THEORETICAL STUDY OF THE 2s2p$^{4}$ RESONANCE STATE IN THE PHOTODETACHMENT OF C$^{-}$ BY THE R-MATRIX METHOD Nobuaki Miura$^\ast$, Fukashi Sasaki$^{\dag}$ and Takeshi Noro$^\sharp$ $^\ast$National Institute of Materials and Chemical Research, Tsukuba, Japan $^\dag$Tomakomai Komazawa University , Tomakomai, Japan $^\sharp$Hokkaido University , Sapporo, Japan Phtodetachment cross sections were calculated for the 2s$^{2}$2p$^{3}$ ($^{4}$S$^{o}$) state of C$^{-}$ by using the R-matrix method. The resultant cross sections were in good agreement with the available experiments. We found that the peak for the 2s2p$^{4}$ ($^{4}$P) resonance state is located at 6.9eV.