Properties of Sc3, Y3, and Sc13 molecules at low temperatures, as determined by ESR
Knight, L. B.; Woodward, R. W.; Van Zee, R. J.; Weltner, W. Properties of Sc3, Y3, and Sc13 molecules at low temperatures, as determined by ESR. J. Chem. Phys. 1983, 79, 5820-5820.
Sc 3 and Y 3 molecules have been isolated in rare gas matrices at temperatures near 4 K. ESRspectra establish that the structure of Sc 3 is an equilateral triangle at 4â€“30 K with a 2 Aâ€² 1 ground state. The possibility remains that Sc 3 is a fluxional bent molecule with a very low barrier to pseudorotation. The 45 Sc hyperfine splitting indicates that the unpaired electron has little s character and is delocalized in 3d orbitals on the three equivalent atoms. Y 3 , however, is not equilateral and is most probably a bent molecule at these temperatures with the spin again distributed over the 3d atomic orbitals, but in a 2 B 2 ground state. La 3 was not observed and is therefore judged to be a linear orbitally degenerate molecule. Under special conditions, a cluster of exceptional stability Sc x , where xâ‰¥9 is formed in neon matrices. From its uniqueness and from the hyperfine structure in its ESR spectrum, it is suggested that it may be Sc 13 with an icosahedral structure. This places 12 equivalent atoms at the vertices and one at the center of the icosahedron and leads to a 2 A g ground state. However, Sc x as observed at 4 K could also be a dynamic Jahnâ€“Teller molecule with only a small barrier between its distorted conformations.
Journal of Chemical Physics