摘要：The structural evolutionary behaviors of nitrogen in RbN3 have been studied up to 300 GPa using a particle swarm optimization structure searching method combined with density functional calculations. Three stable new phases with P -1, P 6/ mmm and C 2/ m structure at pressure of 30, 50 and 200 GPa are identified for the first time. The analysis of the crystal structures of three new predicated phases reveals that the transition of N3− ions goes from linear molecules to polymeric chains, benzene-like rings and then to polymeric layers induced by pressure. The electronic structures of three predicted phases reveal that the structural changes are accompanied and driven by the change of orbital hybridization of N atoms from sp to sp 2 and finally to partial sp 3. Most interestingly, the Rb atoms show obvious transition metal-like properties through the occupation of 4 d orbitals in high-pressure phases. Moreover, the Rb atoms are characterized by strong hybridization between 4 d orbitals of Rb and 2 p orbitals of N in C 2/ m structure. Our studies complete the structural evolution of RbN3 under pressure and reveal for the first time that the Rb atoms in rubidium nitride possess transition element-like properties under pressure.
