Hyperconjugative Effect on the Electronic Wavefunctions of Ethanol
  Hyperconjugation is a basic conception of chemistry. Its straightforward effect is exhibited by the spatial delocalization characteristics of the electron density distributions or wavefunctions. Such effects on the electron wavefunctions of the highest-occupied molecular orbitals (HOMO) of two ethanol conformers are demonstrated with electron momentum spectroscopy together with natural bond orbital analyses, exhibiting the distinctly different symmetries of the HOMO wavefunctions in momentum space. 
Xiangjun Chen (*), Fang Wu, Mi Yan, Hai-Bei Li, Shan Xi Tian*, Xu   Shan, Kedong Wang, Zhongjun Li, and Kezun Xu