Measurement of an Emission Cross Section for the Collision ReactionH++N2(X1Σg+,v=0)→H(3p,3d)+N2+(B2Σu+,v=0)Using Photon-Coincidence Techniques

The measurement of the cross section for the emission of a Balmer-$\alpha$ and a $\mathrm{N}_2^{}{}_{}{}^{+}$(0, 0) first-negative-band photon from a hydrogen atom and a $\mathrm{N}_2^{}{}_{}{}^{+}$ molecule excited simultaneously in the same ${\mathrm{H}}^{+}$ + ${\mathrm{N}}_2$ electron-capture collision has been performed in the proton velocity range from 0.54 × ${10}^8$ cm/sec to 2.40 × ${10}^8$ cm/sec. The measurement has been accomplished using the technique of single photon-coincidence detection. To within the random error of the experiment, the cross section has only a single-peak structure with a maximum value of 1.2 × ${10}^{-18\mathrm{}}$ ${\mathrm{cm}}^2$ at a velocity of 1.15 × ${10}^8$ cm/sec. The magnitude and shape of the measured cross section is found to be in good agreement with a cross section calculated by assuming that final-state excitations of the two product systems are uncorrelated.