CH radicals were prepared by photolysis of CHBr3 molecule,and were ionized by the same laser.Monitoring CH+,C+and H+ions signals,the CH REMPI spectrum was obtained in the range of 241-251nm.The CH D2Π(v=2)A2Δ(v=0)(1+1) resonance transition was assigned.The rotational constants of CH D2Π(v=2) state were obtained by analyzing the REMPI spectrum.It was found that there is a broad feature peak at 247.6nm in C+mass-specific spectrum.Based on the theoretical result,the broad feature peak is correlated with an unreported predissociation Rydberg state (3 2Π) which converges to CH+(A,1Π) state.
