A selected ion flow tube‐laser induced fluorescence instrument for vibrationally state‐specific ion‐molecule reactions

A selected ion flow tube apparatus is coupled with laser induced fluorescence (LIF) detection for the selective monitoring of ion vibrational states and their reactions. Mass selected ions are injected into a flow tube with a venturi inlet using He carrier gas. A 200 Hz dye laser system provides sensitive LIF detection of the injected ions at densities as low as 1×105 cm−3 for N+ 2. The rotational temperatures of the N+ 2 ions are estimated to be ≊300 K using the LIF detection, while the vibrational temperatures can be high and may be varied by the injection potentials. Vibrationally state‐selected ion‐molecule reactions of N+ 2(v=0, 1, and 2) are studied with N2, Ar, and O2 at thermal kinetic energies (E lab