision. In addition, large perturbations observed in each quantum number of total angular momentum of the a axis level of the excited vibronic states were briefly discussed.