Momentum profile and final correlation effects of iso-butane inner valenceby binary (e, 2e) spectroscopy

The binding energy spectra and the momentum distributions of the valence or bitals of iso-butane, also known as methylpropane (CH3 CH(CH3)CH3), are stu died by using a high resolution binary (e, 2e) electron momentum spectromet er, at an impact energy of 1200 eV plus the binding energy (8-32 cV) with s ymmetric non-coplanar kinematics. Binding energy spectra of the valence she ll are obtained at a coincidence energy resolution of 0.95 eV in fill width at half maximum. The experimental momentum profiles of the inner valence o rbitals are obtained and compared with the theoretical momentum distributio ns calculated by using Hartree-Fock and density functional theory methods w ith the basis sets 6-31G and 6-311++G** The pole strengths of the inner orb itals are estimated and the final correlation effects are discussed.