摘要
HHe^(+)is considered as the strongest acid and most powerful proton donor known to human.Whether HHe^(+)exists at planetary high pressure environment is a quite important problem in physics,chemistry and planetary sciences.Here,using the ab initio evolutionary algorithm USPEX package,we searched HF–He system,which was reported as the most possible candidate to contain HHe^(+).The calculation proved HHe^(+)cannot form at pressure<1000 GPa,due to a conflict between the covalent component in symmetric hydrogen bond and ionic HHe^(+).Although He atoms have no chemical bonding with other elements,they can supply a chemical pressure,leading to two new phases He2(HF)4 and He(HF).With coplanar(HF)_(4)rings,He_(2)(HF)_(4)have an aromaticity-like electronic behavior while He(HF)has a new type of chiral HF chain.The formation of He_(2)(HF)_(4)and He(HF)prove that the chemical pressure from He,on par with external pressure,have ability to control the structural and electronic configuration and induce some new familiars of compounds include H and He elements which are fundamental planetary materials in giant planets.
基金
NSFC(Grants No.21803033)
Yong Elite Scientists Sponsorship Program by Tianjin(Grant No.TJSQNTJ-2018-18)
the support by doctor foundation of Tianjin Normal University(52XB1911).