Photodissociation spectra of the complexes Mg^＋-NCSCH₃ in the spectral region of 230～440 nm and Ca^＋-NCSCH₃ in 320～560 nm were studied. Mass spectra of the products of photo-induced reaction of the complexes Mg^＋-NCSCH₃ and Ca^＋-NCSCH₃ exhibits the presence of Mg^＋(Ca^＋) from nonreaction quenching, Mg^＋(Ca^＋)NC and Mg(Ca^＋)^＋NCS from the rupture of S-C bonds, and rearrangement products Mg^＋(Ca^＋)-CHSH. The photodissociation spectra consist of two broad peaks for Mg^＋-NCSCH₃, and three broad peaks for Ca^＋-NCSCH₃ on the red and blue sides of atomic transition (3²S→3²P for Mg^＋; 4²S→4²P for Ca^＋). The calculated absorption spectrum corresponding to the minimum-energy structure agrees well with the experimental spectrum for Mg^＋-NCSCH₃, but poorly for Ca^＋-NCSCH₃. The reasons are that CIS method neglected correlation effects and orbital mixing occured between 3d and 4s during Ca^＋-based transition.

Key words: metal cation-molecule complex, laser photodissociation, time-flight mass spectrum