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Correction for 'The development of a full range analytical interatomic potential' by X. W. Sheng et al., Phys. Chem. Chem. Phys., 2021, DOI: 10.1039/d0cp04083e.
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A chronological account is given to the development of a full range interatomic potential. Starting with a simple phenomenological model, the terms in the model are gradually modified, so that they can carry some definite physical meaning. To gain insight, a systematic, order by order interaction potential theory is developed. Conversely, this theory suggests the functional form for the potential model. At present, we have a simple interaction model that is capable of describing the van der Waals potentials of many systems from R = 0 to Râ∞.
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This study investigated the combined efficacy of slightly acidic electrolyzed water (SAEW) and UV light (UV) in improving egg internal quality (weight loss, Haugh unit, yolk index, albumen pH) over a 6-wk storage time at 25°C. Eggs were preserved after immersion for 4 min in SAEW (30 mg/L), irradiation for 4 min under a UV lamp, or a combination of SAEW and UV treatment for 4 min. The combination of SAEW and UV inhibited the deterioration of yolk index over the storage period, as well as reducing the extent of decrease in Haugh unit and of weight loss during storage at 25°C, and it was more effective than SAEW or UV alone in maintaining egg internal quality (P < 0.05). The results highlight the promising use of a SAEW and UV combination treatment to improve egg internal quality during storage.
Assuntos
Ovos , Eletrólitos , Tecnologia de Alimentos , Óvulo , Raios Ultravioleta , Água , Ácidos/farmacologia , Animais , Galinhas , Ovos/normas , Eletrólitos/farmacologia , Tecnologia de Alimentos/métodos , Concentração de Íons de Hidrogênio , Óvulo/efeitos dos fármacos , Óvulo/efeitos da radiação , Água/químicaRESUMO
The exchange energies of all homonuclear and heteronuclear alkali dimers are calculated based on the surface integral method. These results are generally in good agreement with both ab initio calculations and experimental results where available. It is also shown that the exchange energies could be fitted by an analytical expression of AR(b) exp(-cR). b and c can be calculated by two simple formulas that are only related to the ionization energies of the constituent atoms. A is the only parameter in this expression. More interestingly, it is found that the parameter A for the heteronuclear dimers could be approximated by a combining rule.
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This paper gives a natural orbital (NO) based analysis of the van der Waals interaction in (singlet) H2 at long distance. The van der Waals interaction, even if not leading to a distinct van der Waals well, affects the shape of the interaction potential in the van der Waals distance range of 5-9 bohrs and can be clearly distinguished from chemical bonding effects. In the NO basis the van der Waals interaction can be quantitatively covered with, apart from the ground state configurations (1σ(g))(2) and (1σ(u))(2), just the 4 configurations (2σ(g))(2) and (2σ(u))(2), and (1π(u))(2) and (1π(g))(2). The physics of the dispersion interaction requires and explains the peculiar relatively large positive CI coefficients of the doubly excited electron configurations (2σ(u))(2) and (1π(g))(2) (the occupancy amplitudes of the 2σ(u) and 1π(gx, y) NOs) in the distance range 5-9 bohrs, which have been observed before by Cioslowski and Pernal [Chem. Phys. Lett. 430, 188 (2006)]. We show that such positive occupancy amplitudes do not necessarily lead to the existence of zero occupation numbers at some H-H distances.
Assuntos
Hidrogênio/química , Teoria Quântica , Interações Hidrofóbicas e HidrofílicasRESUMO
Whereas a density functional that incorporates dispersion interaction has remained elusive to date, we demonstrate that in principle the dispersion energy can be obtained from a density matrix functional. In density matrix functional theory one tries to find suitable approximations to the two-particle reduced density matrix (2RDM) in terms of natural orbitals (NOs) and natural orbital occupation numbers (ONs). The total energy is then given as a function(al) of the NOs and ONs, i.e., as an implicit functional of the 1RDM. The left-right correlation in a (dissociating) bond, as well as various types of dynamical correlation, can be described accurately with a NO functional employing only J and K integrals (JK-only functional). We give a detailed analysis of the full CI wavefunction of the He(2) dimer, from which the dispersion part of the two-particle density matrix is obtained. It emerges that the entirely different physics embodied in the dispersion interaction leads to an essentially different type of exchange-correlation orbital functional for the dispersion energy (non-JK). The distinct NO functionals for the different types of correlation imply that they can be used in conjunction without problems of double counting. Requirements on the (primitive) basis set for Van der Waals bonding appear to be more modest than for other types of correlation.
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The ground state van der Waals potentials of the Hg-RG (RG = He,Ne,Ar,Kr,Xe) systems are generated by the Tang-Toennies potential model. The parameters of the model are calculated from the potentials of the homonuclear mercury and rare-gas dimers with combining rules. The predicted spectroscopic parameters for these mercury rare-gas complexes are in good agreement with available experimental values, except for Hg-He. In the repulsive and potential well regions, the predicted potential energy curves agree with the available experimental hybrid potentials, but they differ in the long range part of the potential. On the other hand, the present potentials are in agreement with the ab initio CCSD(T) calculations in the long range part of the potential, but there are some differences in the short repulsive regions. According to the present theory, the reduced potential curves of these five systems, including Hg-He, are almost identical to each other. This reduced potential curve can also describe, within a few percent, the five reduced potentials obtained from the ab initio CCSD(T) calculations. These reduced potentials have a potential bowl that is wider than that of the rare-gas dimers, but narrower than the mercury dimer.