A NEW INSTRUMENT FOR MEASURING THE RADIATIVE LIFETIMES AND FOR STUDYING THE STATE-SELECTED BIMOLECULAR REACTION CHEMISTRY OF SMALL IONIC SPECIES

A design for a new Fourier transform-ion cyclotron resonance mass spectrometer (FT-ICR) is presented. The FT-ICR consists of two differentially pumped vacuum chambers, one housing two Newport pulsed valves, the other housing a 2 in cubic ICR cell which employs an IonSoec FTMS 2000 electronics console for detection. The combination of pulsed valves and an excimer-pumped dye laser permits the formation of vibrationally state-selected ions via resonance-enhanced multiphoton ionization in the absence of relaxing collisions. Experiments are presented which demonstrate that the state-selected ions exist at near-thermal translational energies and sub-thermal rotational energies. Data are presented illustrating the capabilities of this instrument for the measurement of long-lived electronic and vibrational state radiative lifetimes, as well as the reactivity of vibrationally state-selected NO+ (X1Σ+, υ = 0, 1, 2, 3) with a number of neutral substrate molecules. © 1990.