Second-Order Analytic Derivatives for XYG3 Type of Doubly Hybrid Density Functionals: Theory, Implementation, and Application to Harmonic and Anharmonic Vibrational Frequency Calculations

2021 ◽  
Author(s):  
Yonghao Gu ◽  
Zhenyu Zhu ◽  
Xin Xu
Keyword(s):  
Vibrational Frequency ◽  
Second Order ◽  
Density Functionals

scholarly journals Simplified Tuning of Long-Range Corrected Density Functionals for Use in Symmetry-Adapted Perturbation Theory

2021 ◽  
Author(s):  
Montgomery Gray ◽  
John Herbert
Keyword(s):  
Perturbation Theory ◽  
Asymptotic Behavior ◽  
Long Range ◽  
System Size ◽  
Second Order ◽  
Density Functionals ◽  
Hole Making ◽  
Large Systems ◽  
Automated Tuning ◽  
Order Dispersion

Long considered a failure, second-order symmetry-adapted perturbation theory (SAPT) based on Kohn-Sham orbitals, or SAPT(KS), can been resurrected for semiquantitative purposes using long-range corrected (LRC) density functionals whose asymptotic behavior is adjusted separately for each monomer. As in other contexts, correct asymptotic behavior can be enforced via "optimal tuning" of LRC functionals, based on the ionization energy theorem, but the tuning procedure is tedious, expensive for large systems, and comes with a troubling dependence on system size. Here, we show that essentially identical results are obtained using an automated tuning procedure based on the size of the exchange hole, making tuned "SAPT(wKS)" fast and convenient. In conjunction with SAPT-based methods that sidestep second-order dispersion, this procedure achieves benchmark-quality interaction energies, along with the usual SAPT energy decomposition, without the hassle of system-specific tuning.

scholarly journals Simplified Tuning of Long-Range Corrected Density Functionals for Use in Symmetry-Adapted Perturbation Theory

2021 ◽  
Author(s):  
Montgomery Gray ◽  
John Herbert
Keyword(s):  
Perturbation Theory ◽  
Asymptotic Behavior ◽  
Long Range ◽  
System Size ◽  
Second Order ◽  
Density Functionals ◽  
Hole Making ◽  
Large Systems ◽  
Automated Tuning ◽  
Order Dispersion

Long considered a failure, second-order symmetry-adapted perturbation theory (SAPT) based on Kohn-Sham orbitals, or SAPT(KS), can been resurrected for semiquantitative purposes using long-range corrected (LRC) density functionals whose asymptotic behavior is adjusted separately for each monomer. As in other contexts, correct asymptotic behavior can be enforced via "optimal tuning" of LRC functionals, based on the ionization energy theorem, but the tuning procedure is tedious, expensive for large systems, and comes with a troubling dependence on system size. Here, we show that essentially identical results are obtained using an automated tuning procedure based on the size of the exchange hole, making tuned "SAPT(wKS)" fast and convenient. In conjunction with SAPT-based methods that sidestep second-order dispersion, this procedure achieves benchmark-quality interaction energies, along with the usual SAPT energy decomposition, without the hassle of system-specific tuning.

scholarly journals Wavefunction stability analysis without analytical electronic Hessians: application to orbital-optimised second-order Møller–Plesset theory and VV10-containing density functionals

2015 ◽  
Vol 113 (13-14) ◽  
pp. 1802-1808 ◽  
Author(s):  
Shaama Mallikarjun Sharada ◽  
David Stück ◽  
Eric J. Sundstrom ◽  
Alexis T. Bell ◽  
Martin Head-Gordon
Keyword(s):  
Stability Analysis ◽  
Second Order ◽  
Density Functionals ◽  
Moller Plesset

scholarly journals Benchmarking Density Functionals on First Row Transition Metal Fluorides (ScF−MnF)

2019 ◽  
Vol 9 (2S2) ◽  
pp. 298-303
Keyword(s):  
Transition Metal ◽  
Bond Length ◽  
Vibrational Frequency ◽  
Mean Deviation ◽  
Metal Fluoride ◽  
Density Functionals ◽  
Metal Fluorides ◽  
The Mean ◽  
Transition Metal Fluorides ◽  
Theoretical Results

In this work, we have assessed the performances of ten density functionals for the bond length, vibrational frequency and bond dissociation energy values of first row transition metal fluorides (TMFs). The selected density functionals are, TPSSh, B3LYP, B97, PBE0, ɷB97X, ɷB97X-D, M05, M05-2X, M06 and M06-2X respectively. The obtained results are in agreement with the previous experimental or theoretical results. From this study, it is found that the mean deviation in the metal-fluoride bond length is in the range of 0.01−0.06 Å and the mean deviation in the metal-fluoride bond energy is in the range of 0.16−0.74 eV. Based on this study, we suggest that the B3LYP, TPSSh, B97 and PBE0 functionals can produce good results for selected metal fluoride systems and will be recommended for the above systems.

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