화학공학소재연구정보센터
Journal of Chemical Physics, Vol.109, No.15, 6312-6319, 1998
Experimental measurement of the transition moment for the (2,0) band of the CN A(2)Pi <- X-2 Sigma(+) red system at 789.5 nm
The square of the electronic-vibrational transition moment for the (2,0) band of the cyano radical (CN) A (2)Pi<--X(2)Sigma(+), red system at 789.5 nm has been determined using a direct time-resolved absorption technique. The line strength of the R-1(8.5) transition of (CN)-C-12-N-14 was measured by comparison to the known line strength of the (HCN)-C-12-N-14(001)<--(000) P(8) infrared v(3) fundamental transition near 3.05 mu m. The CN radical was created by pulsed-laser photolysis of cyanogen, (CN)(2), in a mixture of H-2 and (CN)(2) in either Ar or He carrier gas at 293 K. Both CN and HCN were monitored by time-resolved absorption spectroscopy during the same photolysis laser pulse. A simple kinetic model was used to relate the two absorption features to each other. The square of the electronic-vibrational transition moment for the A<--X(2,0) band was found to be 7.8+/-1.0 x 10(-38) esu(2) cm(2) in good agreement with theoretical calculations based on ab initio quantum chemistry methods.