title: Atomic scale mechanism of the transformation of gamma-alumina to theta-alumina.
abstract: gamma-alumina is known to transform to theta-alumina and finally to alpha-alumina upon thermal treatment with a catastrophic loss of porosity and catalytic activity. First-principles calculations were performed to investigate the atomic scale mechanism of the gamma- to theta-alumina transformation. The transformation pathways between the two different forms have been mapped out and identified as a sequence of Al cation migrations. Different possible Al migration paths may be responsible for the experimentally observed formation of domains and twins in theta-alumina. The estimated temperature dependence of the conversion rate is in excellent agreement with the experimental transformation temperature.
authors.affiliation: Department of Physics, State Key Laboratory for Physical Chemistry of Solid Surface, Xiamen University, Xiamen 361005, People's Republic of China.
authors.forename: Shu-Hui
authors.initials: SH
authors.lastname: Cai
authors.forename: Sergey N
authors.initials: SN
authors.lastname: Rashkeev
authors.forename: Sokrates T
authors.initials: ST
authors.lastname: Pantelides
authors.forename: Karl
authors.initials: K
authors.lastname: Sohlberg