Figure 10
The changes in the electronic structure of PA with increasing pressure. (a) Predicted shrinking of the HOCO–LUCO band gap; the bars represent band gap extent; the colors approximate the expected sample color at a given pressure. (b) Microscopy images of a PA crystal in a DAC (gasket diameter ∼400 µm, taken from ca 0.01 GPa to ca 5.0 GPa at regular intervals of ∼0.45 GPa; gradual darkening of the sample indicates a change in the solid-state absorption spectrum. (c) Calculated electronic density of states and band structure plots for PA in the vicinity of HOCO–LUCO band gap: without external pressure (left), at 3 GPa (middle) and at 10 GPa (right). |