Pulse laser-heating results showing the time delay of the collected light from 180 to 100 GPa. The pulse laser is focused on the sample from side 1 (see Fig. 1). (a), (b), (c) Plots of near-IR intensity collected from the sample versus time (in ns) at 180 GPa, 140 GPa and 100 GPa, respectively. Red points are collected from side 1 (laser-heating side) and green points from side 2. The black curves are the pseudo-Voigt fits for the curve obtain from side 1, with black dashed curves for side 2. The time delay is calculated using the position of the two FWHMs for each side as illustrated in (a). (d) Plots of the inverse delay (in ns−1) (left scale) at the three investigated pressures (red circles); also reported are the results for thermal conductivity of molten iron (right-hand scale) as a function of pressure (blue squares) (Pozzo et al., 2012).