Advanced concepts in electronic structure (ACES) software programs

Perera, Ajith; Bartlett, Rodney J.; Sanders, Beverly A.; Lotrich, Victor F.; Byrd, Jason N.

doi:10.1063/5.0002581

Cited by 27 publications

(31 citation statements)

References 108 publications

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“…All terms which contribute to the total coupling constant, namely, the paramagnetic spin orbit (PSO), diamagnetic spin orbit (DSO), Fermi contact (FC), and spin dipole (SD), have been evaluated. The EOM-CCSD calculations were performed using ACES II [50] on the HPC cluster Owens at the Ohio Supercomputer Center. -1 .…”

Section: Methodsmentioning

confidence: 99%

Microsolvation of the Be-F bond in complexes of BeF₂, BeF₃^–1, and BeF₄^–2with nH₂O, forn = 1–6

2021

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Ab initio MP2/aug'-cc-pVTZ calculations have been carried out to determine the structures and binding energies of complexes of BeF 2 , BeF 3 -1 , and BeF 4 -2 with n H 2 O molecules, with n = 1-6. For each series of complexes with BeF 2 , BeF 3 -1 , and BeF 4 -2 , the binding energies increase as the number of water molecules increases, but the binding energies per intermolecular bond for complexes formed between BeF 2 and BeF 4 -2 and nH 2 O decrease as the number of water molecules increases. The binding energies per bond of the BeF 3 -1 complexes show little dependence on the number of H 2 O molecules present. Intermolecular O-H ... F hydrogen bonds (HB) stabilise all complexes of H 2 O with the beryllium bases except for BeF 2 :1H 2 O and BeF 2 :2H 2 O. Complexes of BeF 2 are also stabilised by O ... Be beryllium bonds (BeB) and O-H ... O hydrogen bonds. EOM-CCSD calculations have also been performed to determine the spin-spin coupling constants. The one-bond coupling constants 1 J(Be-F) increase as the Be-F distance decreases, and exhibit an excellent second-order correlation with that distance. 2h J(O-F) coupling constants across O-H ... F hydrogen bonds also exhibit a secondorder dependence on distance. Coupling constants 1be J(O-Be) and 2h J(O-O) are found in complexes with BeF 2 and exhibit a linear dependence on the Be-O and O-O distances, respectively.

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Section: Methodsmentioning

confidence: 99%

Microsolvation of the Be-F bond in complexes of BeF₂, BeF₃^–1, and BeF₄^–2with nH₂O, forn = 1–6

2021

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“…All the methods mentioned are implemented in the development version of software packages ACES II 143,144 and Massively Parallel Quantum Chemistry (MPQC) 145,146 . To test these methods, we did a simple study of singlet excited states of small closed-shell molecules such as water, N 2 , Ne, CH 2 and BH in modified cc-pVDZ basis augmented with diffuse basis functions which were used in an earlier study by Christiansen, Sauer and co-workers 57,74 .…”

Section: Implementation and Resultsmentioning

confidence: 99%

A route to improving RPA excitation energies through its connection to equation-of-motion coupled cluster theory

Rishi

Perera

Bartlett

2020

The Journal of Chemical Physics

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We revisit the connection between equation-of-motion coupled cluster (EOM-CC) and random phase approximation (RPA) explored recently by Berkelbach [J. Chem. Phys. 149, 041103 (2018)]. We bring together various methodological aspects of these diverse treatment of ground and excited states and present a unified outlook. We present numerical results showing the equivalence that was previously proved on theoretical grounds. We then introduce new approximations in EOM-CC (and RPA) family of methods, assess their numerical performance and explore a way to reap the benefits of such a connection to improve on excitation energies. Our results suggest that addition of perturbative corrections to account for double excitations and missing exchange effects could result in significantly improved estimates.

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“…Moreover, because the orbitals fed into simulations such as discussed here are obtained from HF, which can be carried out in polynomial time, one may expect that in the fault-tolerant regime the HF step will itself need to be highly efficient, demanding quantum chemical codes developed in low level languages, such as those in Fortran and C++. [113][114][115] IV. CONCLUSIONS AND OUTLOOK Quantum computation is in its infancy, and so are its applications touching on quantum chemistry and many-body physics.…”

Section: Quantum Computermentioning

confidence: 99%

The Basics of Quantum Computing for Chemists

Claudino¹

2022

Preprint

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Advanced concepts in electronic structure (ACES) software programs

Cited by 27 publications

References 108 publications

Microsolvation of the Be-F bond in complexes of BeF₂, BeF₃^–1, and BeF₄^–2with nH₂O, forn = 1–6

Microsolvation of the Be-F bond in complexes of BeF₂, BeF₃^–1, and BeF₄^–2with nH₂O, forn = 1–6

A route to improving RPA excitation energies through its connection to equation-of-motion coupled cluster theory

The Basics of Quantum Computing for Chemists

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Advanced concepts in electronic structure (ACES) software programs

Cited by 27 publications

References 108 publications

Microsolvation of the Be-F bond in complexes of BeF2, BeF3–1, and BeF4–2with nH2O, forn = 1–6

Microsolvation of the Be-F bond in complexes of BeF2, BeF3–1, and BeF4–2with nH2O, forn = 1–6

A route to improving RPA excitation energies through its connection to equation-of-motion coupled cluster theory

The Basics of Quantum Computing for Chemists

Contact Info

Product

Resources

About

Microsolvation of the Be-F bond in complexes of BeF₂, BeF₃^–1, and BeF₄^–2with nH₂O, forn = 1–6

Microsolvation of the Be-F bond in complexes of BeF₂, BeF₃^–1, and BeF₄^–2with nH₂O, forn = 1–6