Quantum mechanical study on the structure and vibrational spectra of cyclobutanone and 1,2-cyclobutanedione

For 1,2-cyclobutanedione and cyclobutanone,we have carried out a comparative study of different methods like b3lyp,lsda,and b3pw91 of dft using 6-31g (d,p) basis set and mp2 method. on comparing these methods we find that b3pw91 method is closer to the experimental one. so by using b3pw91 method,we have made a comparative study of their structures,normal mode analysis,and other properties of the two derivatives of cyclobutane. the molecular homo,lumo composition,their respective energy gaps,and mesp contours/surfaces have also been drawn to explain the activity of 1,2-cyclobutanedione and cyclobutanone. © 2013 anoop kumar pandey et al.