Search

We update the Quadratic Integrand Double-Hybrid (QIDH) model [J. Chem. Phys. 141, 031101 (2014)] by incorporating the nonempirical restored-regularized Strongly Constrained and Appropriately Normed (r2SCAN) meta-generalized gradient approximation exchange-correlation functional, thus devising a robust density functional approximation free of any empirical parameter and incorporating all the constraints so far known for the exchange-correlation kernel. We assessed the new r2SCAN-QIDH expression on the GMTKN55 database and further extend its application to various types of non-covalent interactions (e.g., S66 × 8, O24 × 5). The assessment done shows that the model becomes very competitive in accuracy with respect to parent exchange-correlation functionals of any type, but without relying on any fitted parameter or numerical training. [ABSTRACT FROM AUTHOR]

The effective calculation of static nonlinear optical properties requires a considerably high accuracy at a reasonable computational cost, to tackle challenging organic and inorganic systems acting as precursors and/or active layers of materials in (nano‐)devices. That trade‐off implies to obtain very accurate electronic energies in the presence of externally applied electric fields to consequently obtain static polarizabilities (αij) and hyper‐polarizabilities (βijk and γijkl). Density functional theory is known to provide an excellent compromise between accuracy and computational cost, which is however largely impeded for these properties without introducing range‐separation techniques. We thus explore here the ability of a modern (double‐hybrid and range‐separated) Range‐Separated eXchange Quadratic Integrand Double‐Hybrid exchange‐correlation functional to compete in accuracy with more costly and/or tuned methods, thanks to its robust and parameter‐free nature. [ABSTRACT FROM AUTHOR]

A family of non-empirical double-hybrid (DH) density functionals, such as Perdew–Burke–Ernzerhof (PBE)0-DH, PBE-QIDH, and their range-separated exchange (RSX) versions RSX-0DH and RSX-QIDH, all using Perdew-Burke-Ernzerhof(PBE) exchange and correlationfunctionals, is applied here to calculate the excitation energies for increasingly longer linear and cyclic acenes as part of their intense benchmarking for excited states of all types. The energies for the two lowest-lying singlet 1La and 1Lb states of linear oligoacenes as well as the triplet 3La and 3Lb states, are calculated and compared with experimental results. These functionals clearly outperform the results obtained from hybrid functionals and favorably compare with other double-hybrid expressions also tested here, such as B2-PLYP, B2GP-PLYP, ωB2-PLYP, and ωB2GP-PLYP. The study is complemented by the computation of adiabatic S0–T1 singlet-triplet energy difference for linear acenes as well as the extension of the study to strained cyclic oligomers, showing how the family of non-empirical expressions robustly leads to competitive results. [ABSTRACT FROM AUTHOR]

The energy difference (ΔEST) between the lowest singlet (S1) state and the triplet (T1) excited state of a set of azaphenalene compounds, which is theoretically and experimentally known to violate Hund's rule, giving rise to the inversion of the order of those states, is calculated here with a family of double-hybrid density functionals. That excited-state inversion is known to be very challenging to reproduce for time-dependent density functional theory employing common functionals, e.g., hybrid or range-separated expressions, but not for wavefunction methods due to the inclusion of higher-than-single excitations. Therefore, we explore here if the last developed family of density functional expressions (i.e., double-hybrid models) is able to provide not only the right excited-state energy order but also accurate ΔEST values, thanks to the approximate inclusion of double excitations within these models. We herein employ standard double-hybrid (B2-PLYP, PBE-QIDH, and PBE0-2), range-separated (ωB2-PLYP and RSX-QIDH), spin-scaled (SCS/SOS-B2PLYP21, SCS-PBE-QIDH, and SOS-PBE-QIDH), and range-separated spin-scaled (SCS/SOS-ωB2-PLYP, SCS-RSX-QIDH, and SOS-RSX-QIDH) expressions to systematically assess the influence of the ingredients entering into the formulation while concomitantly providing insights for their accuracy. [ABSTRACT FROM AUTHOR]

Copyright of Revista Iberoamericana de Ciencias de la Actividad Física y el Deporte is the property of Revista Iberoamericana de Ciencias de la Actividad Física y el Deporte and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this work, we focus on the understanding of the driving force behind the S1–T1 excited-state energy inversion (which would thus violate Hund's rule, making the S1 state lower in energy than the T1 state) of two non-benzenoid non-alternant hydrocarbons, composed of odd-membered rings. The molecules considered here have identical chemical composition but different atomic configuration in space. The delicate interplay between structural and electronic factors that might induce inversion and its energy extension, only by a few meV, is systematically investigated here by state-of-the-art calculations. Qualitative and quantitative accurate predictions are obtained employing post-HF methods, thanks to the balanced and careful inclusion of electron correlation effects. The obtained results might guide and rationalize new searches for molecules violating Hund's rule, concomitantly demonstrating the importance of key contributions from the theoretical method of choice. [ABSTRACT FROM AUTHOR]

This study aimed to characterize the physical-chemical and biological properties of pectin (PC)/chia seed mucilage (CM) membranes. PC/CM [100/0 (control), 80/20%, 60/40%, and 40/60% w/w] membranes were prepared using the casting method. The membranes (PC/CM) were thin, yellow, lightly opaque (≈10%) and capable of blocking light UVB (between 66 at 52%). SEM analysis showed the presence of aggregates in the shape of a sphere (≈13 µm) and ovoid (≈25 µm). The proportion of 80/20 showed an increase in tensile strength (29%) and elastic modulus (19%) when compared to the control. FTIR analysis exhibited intermolecular interactions between PCPC, PC-CM, and CM-CM in the membranes. The thermal analysis (600°C) showed a slight improvement in the percentage of residual mass-loss of 3.31% (80/20) that control. The 40/60 membrane showed the lowest percentage of hemolysis (2.94%) but limited human albumin adsorption capacity. These results suggested that the blend PC/CM may be considered as a biomaterial for medical applications. [ABSTRACT FROM AUTHOR]