title: Optimized energy landscape exploration using the ab initio based activation-relaxation technique.
abstract: Unbiased open-ended methods for finding transition states are powerful tools to understand diffusion and relaxation mechanisms associated with defect diffusion, growth processes, and catalysis. They have been little used, however, in conjunction with ab initio packages as these algorithms demanded large computational effort to generate even a single event. Here, we revisit the activation-relaxation technique (ART nouveau) and introduce a two-step convergence to the saddle point, combining the previously used Lanczós algorithm with the direct inversion in interactive subspace scheme. This combination makes it possible to generate events (from an initial minimum through a saddle point up to a final minimum) in a systematic fashion with a net 300-700 force evaluations per successful event. ART nouveau is coupled with BigDFT, a Kohn-Sham density functional theory (DFT) electronic structure code using a wavelet basis set with excellent efficiency on parallel computation, and applied to study the potential energy surface of C(20) clusters, vacancy diffusion in bulk silicon, and reconstruction of the 4H-SiC surface.
authors.affiliation: Nanosciences Foundation, 23 rue des martyrs, 38000 Grenoble, France.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Machado-Charry
authors.forename: Laurent Karim
authors.initials: LK
authors.lastname: Béland
authors.forename: Damien
authors.initials: D
authors.lastname: Caliste
authors.forename: Luigi
authors.initials: L
authors.lastname: Genovese
authors.forename: Thierry
authors.initials: T
authors.lastname: Deutsch
authors.forename: Normand
authors.initials: N
authors.lastname: Mousseau
authors.forename: Pascal
authors.initials: P
authors.lastname: Pochet
mesh_terms: D017554:Carbon Compounds, Inorganic / Q000737:chemistry; D003198:Computer Simulation; D037741:Fullerenes / Q000737:chemistry; D008956:Models, Chemical; D011789:Quantum Theory; D012825:Silicon / Q000737:chemistry; D017655:Silicon Compounds / Q000737:chemistry; D013499:Surface Properties
chemical_list: D017554:Carbon Compounds, Inorganic; D037741:Fullerenes; D017655:Silicon Compounds; C022088:silicon carbide; D012825:Silicon