The electronic states of the diborane ion determined by photoelectron spectroscopy

Ab Initio and Electron Propagator Theory Study of Boron Hydrides

“…The PES experiments have been conducted for boron hydrides such as diborane, tetraborane(10), pentaborane(9), , decaborane(14), , and other higher boranes 18,19 (where the numbers in parentheses represent the number of H atoms). Ab initio work was also performed correspondingly to make the assignments to the spectra. 15b,− However, there are several factors to be considered in the selection of the level of theory and basis sets. Much computational work on the electron-deficient boranes has shown that electron correlation methods are essential to predict energies and geometries that are in good agreement with the experimental data.…”

UV Photoelectron Spectra of the μ-Hydrido Bridge-Bonded Molecules B2H6, GaBH6, and Ga2H6

“…Ab initio and density functional calculations have predicted a D 2 h minimum energy structure for the molecule and vibrational properties in good agreement with the observed infrared and Raman spectra. − Similar calculations give grounds for believing that the aluminum analogue Al 2 H 6 is more stable than Ga 2 H 6 with respect to its elements, but Al 2 H 6 has yet to be authenticated in practice by anything more compelling than a molecular ion peak in the mass spectrum of the vapors formed when aluminum is evaporated into a hydrogen atmosphere − ,− and experimental − investigations of this molecule stretching back over 50 years. The “intermediate” molecule gallaborane, GaBH 6 , has been identified by its vibrational spectra 24 and electron-diffraction pattern 35 as having the structure H 2 Ga(μ-H) 2 BH 2 , again with properties close to those anticipated by theoretical studies. , …”

“…This work reports a He I photoelectron spectroscopic study of these molecules designed to probe their electronic structure and bonding. Diborane has previously been the subject of extensive studies by photoelectron spectroscopy (PES); − it is of much interest therefore to compare the photoelectron spectrum of diborane with those displayed by digallane and gallaborane.…”

“…[6][7][8][9][10][11][12][13] Similar calculations give grounds for believing that the aluminum analogue Al 2 H 6 is more stable than Ga 2 H 6 with respect to its elements, but Al 2 H 6 has yet to be authenticated in practice by anything more compelling than a molecular ion peak in the mass spectrum of the vapors formed when aluminum is evaporated into a hydrogen atmosphere. 14 By contrast, the familiar diborane molecule, B 2 H 6 , is well-known to possess a bridged, dimeric D 2h structure on the evidence of extensive computational [8][9][10][11][12][13][15][16][17][18][19] and experimental [20][21][22][23][24][25][26][27][28][29][30][31][32][33] investigations of this molecule stretching back over 50 years. The "intermediate" molecule gallaborane, GaBH 6 , has been identified by its vibrational spectra 24 and electron-diffraction pattern 35 as having the structure H 2 Ga(µ-H) 2 BH 2 , again with properties close to those anticipated by theoretical studies.…”

“…14 By contrast, the familiar diborane molecule, B 2 H 6 , is well-known to possess a bridged, dimeric D 2h structure on the evidence of extensive computational [8][9][10][11][12][13][15][16][17][18][19] and experimental [20][21][22][23][24][25][26][27][28][29][30][31][32][33] investigations of this molecule stretching back over 50 years. The "intermediate" molecule gallaborane, GaBH 6 , has been identified by its vibrational spectra 24 and electron-diffraction pattern 35 as having the structure H 2 Ga(µ-H) 2 BH 2 , again with properties close to those anticipated by theoretical studies. 36,37 Additional spectroscopic investigations on digallane and gallaborane are desirable for characterizing more fully these µ-hydrido bridge-bonded species.…”