Alternative definition of excitation amplitudes in multi-reference state-specific coupled cluster

Garniron, Yann; Giner, Emmanuel; Malrieu, Jean‐Paul; Scemama, Anthony

doi:10.1063/1.4980034

Cited by 12 publications

(18 citation statements)

References 42 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…82 Recently, sCI methods have demonstrated their ability to reach near FCI quality energies for small organic and transition metal-containing molecules. [83][84][85][86][87][88][89][90][91][92] To avoid the exponential increase of the size of the CI expansion, we employ the sCI algorithm CIPSI 83,93,94 (Configuration Interaction using a Perturbative Selection made Iteratively) to retain only the energetically-relevant determinants. To do so, the CIPSI algorithm uses a second-order energetic criterion to select perturbatively determinants in the FCI space.…”

Section: Selected Configuration Interaction Methodsmentioning

confidence: 99%

A Mountaineering Strategy to Excited States: Highly Accurate Reference Energies and Benchmarks

Loos

Scemama

Blondel

et al. 2018

J. Chem. Theory Comput.

Self Cite

298

100

645

View full text Add to dashboard Cite

Striving to define very accurate vertical transition energies, we perform both high-level coupled cluster (CC) calculations (up to CCSDTQP) and selected configuration interaction (sCI) calculations (up to several millions of determinants) for 18 small compounds (water, hydrogen sulfide, ammonia, hydrogen chloride, dinitrogen, carbon monoxide, acetylene, ethylene, formaldehyde, methanimine, thioformaldehyde, acetaldehyde, cyclopropene, diazomethane, formamide, ketene, nitrosomethane, and the smallest streptocyanine). By systematically increasing the order of the CC expansion, the number of determinants in the CI expansion as well as the size of the one-electron basis set, we have been able to reach near full CI (FCI) quality transition energies. These calculations are carried out on CC3/ aug-cc-pVTZ geometries, using a series of increasingly large atomic basis sets systematically including diffuse functions. In this way, we define a list of 110 transition energies for states of various characters (valence, Rydberg, n → π, π → π*, singlet, triplet, etc.) to be used as references for further calculations. Benchmark transition energies are provided at the aug-cc-pVTZ level as well as with additional basis set corrections, in order to obtain results close to the complete basis set limit. These reference data are used to benchmark a series of 12 excited-state wave function methods accounting for double and triple contributions, namely ADC(2), ADC(3), CIS(D), CIS(D), CC2, STEOM-CCSD, CCSD, CCSDR(3), CCSDT-3, CC3, CCSDT., and CCSDTQ. It turns out that CCSDTQ yields a negligible difference with the extrapolated CI values with a mean absolute error as small as 0.01 eV, whereas the coupled cluster approaches including iterative triples are also very accurate (mean absolute error of 0.03 eV). Consequently, CCSDT-3 and CC3 can be used to define reliable benchmarks. This observation does not hold for ADC(3) that delivers quite large errors for this set of small compounds, with a clear tendency to overcorrect its second-order version, ADC(2). Finally, we discuss the possibility to use basis set extrapolation approaches so as to tackle more easily larger compounds.

show abstract

Section: Selected Configuration Interaction Methodsmentioning

confidence: 99%

A Mountaineering Strategy to Excited States: Highly Accurate Reference Energies and Benchmarks

Loos

Scemama

Blondel

et al. 2018

J. Chem. Theory Comput.

Self Cite

298

100

645

View full text Add to dashboard Cite

show abstract

“…Both theories greatly improve the quality of the transition energies, but become unpractically demanding for medium and large systems. Alternatively, one can also compute very high quality transition energies for various types of excited states using selected configuration interaction (sCI) methods which have recently demonstrated their ability to reach near full CI (FCI) quality energies for small molecules . The idea behind such methods is to avoid the exponential increase of the size of the CI expansion by retaining the most energetically relevant determinants only, thanks to the use of a second‐order energetic criterion to select perturbatively determinants in the FCI space .…”

Section: Introductionmentioning

confidence: 99%

Evaluating 0–0 Energies with Theoretical Tools: A Short Review

Loos

Jacquemin

2019

ChemPhotoChem

View full text Add to dashboard Cite

For a given electronic excited state, the 0-0 energy (T 0 or T 00 ) is the simplest property allowing straightforward and physicallysound comparisons between theory and (accurate) experiment. However, the computation of 0-0 energies with ab initio approaches requires determining both the structure and the vibrational frequencies of the excited state, which limits the quality of the theoretical models that can be considered in practice. This explains why only a rather limited, yet constantly increasing, number of works have been devoted to the determination of this property. In this contribution, we review these efforts with a focus on benchmark studies carried out for both gas phase and solvated compounds. Over the years, not only as the size of the molecules increased, but the refinement of the theoretical tools has followed the same trend. Though the results obtained in these benchmarks significantly depend on both the details of the protocol and the nature of the excited states, one can now roughly estimate, in the case of valence transitions, the overall accuracy of theoretical schemes as follows: 1 eV for CIS, 0.2-0.3 eV for CIS(D), 0.2-0.4 eV for TD-DFT when one employs hybrid functionals, 0.1-0.2 eV for ADC (2) and CC2, and 0.04 eV for CC3, the latter approach being the only one delivering chemical accuracy on a near-systematic basis.[a] Dr.

show abstract

“…Recently, some of us developed a hybrid deterministic/stochastic algorithm for the computation of E (2) . 116 e main idea is to rewrite the expression of…”

Section: New Stochastic Selectionmentioning

confidence: 99%

“…Multiple external plugins were developed by the authors. For instance, one can nd a multi-reference coupled cluster program, 116,132 interfaces with the quantum Monte Carlo programs QMC=Chem, 133 QMCPack 134 and CHAMP, 135 an implementation of the shi ed-Bk method, 45 a program combining CIPSI with RSDFT, 136 a four-component relativistic RSDFT code, 137 and many others.…”

Section: The Plugin Systemmentioning

confidence: 99%

Quantum Package 2.0: An Open-Source Determinant-Driven Suite of Programs

Garniron¹,

Applencourt²,

Gasperich³

et al. 2019

Preprint

Self Cite

View full text Add to dashboard Cite

<div> <div> <div> <p> </p><div> <div> <div> <p>Quantum Package is an open-source programming environment for quantum chemistry specially designed for wave function methods. Its main goal is the development of determinant-driven selected configuration interaction (sCI) methods and multi-reference second-order perturbation theory (PT2). The determinant-driven framework allows the programmer to include any arbitrary set of determinants in the reference space, hence providing greater method- ological freedoms. The sCI method implemented in Quantum Package is based on the CIPSI (Configuration Interaction using a Perturbative Selection made Iteratively) algorithm which complements the variational sCI energy with a PT2 correction. Additional external plugins have been recently added to perform calculations with multireference coupled cluster theory and range-separated density-functional theory. All the programs are developed with the IRPF90 code generator, which simplifies collaborative work and the development of new features. Quantum Package strives to allow easy implementation and experimentation of new methods, while making parallel computation as simple and efficient as possible on modern supercomputer architectures. Currently, the code enables, routinely, to realize runs on roughly 2 000 CPU cores, with tens of millions of determinants in the reference space. Moreover, we have been able to push up to 12 288 cores in order to test its parallel efficiency. In the present manuscript, we also introduce some key new developments: i) a renormalized second-order perturbative correction for efficient extrapolation to the full CI limit, and ii) a stochastic version of the CIPSI selection performed simultaneously to the PT2 calculation at no extra cost. </p> </div> </div> </div> </div> </div> </div>

show abstract

Alternative definition of excitation amplitudes in multi-reference state-specific coupled cluster

Cited by 12 publications

References 42 publications

A Mountaineering Strategy to Excited States: Highly Accurate Reference Energies and Benchmarks

A Mountaineering Strategy to Excited States: Highly Accurate Reference Energies and Benchmarks

Evaluating 0–0 Energies with Theoretical Tools: A Short Review

Quantum Package 2.0: An Open-Source Determinant-Driven Suite of Programs

Contact Info

Product

Resources

About