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Abstract
Methods where an accurate wavefunction is embedded in a densityfunctional description of the surrounding environment have recently been simplified through the use of a projection operator to ensure orthogonality of orbital subspaces. Projector embedding already offers significant performance gains over conventional postHartreeFock methods by reducing the number of correlated occupied orbitals. However, in our first applications of the method, we used the atomicorbital basis for the full system, even for the correlated wavefunction calculation in a small, active subsystem. Here, we further develop our method for truncating the atomicorbital basis to include only functions within or close to the active subsystem. The number of atomic orbitals in a calculation on a fixed active subsystem becomes asymptotically independent of the size of the environment, producing the required O (N 0) scaling of cost of the calculation in the active subsystem, and accuracy is controlled by a single parameter. The applicability of this approach is demonstrated for the embedded manybody expansion of binding energies of water hexamers and calculation of reaction barriers of S<inf>N</inf>2 substitution of fluorine by chlorine in αfluoroalkanes.
Original language  English 

Article number  024105 
Journal  Journal of Chemical Physics 
Volume  143 
Issue number  2 
DOIs  
Publication status  Published  14 Jul 2015 
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Dive into the research topics of 'Accelerating wavefunction in densityfunctionaltheory embedding by truncating the active basis set'. Together they form a unique fingerprint.Projects
 2 Finished

Scalable electronic structure theory: the embedded electronpair approximation
1/05/13 → 1/05/16
Project: Research
