On the other hand, the ELNES/XANES spectroscopic method has a significant limitation. The ELNES/XANES reflect the excitation of core electrons to the conduction bands, which is a process that generates core holes and consequently shifts electron orbitals towards lower energy levels. This implies that the orbitals involved in transitions are not in their ground state but in their excited state, making ELNES/XANES spectral shapes reflect the DOS of the conduction band in the excited state. Furthermore, since the electronic transition obeys the selection rule of dipole transitions, change in an orbital's angular momentum number is limited to Δl=±1. Therefore, the ELNES/XANES does not provide information on all orbitals but only yield limited PDOS related to the specific orbitals. In other words, it is not possible to obtain the electronic structure of both the valence and conduction bands for all orbitals in the ground state directly from the ELNES/XANES, while the ground-state electronic structure is more crucial for understanding the stability and properties of materials.