Investigation of the vibrational spectra of carbaphosphaboranes and carbaarsaboranes

The electronic structure of 1,2-PCB10H11 molecular films: a precursor to a novel semiconductor

“…These differences (as summarized in Table 2) could be due to a response from the solution (increasing the dipole response in IR), or cage screening in the solid state (decreasing the dipole response for the condensed molecu lar fi lm). The latter explanation, invoking a response of the molecular solid to some vibrational modes, is also suggested by the fact that we do observe some modes in our infra red absorption spectra that are not observed in solution (al though they are observed in the solution Raman spectrum of 1,2-PCB 10 H 11 [57]) when the dipole change involved is large.…”

“…Some of these modes are observed for 1,2-PCB 10 H 11 in solution by Raman spectroscopy [57], as summarized in Table 2. The IR absorption loss observed at 735 cm −1 contains both B-H modes that are coupled to a skeletal mode as well as C-B and P-C stretching modes, as indicated in Table 2, thus explain the somewhat greater width of this feature.…”

“…The observed loss is in generally good agreement with our calculated values. Many of these modes that are not observed in the molecular solid are observed in so lution, particularly if coupled to a wagging or bending B-H mode [57]. These differences (as summarized in Table 2) could be due to a response from the solution (increasing the dipole response in IR), or cage screening in the solid state (decreasing the dipole response for the condensed molecu lar fi lm).…”

“…The vibrational modes are roughly identifi ed by υ s,a for symmetry or antisymmetric stretching modes, δ for bending modes, w for wagging modes, r for rocking modes, and t for twisting modes but because of the low point group symmetry and the coupling to skeletal modes, the assignments are sometimes ambiguous. {*} indicates this work and { †} refers to reference [57].…”

The Influence of the Molecular Dipole on the Electronic Structure of Isomeric Icosahedral Dicarbadodecaborane and Phosphacarbadodecaborane Molecular Films

“…The comparison of the theoretical [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] and experimental [25][26][27][28][29][30] electronic structure, as well as the vibrational modes [31][32][33][34] for the various isomers of the closo-carboranes has a rich history. For the isolated molecules, the trends expected from theory seem to be born out in experiment with only slight differences observed between the various carboranes, although closo-1,12dicarbadodecaborane (paracarborane) does have a somewhat greater stability and symmetry than the other icosahedral isomers of closo-C 2 B 10 H 12 .…”