J. Kalcher et Af. Sax, ELECTRON-AFFINITIES AND SINGLET-TRIPLET (DOUBLE-QUARTET) SPLITTINGS OF SMALL UNSATURATED SILICON HYDRIDE SYSTEMS, Journal of molecular structure. Theochem, 119(1), 1994, pp. 41-46
The singlet-triplet (Delta E(ST)) and doublet-quartet (Delta E(DQ)) sp
littings and electron affinities (EA) of various silicon hydrides and
substituted species were calculated. Electropositive substituents (Li
and SiH3) favour the high-spin states, others (CH3 and F) the low-spin
states. EA values are increased by silyl and decreased by methyl subs
tituents. The Delta E(DQ) values are -0.57, 0.92, 1.68 and 3.63 eV for
SiLi, SiSiH3, SiCH3 and SiF, respectively. The corresponding EA value
s are 0.88, 1.32, 0.65 and 0.76 eV, respectively. CH2-SiH3, SiH2-CH3 a
nd SiH2-SiH3 have EAs of 0.39, 0.79 and 1.46 eV. Si2H is found to have
several minima on the doublet and quartet energy surfaces. The smalle
st Delta E(DQ) is 1.1 eV, similar to the value of 1.35 eV of Si2H3. Bo
th species have electron affinities > 2 eV. The disilene anion (Si2H4-
) was considered, particularly with regard to its stability to rotatio
nal isomerization.