Ab initio study of vibrational spectra of alanine in gas phase
نویسندگان
چکیده
The vibrational frequencies for the fundamental modes and the energies of low lying states of alanine in neutral and its zwitterionic form in gas phase have been calculated at RMP2 ab-initio level. The results so obtained have been compared with earlier theoretical calculations and experimental observations of IR and RAMAN spectrum. In the present study, it has been observed that our results are more nearer to the experimental observations than earlier Semi-empirical AM1 and ab-initio Restricted Hartree Fock and Density Functional Methods. It is also observed that unlike RHF/6-31G method of computation, Z-alanine could not maintain its zwitterion form with RMP2/6-31G method
منابع مشابه
AB Initio Study of Molecular Struture, Energetic and Vibrational Spectra of (GaN)4 Nanosemiconductor
In recent years there has been considerable interest in the structures, energies and thermodynamics of(GaN)4 clusters and it is the subject of many experimental and theoretical studies because of theirfundamental importance in chemical and physical process. All calculation of this study is carried outby Gaussian 98. Geometry optimization for (GaN)4 nanocluster are be fulfilled at B3LYP, B1LYPan...
متن کاملAn Ab initio and chemical shielding tensors calculations for Nucleotide 5’-Monophosphates in the Gas phase
Structural and magnetic properties of purine and pyrimidine nucleotides (CMP, UMP, dTMP, AMP, GMP, IMP) were studied at different levels of ab initio molecular orbital theory. These calculations were performed at the hartree-fock level and density functional B3LYP methods. Geometries were fully optimized by following Cs symmetry restrictions. The standard 6-31G** basis set which includes polari...
متن کاملAb initio and charge study of phospholipids in gas phase and solution
phospholipids are important for the biological lipid and are commonly used in biophysical studies.A quantumcalculation for two phospholipids Dipalmitoylphosphatidylethanolamine and dipalmitoylphosphatidic acidwere performed using the abinitio software. Geometry optimization structures were obtained at RHF level using3-21G, 6-31G*. These basis sets were used To understanding the effects of envir...
متن کاملAB Initio Calculations and IR Studies of Tautometric forms of Uracil and Cytosine and comparing results in different temperatures (25˚C, 37˚C and 40˚C).
In this paper,the molecular geometry for three tautomers of uracil and four tautomers of cytosine has been analyzed. vibrational IR spectra of the tautomers were investigated at HF and B3LYP level using the AB initio 6-31G* and LANL2DZ basis sets from the program package Gaussian 98 (A.7 Public Domain version). The physico-chemical and biochemical properties of uracil and cytosine are one of...
متن کاملAb Initio Calculation 29Si NMR Chemical Shift Studies on Silicate Species in Aqueous and Gas Phase
Nowadays NMR spectroscopy becomes a powerful tool in chemistry because of the NMR chemical shifts. Hartree–Fock theory and the Gauge-including atomic orbital (GIAO) methods are used in the calculation of 29Si NMR chemical shifts of various silicate species in the silicate solution as initial components for zeolite synthesis both in gas and solution phase. Calculations have been performed at geo...
متن کامل