Accurate theoretical IR and Raman spectrum of Al2O2 and Al2O3 molecules

Abstract

The accurate harmonic vibration frequencies together with the infrared (IR) and Raman intensities of the most stable conformers of Al 2 O 2 and Al 2 O 3 molecules have been calculated by the density functional theory (DFT) method with B3LYP exchange-correlation potential and using a set of the augmented correlated consistent basis sets up to quintuple order. The anharmonic vibration frequencies of the non-linear Al 2 O 2 molecule have also been calculated. The obtained equilibrium geometrical parameters, harmonic and anharmonic vibration frequencies along with the IR and Raman intensities good converge to their limits with increasing the size of the used basis set. A comparison of the calculated harmonic and anharmonic vibrational frequencies with the available experimental ones points out that the small differences between the calculated harmonic and experimental frequencies can be further substantially reduced when calculations of the anharmonic vibrational frequencies will be available for all types of molecular geometries.

Neutral and Multicharged Ions of Small Aluminum Oxides: Structures, Spectroscopy, and Energetics

“…This is in line with the most recent findings, which showed that the inclusion of electron correlation favors the square over the linear. 42,46,54 At ∼3 eV above Square-Al 2 O 2 (X 1 A g ), we locate the non planar Rhombic-Al 2 O 2 (X 1 A 1 ). The newly characterized C 2v structure and the weakly bound AlOOAl and OAlAlO isomers lie higher in energy (at ∼5 eV).…”

“…The vibrational signature of larger aluminum oxide clusters has been obtained by Infrared Resonance Enhanced Multiphoton Ionization spectroscopy (IR-REMPI) by van Heijnsbergen et al, illustrating the effect of the size of the cluster on the spectra. In addition, theoretical calculations, which provided structural and some spectroscopic data, have been performed on different aluminum oxide molecules and small clusters: AlO, , Al 2 O, − AlO 2 , − Al 2 O 2 , ,, Al 2 O 3 , Al 3 O, Al 4 O, Al n O ( n ≤ 10), Al n O 2 , Al 2 O n ( n = 1–4), and Al x O y ( x = 1–4, y = 1–4). , …”

The Limits of the Post‐Growth Optimization of AlN Thin Films Grown on Si(111) via Magnetron Sputtering

“…The intensity of these peaks is tripled for the sample annealed at 1200 °C, whereas the ones found in the craters are less pronounced. The latter can be assigned to the various Al x O y species formed due to the high‐temperature oxidation of AlN. The two bands at 1370 and 1400 cm −1 , which are found for the sample annealed at the highest temperature, indicate AlC 2 and Al 2 H 6 species, respectively.…”

Interplay of thermochemistry and Structural Chemistry, the Journal (volume 22, 2011, issues 1–3) and the discipline

“…Mitin [115] used DFT to show that the most stable conformers of gas-phase Al 2 O 2 and of Al 2 O 3 have similar energy and stability. Small differences between calculated and earlier reported experimentally determined harmonic frequencies have been observed which can be eventually reduced by calculating anharmonic vibrational frequencies for all types of molecular geometries.…”