Real‐time time‐dependent electronic structure theory

Goings, Joshua J.; Lestrange, Patrick J.; Li, Xiaosong

doi:10.1002/wcms.1341

Cited by 159 publications

(202 citation statements)

References 187 publications

(382 reference statements)

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“…76,122 The resulting theory represents a cost-efficient alternative to time-dependent CI 12,[123][124][125] and allows one to simulate the electron dynamics for systems that are currently targeted by approximate approaches such as real-time time-dependent density functional theory. [126][127][128] In the present formulation of the TD-DMRG algorithm, the local basis set is fixed during the whole propagation. A simultaneous optimization of both the CI coefficients, expressed as MPS, and of the local basis in a self-consistent-field fashion could enhance the efficiency of TD-DMRG.…”

Section: Resultsmentioning

confidence: 99%

Large-Scale Quantum Dynamics with Matrix Product States

Baiardi

Reiher

2019

J. Chem. Theory Comput.

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Dynamical electronic-and vibrational-structure theories have received a growing interest in the last years due to their ability to simulate spectra recorded with ultrafast experimental techniques. The exact time evolution of a molecular system can, in principle, be obtained from the time-dependent version of full configuration interaction.Such an approach is, however, limited to few-atom systems due to the exponential increase of its cost with the system dimension. In the present work, we overcome this unfavorable scaling by employing the time-dependent density matrix renormalization group (TD-DMRG) which parametrizes the time-dependent wavefunction as a matrix product state. The time-dependent Schrödinger equation is then integrated with a sweep-based algorithm, as in standard time-independent DMRG. Unlike other TD-DMRG approaches, the one presented here leads to a set of coupled equations that can be integrated exactly. The resulting theory enables us to study real-and imaginarytime evolutions of Hamiltonians comprising more than 20 degrees of freedom that are challenging for current state-of-the-art quantum dynamics algorithms. We apply our algorithm to the simulation of quantum dynamics of models of increasing complexity, ranging from simple excitonic Hamiltonians to more complex ab-initio vibronic ones.

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Section: Resultsmentioning

confidence: 99%

Large-Scale Quantum Dynamics with Matrix Product States

Baiardi

Reiher

2019

J. Chem. Theory Comput.

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“…This article improves upon our previous work by providing and assessing a procedure for reducing the computational cost of electron dynamics calculation using the GDF method, which is combined with the real-time timedependent density functional theory (RT-TDDFT) [3][4][5][6] under the adiabatic approximation for electron functionals.…”

Section: Introductionmentioning

confidence: 90%

Electron dynamics method using a locally projected group diabatic Fock matrix for molecules and aggregates

Yonehara

Nakajima

2020

Chemical Physics

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We propose a method using reduced size of Hilbert space to describe an electron dynamics in molecule and aggregate based on our previous theoretical scheme [ T. Yonehara and T. Nakajima, J. Chem. Phys. 147, 074110 (2017) ]. The real-time time-dependent density functional theory is combined with newly introduced projected group diabatic Fock matrix. First, this projection method is applied to a test donor-acceptor dimer, namely, a naphthalene-tetracyanoethylene with and without initial local excitations and light fields. Secondly, we calculate an absorption spectrum of five-unit-polythiophene monomer. The importance of feedback of instantaneous density to Fock matrix is also clarified. In all cases, half of the orbitals were safely reduced without loss of accuracy in descriptions of properties. The present scheme provides one possible way to investigate and analyze a complex excited electron dynamics in molecular aggregates within a moderate computational cost.

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“…Formally, Equation may be solved (propagated) exactly in the time domain through the Magnus expansion of the time‐domain propagator,

P ((), t) = U ((),, t, t_{0}) P ((), t_{0}) U {(t, t_{0})}^{†}, U ((),, t, t_{0}) = \exp ((), normalΩ ((),, t, t_{0}))

where Ω( t , t 0 ) is a nonterminating series expansion which must be truncated in practice. Many explicit and implicit time integration methods may be derived from the Magnus expansion of the propagator of which ChronusQ implements a functional subset. The default integration scheme in ChronusQ is the modified midpoint unitary transformation (MMUT) method of Li et al .…”

Section: Current Program Featuresmentioning

confidence: 99%

The Chronus Quantum software package

Williams‐Young

Petrone

Sun

et al. 2019

WIREs Comput Mol Sci

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The Chronus Quantum (ChronusQ) software package is an open source (under the GNU General Public License v2) software infrastructure which targets the solution of challenging problems that arise in ab initio electronic structure theory. Special emphasis is placed on the consistent treatment of time dependence and spin in the electronic wave function, as well as the inclusion of relativistic effects in said treatments. In addition, ChronusQ provides support for the inclusion of uniform finite magnetic fields as external perturbations through the use of gauge‐including atomic orbitals. ChronusQ is a parallel electronic structure code written in modern C++ which utilizes both message passing implementation and shared memory (OpenMP) parallelism. In addition to the examination of the current state of code base itself, a discussion regarding ongoing developments and developer contributions will also be provided. This article is categorized under: Software > Quantum Chemistry Electronic Structure Theory > Ab Initio Electronic Structure Methods Electronic Structure Theory > Density Functional Theory

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Real‐time time‐dependent electronic structure theory

Cited by 159 publications

References 187 publications

Large-Scale Quantum Dynamics with Matrix Product States

Large-Scale Quantum Dynamics with Matrix Product States

Electron dynamics method using a locally projected group diabatic Fock matrix for molecules and aggregates

The Chronus Quantum software package

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