摘要：The present communication is aimed at comparing the molecular structural properties, vibrational and energetic data of ortho, meta and para hydroxybenzaldehyde, in gas phase, due to their commercial importance. The ground state properties of the title molecules have been calculated employing DFT/ B3LYP level of theory using the 6-311++G(d,p) basis set. The mean polarizability of all the three isomers are found to be nearly same in the range 88.415 to 90.933/a.u., but the dipole moment for ortho and meta hydroxybenzaldehyde are calculated to be 5.0201 and 4.9101 Debye whereas the dipole moment for para hydroxybenzaldehyde has slightly lower value at 3.4655 Debye. The first static hyperpolarizability of 'p'- hydroxybenzaldehyde is found to be 1.5 times higher to that of 'm'-hydroxybenzaldehyde and 5 times higher than 'o'- hydroxybenzaldehyde. MESP surfaces have also been drawn and compared. In order to obtain a complete description of molecular dynamics, vibrational wavenumber calculation along with the normal mode analysis, have been carried out at the DFT level. The calculated spectra of the molecules agree well with the experimental data.
