The generation and trapping of 28SiH+2 and 29SiH+2 in neon matrices at 4 K: Electron spin resonance and theoretical investigations
Knight, L. B.; Winiski, M.; Kudelko, P.; Arrington, C. A. The generation and trapping of 28SiH+2 and 29SiH+2 in neon matrices at 4 K: Electron spin resonance and theoretical investigations. J. Chem. Phys. 1989, 91, 3368-3368.
The 2 8SiH+ 2 2 9SiH+ 2 cation radicals have been generated under neon matrix deposition conditions at 4 K by the photoionization (16.8 eV) of SiH4(g). A resolution of the 2 9Si and hydrogen Atensors was possible which enables a complete characterization of the unpaired electron in this highly reactive ionic species for its Xâ€‰ 2 A 1ground electronic state. The Atensor assignments were facilitated by the occurrence of preferential orientation of the isolated SiH+ 2 molecule in the neon lattice. A b i n i t i otheoretical calculations of the nuclear hyperfinetensors were conducted which showed good agreement with the experimental results. The experimental magnetic parameters in neon at 4 K are: g x =2.0043(3), g y =1.9970(3), g z =2.0018(3); A x (H) =110.4(3), A y (H)=124.1(3), A z (H)=116.6(3); for 2 9Si, A x =âˆ’762.9(3), A y =âˆ’760.8(3) and A z =âˆ’1005.0(3) MHz where X is perpendicular to the molecular plane and Z lies along the C 2 axis of the C 2v radical. No experimental evidence for SiH+ 4 or the complex, SiH+ 2 â‹…â‹…â‹…H2 was obtained. Theoretical calculations indicate that hyperfine structure from the â€˜â€˜complexedâ€™â€™ H2 should be resolvable if this species was present. However, rotational averaging of H2 above the SiH+ 2 plane would reduce the hfi of H2 and might prevent its detection.
Journal of Chemical Physics