Electronic structures of organic salt DMTSA-BF₄ using photoelectron spectromicroscopy

The electronic structures of organic salt DMTSA-BF₄, where DMTSA is 2,3-dimethyltetraseleno-anthracene, have been studied with photoelectron spectromicroscopy at various photon energies. The atomic orbital characters of the spectral features observed in the valence band region were determined from the photon energy dependence of the photoionization cross-section. The features between approximately 1 and approximately 4 eV are predominantly derived from both Se 4p and C 2p states. The features at approximately 6 eV, between approximately 7 and approximately 10 eV, and between approximately 10 and approximately 20 eV are predominantly derived from Se 4p, C 2p, and Se 4s and/or C 2s states, respectively. The F 2p states originating from the counter anion BF₄ are located at approximately 8 eV. By comparing the Se 3d core-level photoemission spectra between DMTSA-BF₄ and DMTSA, it is suggested that DMTSA-BF₄ has a mixed valence state.