The anionic products from the reactions between metal（M=Ag, Au, Pd, Pt, Pb and Bi） vapour produced by laser ablation and hexafluorobenzene seeded in carrier gas（Ar） were studied by means of a homemade reflectron time-of-flight mass spectrometry（RTOF-MS）. Experimental results show that the dominant products were [MmC6F6]^- complexes for the reactions ofAg, Au, Pd and Pt with C6F6, while the dominant products were [MmC6F5]^- complexes for the reactions of Pb and Bi with C6F6. The formation mechanisms of the products, including the adsorption of metal cluster anions on hexafluorobenzene and the C--F cleavage induced by metal cluster anions, were discussed.
SUN ZhangSUN Shu-taoLIU Hong-taoZHU Qi-heGAO ZhenTANG Zi-chao
The photodissociation dynamics of IC1 has been studied near 304 and 280 nm on a simple miniature time of flight (mini-TOF) photofragment translational spectrometer with a short pulse of a weak acceleration field. An intense hot band effect was ob- served. Many small peaks were resolved in each photofragment translational spectrum (PTS). Based on simulations, the principal peaks were assigned not only to the different photodissociation channels (1) I + C1, (2) I + CI*, (3) I* + C1, or (4) I* + CI*, but also to the different chlorine isotopes (35C1 and 37C1). Moreover, some extra peaks showed the existence of an intense hot band effect from vibrationally excited ICI molecules, though only a few percent of ICI molecules remained in the vibrationally excited states in our supersonic molecular beam. Based on the spectra near 304nm, the quantum yield Φ of each channel, the curve crossing, and the branching fraction a from each transition state were determined.
The photodissociation of ethyl iodide at 279.71, 281.73, 304.02 and 304.67 nm has been studied on our new mini-photofragment translational spectrometer with a total flight path of only 5 cm. Some vibra-tional peaks are firstly resolved in the TOF spectra of I*(2P1/2) and I(2P3/2) channels. These vibrational peaks are assigned to the excitation states (ν2 = 0, 1, 2,…) of the umbrella mode (ν2, 540 cm-1) of the photofragment C2H5, and the distribution of the vibrational states is obtained. The dissociation energy has been determined to be D0(C-I)=2.314 ± 0.03 eV. The energy partitioning of the available energy (Eavl=ET+Eint=ET+EV,R) calculated from our experimental data E int /E avl= 22.1% at 281.73 nm, 22.4% at 304.02 nm for the I* channel, and E int /E avl= 25.2% at 279.71 nm, 25.9% at 304.67 nm for the I channel, seem to be more reliable.
BI WeiBin, XU XiLing, HUANG JianGou, XIAO DaoQing & ZHU QiHe Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, China
The laser-induced fluorescence excitation spectrum of CoC was recorded in the spectral region from 13500 cm^-1 to 22000 cm^-1, in which the CoC molecules were produced by the reaction of sputtered cobalt atoms with methanol under supersonic jet cooled conditions. Much of the visible spectrum was assigned to transitions between the X2∑^＋ ground state and F2∑^＋ state. The 11 bands assigned as （v＇=3-13, 0） transitions of the F^2∑^＋-X^2∑^＋ band system were observed and rotationally analyzed. Equilibrium constants for the F^2∑^＋ state were Te=13628 cm^-1, We=669 cm^-1, ωeХe=4.3 cm^-1, Be=0.546 cm^-1, and Re=1.758A. Some new bands were observed.
