Progesterone and testosterone studies by neutron scattering and nuclear magnetic resonance methods and quantum chemistry calculations

Inelastic incoherent neutron scattering spectra of progesterone and testosterone measured at 20 and 290 K were compared with the IR spectra measured at 290 K. The Phonon Density of States spectra display well resolved peaks of low frequency internal vibration modes up to 1200 cm21. The quantum chemistry calculations were performed by semiempirical PM3 method and by the density functional theory method with different basic sets for isolated molecule, as well as for the dimer system of testosterone. The proposed assignment of internal vibrations of normal modes enable us to conclude about the sequence of the onset of the torsion movements of the CH3 groups. These conclusions were correlated with the results of proton molecular dynamics studies performed by NMR method. The GAUSSIAN program had been used for calculations. q 2004 Elsevier B.V. All rights reserved.