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Excited states and spectral functions within full configuration interaction quantum Monte Carlo

George H. Booth, Garnet Kin‐Lic Chan

Bulletin of the American Physical SocietyMar 21, 20130 citations

Deterministic alternatives to the full configuration interaction quantum Monte Carlo method for strongly correlated systems

Norm M. Tubman, K. Birgitta Whaley

Bulletin of the American Physical SocietyMar 17, 20170 citations

State-of-the-art molecular applications of full configuration interaction quantum Monte Carlo

Robert E. Thomas, Catherine Overy, James J. Shepherd +2 more

Bulletin of the American Physical SocietyMar 21, 20130 citations

Communication: Excited states, dynamic correlation functions and spectral properties from full configuration interaction quantum Monte Carlo

George H. Booth, Garnet Kin‐Lic Chan

In this communication, we propose a method for obtaining isolated excited states within the full configuration interaction quantum Monte Carlo framework. This method allows for stable sampling with respect to collapse to lower energy states and requires no uncontrolled approximations. In contrast with most previous methods to extract excited state information from quantum Monte Carlo methods, this results from a modification to the underlying propagator, and does not require explicit orthogonalization, analytic continuation, transient estimators, or restriction of the Hilbert space via a trial wavefunction. Furthermore, we show that the propagator can directly yield frequency-domain correlation functions and spectral functions such as the density of states which are difficult to obtain within a traditional quantum Monte Carlo framework. We demonstrate this approach with pilot applications to the neon atom and beryllium dimer.In this communication, we propose a method for obtaining isolated excited states within the full configuration interaction quantum Monte Carlo framework. This method allows for stable sampling with respect to collapse to lower energy states and requires no uncontrolled approximations. In contrast with most previous methods to extract excited state information from quantum Monte Carlo methods, this results from a modification to the underlying propagator, and does not require explicit orthogonalization, analytic continuation, transient estimators, or restriction of the Hilbert space via a trial wavefunction. Furthermore, we show that the propagator can directly yield frequency-domain correlation functions and spectral functions such as the density of states which are difficult to obtain within a traditional quantum Monte Carlo framework. We demonstrate this approach with pilot applications to the neon atom and beryllium dimer.

arXiv:1210.1650The Journal of Chemical PhysicsNov 21, 201256 citations

Local correlation treatment of excited states in quantum Monte Carlo

Habiburrahman Zulfikri

Oct 23, 20140 citations

Density matrices in full configuration interaction quantum Monte Carlo: Excited states, transition dipole moments, and parallel distribution

Nick S. Blunt, George H. Booth, Ali Alavi

We present developments in the calculation of reduced density matrices (RDMs) in the full configuration interaction quantum Monte Carlo (FCIQMC) method. An efficient scheme is described to allow storage of RDMs across distributed memory, thereby allowing their calculation and storage in large basis sets. We demonstrate the calculation of RDMs for general states by using the recently introduced excited-state FCIQMC approach [N. S. Blunt et al., J. Chem. Phys. 143, 134117 (2015)] and further introduce calculation of transition density matrices in the method. These approaches are combined to calculate excited-state dipole and transition dipole moments for heteronuclear diatomic molecules, including LiH, BH, and MgO, and initiator error is investigated in these quantities.We present developments in the calculation of reduced density matrices (RDMs) in the full configuration interaction quantum Monte Carlo (FCIQMC) method. An efficient scheme is described to allow storage of RDMs across distributed memory, thereby allowing their calculation and storage in large basis sets. We demonstrate the calculation of RDMs for general states by using the recently introduced excited-state FCIQMC approach [N. S. Blunt et al., J. Chem. Phys. 143, 134117 (2015)] and further introduce calculation of transition density matrices in the method. These approaches are combined to calculate excited-state dipole and transition dipole moments for heteronuclear diatomic molecules, including LiH, BH, and MgO, and initiator error is investigated in these quantities.

arXiv:1704.00864The Journal of Chemical PhysicsJun 26, 201754 citations

Publisher's Note: “Communication: Excited states, dynamic correlation functions and spectral properties from full configuration interaction quantum Monte Carlo” [J. Chem. Phys. 137, 191102 (2012)]

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Publisher's Note: “Communication: Excited states, dynamic correlation functions and spectral properties from full configuration interaction quantum Monte Carlo” [J. Chem. Phys. 137, 191102 (2012)]

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