A5049009844- Advanced Chemical Physics Studies
- Spectroscopy and Quantum Chemical Studies
- Perovskite Materials and Applications
- Catalytic Processes in Materials Science
- Machine Learning in Materials Science
- Spectroscopy and Laser Applications
- Molecular Junctions and Nanostructures
- Cold Atom Physics and Bose-Einstein Condensates
- Quantum Computing Algorithms and Architecture
- 2D Materials and Applications
- Quantum Dots Synthesis And Properties
- Quantum Information and Cryptography
- Thermal Radiation and Cooling Technologies
- Strong Light-Matter Interactions
- Mass Spectrometry Techniques and Applications
- Laser-Matter Interactions and Applications
- Advanced Physical and Chemical Molecular Interactions
- Atomic and Molecular Physics
- Quantum chaos and dynamical systems
- Catalysis and Oxidation Reactions
University of California, Berkeley
2017-2020
QMCPACK is an open source quantum Monte Carlo package for ab initio electronic structure calculations. It supports calculations of metallic and insulating solids, molecules, atoms, some model Hamiltonians. Implemented real space algorithms include variational, diffusion, reptation Carlo. uses Slater–Jastrow type trial wavefunctions in conjunction with a sophisticated optimizer capable optimizing tens thousands parameters. The orbital auxiliary-field method also implemented, enabling cross...
We present a mean field theory for excited states that is broadly analogous to ground state Hartree-Fock theory. Like Hartree-Fock, our approach deterministic, state-specific, applies variational principle minimally correlated ansatz, produces energy stationary points, relaxes the orbital basis, has Fock-build cost-scaling, and can serve as foundation correlation methods such perturbation coupled cluster To emphasize this last point, we pair with an analogue of second order Moller-Plesset...
We present a generalization of the variational principle that is compatible with any Hamiltonian eigenstate can be specified uniquely by list properties. This appears to wide range electronic structure methods, including mean field theory, density functional multireference and quantum Monte Carlo. Like standard principle, this generalized amounts optimization nonlinear function that, in limit an arbitrarily flexible wave function, has desired as its global minimum. Unlike it target excited...
We present a method for finding individual excited states' energy stationary points in complete active space self-consistent field theory that is compatible with standard optimization methods and highly effective at overcoming difficulties due to root flipping near-degeneracies. Inspired by both the maximum overlap recent progress excited-state variational principles, our approach combines these ideas order track states throughout orbital process. In series of tests involving flipping,...
We demonstrate that a broad class of excited state variational principles is not size consistent. In light this difficulty, we develop and test an approach to optimization transforms between achieve selectivity, consistency, compatibility with quantum Monte Carlo. To complement our formal analysis, provide numerical examples confirm these properties how they contribute more black box states in
We explore the performance of a recently introduced N5-scaling excited-state-specific second order perturbation theory (ESMP2) on singlet excitations Thiel benchmarking set. find that, without regularization, ESMP2 is quite sensitive to π system size, performing well in molecules with small systems but poorly those larger systems. With far less size and shows higher overall accuracy set than CC2, equation motion-coupled cluster singles doubles, CC3, wide variety time-dependent density...
We show that by working in a basis similar to of the natural transition orbitals and using modified zeroth-order Hamiltonian, cost recently introduced perturbative correction excited-state mean field theory can be reduced from seventh fifth order system size. The (occupied)2(virtual)3 asymptotic scaling matches ground-state second-order Møller-Plesset but with significantly higher prefactor because bottleneck is iterative: it appears Krylov-subspace-based solution linear equation yields...
We explore the performance of a recently-introduced $N^5$-scaling excited-state-specific second order perturbation theory (ESMP2) on singlet excitations Thiel benchmarking set. find that, without regularization, ESMP2 is quite sensitive to $π$ system size, performing well in molecules with small systems but poorly those larger systems. With far less size and shows higher overall accuracy set than CC2, EOM-CCSD, CC3, wide variety time-dependent density functional approaches. Unsurprisingly,...
We demonstrate that a broad class of excited state variational principles is not size consistent. In light this difficulty, we develop and test an approach to optimization transforms between in order achieve selectivity, consistency, compatibility with quantum Monte Carlo. To complement our formal analysis, provide numerical examples confirm these properties how they contribute more black box states
We present a generalization of the variational principle that is compatible with any Hamiltonian eigenstate can be specified uniquely by list properties. This appears to wide range electronic structure methods, including mean-field theory, density functional multi-reference and quantum Monte Carlo. Like standard principle, this generalized amounts optimization nonlinear function that, in limit an arbitrarily flexible wave function, has desired as its global minimum. Unlike it target excited...
We present a method for finding individual excited states' energy stationary points in complete active space self-consistent field theory that is compatible with standard optimization methods and highly effective at overcoming difficulties due to root flipping near-degeneracies. Inspired by both the maximum overlap recent progress state variational principles, our approach combines these ideas order track states throughout orbital process. In series of tests involving flipping,...