Pionic fusion reactions ${}_{}{}^4{}_{}{}^{}\mathrm{He}$,${\pi }^{+}$${)}^7$Li and ${}_{}{}^4{}_{}{}^{}\mathrm{He}$,${\pi }^0$${)}^7$Be at the subthreshold energy are studied theoretically. The cross section is enhanced largely by the clustering correlation. The general trend of target-mass dependence of the A${(}^3$He,${\pi }^{+}$)C reaction is also studied.

• Received 14 November 1986

DOI:https://doi.org/10.1103/PhysRevC.35.1370