Laboratory study of the formation of fullerene(from smaller to larger, C44 to C70)/anthracene cluster cations in the gas phase

The formation and evolution mechanism of fullerenes in the planetary nebula or in the interstellar medium are still not understood.Here,we present the study on the cluster formation and the relative reactivity of fullerene cations(from smaller to larger,C44 to C70) with anthracene molecule(C14H10).The experiment is performed in an apparatus that combines a quadrupole ion trap with a time-of-flight mass spectrometer.By using a 355 nm laser beam to irradiate the trapped fullerenes cations(C60+or C70+),smaller fullerene cations C(60-2 n)+, n=1-8 or C(70-2 m)+,m=1-11 are generated,respectively.Then reacting with anthracene molecules,series of fullerene/anthracene cluster cations are newly formed(e.g.,(C14H10)C(60-2 n)+,n=1-8 and(C14H10)C(70-2 m)+,m=1-11),and slight difference of the reactivity within the smaller fullerene cations are observed.Nevertheless,smaller fullerenes show obviously higher reactivity when comparing to fullerene C60+ and C70+.A successive loss of C2 fragments mechanism is suggested to account for the formation of smaller fullerene cations,which then undergo addition reaction with anthracene molecules to form the fullerene-anthracene cluster cations.It is found that the higher laser energy and longer irradiation time are key factors that affect the formation of smaller fullerene cations.This may indicate that in the strong radiation field environment(such as photon-dominated regions) in space,fullerenes are expected to follow the top-down evolution route,and then form small grain dust(e.g.,clusters) through collision reaction with co-existing molecules,here,smaller PAHs.

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 X4AT/2 state of CoS, was identified and assigned to be [24.0014AT/2-X4A7/2. The new observed 4A state most probably originates from the core[10a2][47r3][lla2][153][57r3] 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 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]-X3∑o transitions have been tentatively grouped into five vibrational progressions. Furthermore, dispersed fluorescence and lifetimes of the strong bands have also been measured.

Reinvestigate the C^2Π-X^2Π(0,0)Band of AgO

The C^2Π-X^2Π(0,0)band of AgO has been reinvestigated by laser induced fluorescence spectroscopy with a spectral resolution of ~0.02 cm^−1.The AgO molecules are produced by discharging a gas mixture of O2/Ar with silver needle electrodes in a supersonic jet expansion.By employing a home-made narrowband single longitude mode optical parametric oscillator(SLM-OPO)as the laser source,high-resolution spectra of the C^2Π-X^2Π(0,0)band have been recorded for both 107Ag16O and 109Ag16O isotopologues.The spectroscopic constants of the C^2Π state are consequently determined,with the 109Ag16O one being reported for the first time.The nature of the spin-orbit coupling effect in the C^2Π state is proposed to be due to state mixing with the nearby repulsive 4Σ− and 4Π states.