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Related papers: Analytic Computation of Vibrational Circular Dichr…

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Recent advances in selected CI, including the adaptive sampling configuration interaction (ASCI) algorithm and its heat bath extension, have made the ASCI approach competitive with the most accurate techniques available, and hence an…

Quantum chemistry is one of the most promising applications for which quantum computing is expected to have significant impact. Despite considerable research in the field of electronic structure, calculating the vibrational properties of…

Quantum Physics · Physics 2025-05-23 Marco Majland , Patrick Ettenhuber , Nikolaj Thomas Zinner , Ove Christiansen

We introduce an analytical framework to calculate the values of key observables in a strongly disordered discrete time crystal (DTC) without fitting parameter. The perturbatively obtained closed-form formulae show quantitative agreement…

Disordered Systems and Neural Networks · Physics 2025-12-25 Yang-Ren Liu , Biao Huang

We present an implementation of the B term of Magnetic Circular Dichroism within the Algebraic Diagrammatic Construction (ADC) scheme of the polarization propagator and its Intermediate State Representation. As illustrative results, the MCD…

Using the ground-state energy of 16-O obtained with the realistic V_UCOM interaction as a test case, we present a comprehensive comparison of different configuration interaction (CI) and coupled-cluster (CC) methods, analyzing the intrinsic…

Nuclear Theory · Physics 2009-06-30 R. Roth , J. R. Gour , P. Piecuch

Rotation-vibration spectra of the nitric acid molecule, HNO\3, are calculated for wavenumbers up to 7000~\cm. Calculations are performed using a Hamiltonian expressed in internal curvilinear vibrational coordinates solved using a hybrid…

Chemical Physics · Physics 2015-04-13 A. I. Pavlyuchko , S. N. Yurchenko , Jonathan Tennyson

We use empirical molecular dynamics technique to study the low-energy vibrations in a large 4096 atom model for pure amorphous silicon and a set of models with voids of different size based on it. Numerical vibrational eigenvalues and…

Disordered Systems and Neural Networks · Physics 2009-10-31 Serge M. Nakhmanson , D. A. Drabold

Configuration Interaction (CI) calculations on the ground state of the C atom are carried out using a small basis set of Slater orbitals [7s6p5d4f3g]. The configurations are selected according to their contribution to the total energy. One…

Atomic Physics · Physics 2017-08-01 María Belén Ruiz , Robert Tröger

To avoid the combinatorial computational cost of configuration interaction (CI), we have previously introduced the symmetric tensor decomposition CI (STD-CI) method, where we take advantage of the antisymmetric nature of the electronic wave…

Chemical Physics · Physics 2015-06-24 Wataru Uemura , Shusuke Kasamatsu , Osamu Sugino

Recalling that the rotating wave approximation (RWA) is only valid in the weak coupling regimes, the purpose of this paper is to study the Hamiltonian dynamics describing the full quantum mechanical approach of the interaction between…

Quantum Physics · Physics 2021-08-17 N. Asili Firouzabadi , M. K. Tavassoly

We present the first implementation and applications of non-Dyson algebraic diagrammatic construction theory for charged excitations in three-dimensional periodic solids (EA/IP-ADC). The EA/IP-ADC approach has a computational cost similar…

Materials Science · Physics 2022-11-15 Samragni Banerjee , Alexander Yu. Sokolov

Numerical simulations to evaluate thoracic aortic hemodynamics include a computational fluid dynamic (CFD) approach or fluid-structure interaction (FSI) approach. While CFD neglects the arterial deformation along the cardiac cycle by…

We present a fully variational generalization of the pseudo self-interaction correction (VPSIC) approach previously presented in two implementations based on plane-waves and atomic orbital basis set, known as PSIC and ASIC, respectively.…

Materials Science · Physics 2015-05-28 A. Filippetti , C. D. Pemmaraju , P. Delugas , D. Puggioni , V. Fiorentini , S. Sanvito

We compare two recently developed strategies, implemented in open source software packages, for computing linear optical spectra in condensed phase environments in the presence of nonadiabatic effects. Both approaches rely on computing…

Chemical Physics · Physics 2024-08-14 Evan Lambertson , Dayana Bashirova , Kye E. Hunter , Benhardt Hansen , Tim J. Zuehlsdorff

We derive analytical nuclear gradients for state-averaged orbital-optimized configuration interaction singles (SACIS) and its spin-projected extension (SAECIS), enabling efficient geometry optimization and minimum-energy conical…

Chemical Physics · Physics 2026-04-15 Takashi Tsuchimochi

We present and test an approximate method for the semiclassical calculation of vibrational spectra. The approach is based on the mixed time-averaging semiclassical initial value representation method, which is simplified to a form that…

Chemical Physics · Physics 2018-03-22 Max Buchholz , Frank Grossmann , Michele Ceotto

The time-dependent restricted-active-space self-consistent-field (TD-RASSCF) method is formulated based on the TD variational principle. In analogy with the configuration-interaction singles (CIS), singles-and-doubles (CISD),…

Quantum Physics · Physics 2014-06-26 Haruhide Miyagi , Lars Bojer Madsen

For computational acoustics, schemes need to have low-dispersion and low-dissipation properties in order to capture the amplitude and phase of the wave correctly. To improve the spectral properties of the scheme, the authors have previously…

Computational Physics · Physics 2021-11-15 Y. H. Li , Y. X. Ren , Y. T. Su

The computation of the nuclear quantum dynamics of molecules is challenging, requiring both accuracy and efficiency to be applicable to systems of interest. Recently, theories have been developed for employing time-dependent basis functions…

In this work, we present a time-dependent (TD) selected configuration interaction method based on our recently-introduced adaptive configuration interaction (ACI). We show that ACI, in either its ground or excited state formalisms, is…

Chemical Physics · Physics 2020-01-08 Jeffrey B. Schriber , Francesco A. Evangelista