Acta Phys. -Chim. Sin. ›› 2010, Vol. 26 ›› Issue (10): 2787-2792.doi: 10.3866/PKU.WHXB20100914


Photodissociation Mechanism of Cyanogen Azide

CI Cheng-Gang, DUAN Xue-Mei, LIU Jing-Yao, SUN Chia-Chung   

  1. State Key Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry,Jilin University, Changchun 130023, P. R. China
  • Received:2010-05-04 Revised:2010-06-02 Published:2010-09-27
  • Contact: LIU Jing-Yao
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (20333050, 20303007, 20973077) and Program for New Century Excellent Talents in University, China (NCET).


We investigated the photodissociation mechanism of cyanogen azide (N3CN) at the MRCI+Q//CAS(10,9)/6-311+G(2df) level of theory using the multi-reference state method. The optimized structures and energies of the minima, transition states, singlet/singlet conical intersection and singlet/triplet crossing points of the ground and low-lying excited states were obtained to explore the potential energy surfaces of N3CN. The vertical excited energies calculated at the MRCI+Q//CAS(10, 9) level were compared with the experimental data. It is shown that N—N bond fission to form N2+NCN is the predominant dissociation pathway on the S0, S1, S2, and T1 surfaces whereas the C—N bond fission channel is the minor pathway. The 220 nm absorption peak observed experimentally corresponds to an excitation from the S0 to the S1 state leading to the major photodissociation product NCN[a1Δg]. The 275 nm absorption peak corresponds to the S0-T1 transition leading to the formed ground-state product NCN[X3Σ-g ] via the barrierlessly direct dissociation in the T1 state. Our theoretical results agree well with experimental observations.

Key words: Reaction mechanism, Cyanogens azide, Photodissociation, Potential energy surface intersectionpoint