Ab initio determination of the equilibrium geometry and vibrational frequencies of borazine

Journal of Molecular Structure: THEOCHEM Volume 236, Issue 1-2, 1 November 1991, Pages 29-39 Ab initio determination of the equilibrium geometry and vibrational frequencies of borazine (Article) Ramondo, F., Portalone, G., Bencivenni, L. Dipartimento di Chimica, Universitá degli Studi di Roma La Sapienza, P. le A. Moro 5, 00185 RomaItaly View references (20) Abstract The equilibrium structure of borazine, B3N3H6, has been optimized at the HF-SCF level using the 6-31G, 6-31G*, 6-31 + G*, 6-31 + + G**, 6-311G**, DZP and TZP basis sets and at the secondorder Moeller-Plesset perturbation theory, with all orbitals active, with the 6-31G* basis set (MP2/ 6-31G*). The D3h symmetry conformation is established to be, at all the adopted levels of theory, the global minimum of the molecule. The planar structure has been studied employing several basis sets and the effects of basis set extension and of polarization d-functions on the molecular geometry are discussed. The bond distances and the ring angles of borazine determined at the MP2/6-31G* level are, (BN) 1.430 Å, (BH) 1.197 Å, (NH) 1.012 Å, (BNB) 122.9° and (NBN) 117.1°. HF-SCF and MP2/6-31G* vibrational frequencies have been calculated in the harmonic approximation and the vibrational spectrum of borazine is reassigned accordingly. © 199