On the nature of the melting line of bcc sodium

Recent experiments have obtained the melting line of sodium up to pressures of about 130 GPa, finding that the melting line from the {\em bcc} phase reaches a maximum at a temperature of {\em c.a.} 1000 K and a pressure of 31 GPa, and at higher pressures the fusion temperature decreases continuously up to 118 GPa. Here we report results of a study based on first principles molecular dynamics, clarifying the nature of the maximum and subsequent decreasing behavior found in the melting line of sodium.