Γ- and α-Ce phase diagram: First-principle calculation*Project supported by the National Natural Science Foundation of China (Grant Nos. 11272293 and U1230201), the Defense Industrial Technology Development Program (Grant No. B1520132001), and the Foundation of National Key Laboratory of Shock Wave and Detonation Physics of China (Grant No. 9140C670301140C67283). (20th January 2016)