It is important to understand the effect of compression on the decay rate of ${}^7\mathrm{Be}$ because of its significance in calculating ${}^7\mathrm{Be}$ decay rate at the solar core and corresponding ${}^8\mathrm{B}$ neutrino flux. We have measured that the decay rate of ${}^7\mathrm{Be}$ is faster in the smaller spatial confinement of Pd lattice compared to the larger spatial confinement of Pb lattice by (0.82 ± 0.16)%, indicating the effect of compression on the decay rate of ${}^7\mathrm{Be}$ ion, because low and similar electron affinities of Pd and Pb cannot produce any observable effect. Similar results were observed earlier by applying high external pressure on ${}^7\mathrm{BeO}$ lattice. The density functional calculations underpredict the increase of ${}^7\mathrm{Be}$ decay rate under compression by a large factor, although they can account for the effect of electron affinity reasonably well. The unexpectedly large increase (∼1%) of ${}^7\mathrm{Be}$ decay rate under compression (25–40 GPa) compared to the state-of-the-art calculations could have implications on the calculated ${}^7\mathrm{Be}$ decay rate at the solar core.

• Received 22 October 2019
• Revised 24 January 2020
• Accepted 10 February 2020

DOI:https://doi.org/10.1103/PhysRevC.101.035801