Using the Becke's exchange in conjunction with Lee-Yang-Parr's correlation functional and Becke's three-parameter hybrid method (B3LYP), the ab initio and DFT calculations were carried out to study the optimized molecular fundamental vibrational frequencies for uracil and 5-aminouracil by employing Gaussian-03 program. 
Gaussian-03
The optimized molecular geometries, atomic polar tensor (APT) charges and vibrational characteristics have been studied theoretically using restricted Hartree-Fock (RHF) and density functional theory (DFT) methods.  The fundamental vibrational frequencies along with their corresponding intensities in IR and Raman activities and depolarization ratios of the Raman lines have also been calculated using the RHF and DFT methods employing different basis sets. 
RHF
The optimized molecular geometries, atomic polar tensor (APT) charges and vibrational characteristics have been studied theoretically using restricted Hartree-Fock (RHF) and density functional theory (DFT) methods.  Using the Becke's exchange in conjunction with Lee-Yang-Parr's correlation functional and Becke's three-parameter hybrid method (B3LYP), the ab initio and DFT calculations were carried out to study the optimized molecular fundamental vibrational frequencies for uracil and 5-aminouracil by employing Gaussian-03 program.  The fundamental vibrational frequencies along with their corresponding intensities in IR and Raman activities and depolarization ratios of the Raman lines have also been calculated using the RHF and DFT methods employing different basis sets. 
DFT
Using the Becke's exchange in conjunction with Lee-Yang-Parr's correlation functional and Becke's three-parameter hybrid method (B3LYP), the ab initio and DFT calculations were carried out to study the optimized molecular fundamental vibrational frequencies for uracil and 5-aminouracil by employing Gaussian-03 program.  In quantum chemical calculations, the most of B3LYP/6-311++G** vibrational frequencies are in the excellent agreement with available experimental assignments and helped in the reassignments of some fundamental vibrational modes. 
B3LYP
In quantum chemical calculations, the most of B3LYP/6-311++G** vibrational frequencies are in the excellent agreement with available experimental assignments and helped in the reassignments of some fundamental vibrational modes. 
6-311++G**