103Rh-NMR studies in the superconductor Rh17S15

103Rh nuclear magnetic resonance (NMR) measurements have been performed in the superconductor Rh17S15 with the transition temperature TC=5.4 K. The observed 103Rh-NMR spectrum shows an asymmetric shape with several peaks, reflecting the local symmetry around each Rh site. We have identified the observed NMR lines corresponding to four different Rh sites and obtained the temperature (T) dependence of the Knight shift of 24m site. The isotropic part of the Knight shift Kiso decreases with decreasing T, indicating the existence of the electron correlation in Rh17S15. In the superconducting state, the resonance lines shift to higher frequencies owing to a decrease of the spin part of the Knight shift with negative hyperfine coupling.