Effects of ZnO nanowire length on surface-assisted laser desorption/ionization of small molecules.

The effects of nanowire (NW) length on surface-assisted laser desorption/ionization (SALDI) mass spectrometry (MS) of small molecules were investigated using ZnO NWs of 50 nm diameter with a broad range of lengths ranging from 25 to 1600 nm. Characterization of the ZnO NWs revealed that the length was the only parameter that varied in this study, while other properties of the NWs remained essentially the same as the bulk properties. Experiments on SALDI efficiency exhibited that the SALDI processes on NWs have a certain length window.

Ultraviolet photodepletion spectroscopy of dibenzo-18-crown-6-ether complexes with alkali metal cations.

Ultraviolet photodepletion spectra of dibenzo-18-crown-6-ether complexes with alkali metal cations (M(+)-DB18C6, M = Cs, Rb, K, Na, and Li) were obtained in the gas phase using electrospray ionization quadrupole ion-trap reflectron time-of-flight mass spectrometry. The spectra exhibited a few distinct absorption bands in the wavenumber region of 35 450-37 800 cm(-1). The lowest-energy band was tentatively assigned to be the origin of the S(0)-S(1) transition, and the second band to a vibronic transition arising from the "benzene breathing" mode in conjunction with symmetric or asymmetric stretching vibration of the bonds between the metal cation and the oxygen atoms in DB18C6.