Sambrano, Julio Ricardo [UNESP]Souza, Aguinaldo Robinson de [UNESP]Queralt, Joaquim JosepAndrés, JuanLongo, Elson [UNESP]2014-05-202014-05-201999-07-01Química Nova. Sociedade Brasileira de Química, v. 22, n. 4, p. 501-505, 1999.0100-4042http://hdl.handle.net/11449/27562Ab initio Hartree-Fock (HF), Density Functional (B3LYP) and electron correlation (MP2) methods have been used to caracterize the aqueous medium intramolecular hydrogen bond in a-alanine. The 6-31G* and 6-31++G** were taken from Gaussian94 library. We were concerned on the structure of three conformers of a-alanine, in their neutral form plus on the structure of the zwitterionic form (Z). The Z structure is a stationary point at the HF/6-31G* level but it is not when diffuse functions and electron correlation are included. This results shows that the Z form does not exist in the gas phase. The inclusion of solvent effects changed significantly the results obtained in gas phase, therefore this inclusion make the Z form a stationary point within all level of theory, and the relative energy depends dramatically on the level of calculation.501-505porab initioa-alaninesolventArtigo10.1590/S0100-40421999000400006S0100-40421999000400006WOS:000081587600006Acesso aberto2-s2.0-000463165862841685796170664167514050938821