The possibility of $1^{-}$ states above the 9.58- and 7.12-MeV states in ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ interfering with these lower states would strongly affect the ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}(\alpha , \gamma ){}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ capture cross sections near $E_{\alpha }=3.2\mathrm{}$ MeV and the inferred stellar-reaction rate. Cross sections below 3.2 MeV reported earlier have been extended to 4.1 MeV using similar techniques and overlap the previous measurement from ∼2.9 to ∼3.2 MeV.

• Received 29 July 1970

DOI:https://doi.org/10.1103/PhysRevC.2.2452