No abstract

The influence of collisional transfers and perturbations on measured A and B state lifetimes in CN.

Time-resolved spectra and intensities of the different vibrational bands from the B3Πg-A3Σ+u of N2 have been measured as a function of pressure using the High Frequency Deflection technique. Both the pressure of nitrogen and added catalyst gases (He, Ne and Ar) were varied from 0.6 to 20 m torr. In the case of v' = 6, 7, 11 and 12 strong pressure effects were noted both for the apparent lengthening of lifetimes and increase in intensities. Little or no pressure effects were seen for v' = 2, 3, 4, 5, 8, 9 and 10. These results have been explained in terms of resonance collisional transfer in which a metastable state is transferred through collison to the B state. The total collisional transfer rate coefficient to the B state was determined to be approximately 10-10 cm3 s-1, molecule. Data on the lifetimes extrapolated to zero pressure were used to derive the oscillator strength: f00abs = 1.69 ± 0.15 × 10-3.

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The proton transfer reactions from ArH+ to H2, D2, CH4, N2, O2, CO, CO2, and the corresponding deuteron transfer reaction of ArD+ with H2 and D2 have been investigated in a drift tube with mass selected ion injection. The use of helium and argon buffer gases permits a qualitative assessment of vibrational energy effects along with a quantitative assessment of the influence of translational energy on reaction rates. These exothermic reactions all proceed with large rate coefficients which approach the collision rates for the respective reactants. All except the reaction of ArH+ with H2 (D2) were independent of translational energy over the range investigated. In an argon buffer equilibrium is readily established for the reaction ArH++H2⇄H3++Ar. A treatment of the center-of-mass kinetic energy as a ’’translational temperature’’ permits the construction of a van’t Hoff plot for this reaction from which a value of Δ(PA)=0.55 eV is obtained, which is consistent with the accepted proton affinities of H2 and Ar.