Acta Phys. -Chim. Sin. ›› 2000, Vol. 16 ›› Issue (06): 491-495.doi: 10.3866/PKU.WHXB20000603

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Hel Photoelectron Spectroscopic Study on the Electronic Structure of the Derivatives of 1,2,5-thiadiazole

Cao Xiao-Yan, Wu Wei, Wang Dong, Ge Mao-Fa, Wang Dian-Xun   

  1. State Key Laboratory for Structural Chemistry of Unstable and Stable Species,Institute of Chemistry,Chinese Academy of Sciences,Beijing 100080
  • Received:1999-09-22 Revised:1999-12-27 Published:2000-06-15
  • Contact: Wang Dian-Xun


The HeI photoelectron spectra (UPS) of 3-chloro-1,2,5-thiadiazole (A)and 3,4-dichloro-1,2,5-thiadiazole (B) are reported for the first time. The assignment of the UPS bands for the compounds studied has been made by the band shapes, the relative intensity of the bands and the experimetal ionization energies as well as ab initio Gaussian 94 STO 6G calculations on the molecules studied. The lower ionization energy of B compound compared with that of A might be due to the “crowding effect”of two chlorine atoms in the B molecule. The total energy (Etot=-1501.1 a.u.) for B compound is lower than that (Etot=-1042.2 a.u.) of A compound. This means also that B has higher thermal pyrolysis energy which is consistence with the result of the interstellar species produced by pyrolysis of A and B.

Key words: Hel photoelectron spectra(UPS), Derivatives 1,2,5-thiadiazole, Ab initio