Abstract— The Raman spectrum of olivine contained in a chip of the Twin Sisters Peak dunite shocked to 22.2 GPa is essentially identical to the spectrum of unshocked olivine in this rock. The Raman spectra of a powder of the rock shocked to 20.1 GPa and of chips shocked to 59.5 GPa and 60.7 GPa show strong and broad low‐frequency features with crests at 475 cm−1, 556 cm−1, and 572 cm−1, and strong as well as broad high‐frequency features near 1100 cm−1. We conclude that these features are most likely due to the formation of “olivine glass” with a considerable degree of three‐dimensional Si‐O‐Si linkage, having scattered domains of greatly variable grain size, internal structure, and, possibly, chemical composition. We cannot conclude with our results at hand whether olivine shocked to the highest pressures has not decomposed to very fine‐grained MgO plus an SiO2‐rich glass. We also conclude from our results that the structural changes are not likely to have formed in the laser beam of the measurement.

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Laser-induced fluorscence studies of low-lying energy states of Ni atoms isolated in Ne, Ar, and Kr matrices show that the atoms in Ne matrices are gas-like in nature, with a 3F4(3d84s2) ground state and levels only slightly perturbed by the matrix environment. The Ar and Kr matrices contain not only these gas-like atoms but also Ni atoms in a second kind of environment. The ground state of these atoms is 3D3(3d94s1), which we estimate lies about 200 cm−1 below 3F4.