An investigation of electron momentum spectroscopy on the 9a1 and 5b2 orbitals of thiophene

The electron momentum spectra of outer va- lence orbitals 9a1+5b2 of thiophene (C4H4S) have been stud- ied by binary (e, 2e) electron momentum spectroscopy (EMS), at an impact energy of 1200 eV plus binding energy, and symmetric non-coplanar kinematics. The experimental mo- mentum profile of the summed orbitals is compared with the theoretical momentum distributions calculated using Har- tree-Fock (HF) and density functional theory (DFT) methods with various basis sets. The experimental measurement is well described by the HF and DFT calculations, and the cal- culations using the larger basis sets including diffuse and polarization functions give better descriptions of experi- ments.