In this paper, we have examined analytical spectrometry using Eu Lg 4 . The oxidation-state-fluctuating compound EuPd 2 Si 2 exhibits the largest temperature-induced valence changes among all Eu systems and does not have a structural phase transition below 298 K; EuPd 2 Si 2 has a precipitous valence transition near 150 K. Hence, high-resolution Eu Lg 4 emission spectra of EuPd 2 Si 2 at 298 K and 30 K were measured using a multicrystal multidetector spectrometer. The spectra exhibited substantial differences, thereby indicating that the spectral shapes of Eu Lg 4 emissions depend on the oxidation state of the Eu ions. We have also demonstrated the applicability of Eu Lg 4 emission to oxidation state selective extended X-ray absorption fine structure (EXAFS) spectroscopy through partial fluorescence yield measurements with an excitation energy range of approximately 0.5 keV. In this manner, we have addressed and resolved two key questions in analytical spectrometry using Eu Lg 4 .