Nuclear reactivity and nuclear stiffness in density functional theory

Ordon, Piotr; Komorowski, Ludwik

doi:10.1016/s0009-2614(98)00645-9

Cited by 38 publications

(49 citation statements)

References 23 publications

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“…This approach involves a response function characterizing the response of an atom or a molecule to perturbations, the latter being usually the number of the electrons and/or the external potential during the course of a chemical reaction [7]. On the basis of the idea of response functions, Cohen et al [8,9] and, afterwards, Ordon and Komorowski defined nuclear Fukui functions [10,11]. The nuclear reactivity U i and the nuclear stiffness G i were then defined, respectively, as the variation of the electronegativity and the variation of the molecular hardness on molecular deformation.…”

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confidence: 99%

Nuclear fukui functions and the deformed atoms in molecules representation of the electron density: Application to gas‐Phase RDX (hexahydro‐1,3,5‐trinitro‐1,3,5‐ triazine) electronic structure and decomposition

Moraes

Borges

2011

Int J of Quantum Chemistry

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ABSTRACT:The electronic structure and the onset of decomposition processes of the four conformers of the RDX molecule were studied through the density functional theory (DFT) along with the B3LYP functional and the 6-311þG(2d,p) Gaussian basis set. The computed DFT electron density was decomposed into atomic contributions using the deformed atoms in molecules (DAM) method, which allowed us to identify regions of electron accumulation and electron depletion of each conformer. The nuclear Fukui functions nuclear stiffness and nuclear reactivity index were then calculated. Both functions are atomic vectors, intrinsic molecular properties, which provide information for the onset of the fragmentation process, were further discussed through the analysis of the DAM electron density. The computed, decomposed electronic structures indicate that equatorial (E) NO 2 (nitro) groups are less bulky than axial (A) groups, with the Additional Supporting Information may be found in the online version of this article. former contributing more than the latter to the increase of the ring delocalized electrons and, therefore, to the lower stability of conformers with more E groups. Concerning the decomposition, the RDX NANO 2 bond cleavage is the most probable process for the AAA, AEE, and EEE conformers, while for the AAE conformer, HONO elimination is favored in partial agreement with previous study.

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confidence: 99%

Nuclear fukui functions and the deformed atoms in molecules representation of the electron density: Application to gas‐Phase RDX (hexahydro‐1,3,5‐trinitro‐1,3,5‐ triazine) electronic structure and decomposition

Moraes

Borges

2011

Int J of Quantum Chemistry

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“…The nuclear reactivity and nuclear stiffness for a rigid structure (unperturbed by oscillation, ␣,o and G ␣,o ), are readily calculated from the forces, as shown in previous works [6,9]. In accord with the harmonic level of approximation (neglecting the anharmonicity) the thermal average of force has been introduced as F ␣ ϭ Ϫk ␣ ͗Q ␣ 2 ͘ 1/ 2 , whereas the force constants k ␣ and the ␣ were assumed to be independent on the nuclear displacements Q ␣ , well in accord with the map of the derivatives presented in Table I.…”

Section: Resultsmentioning

confidence: 99%

“…The necessary data were taken from: Refs. [6] (, G, and ), [11] (k, , and ), and [10] ( ). The G and values employed here are the derivatives, without the 1/2 factor frequently used in older works, the source data have been multiplied accordingly.…”

Section: Resultsmentioning

confidence: 99%

“…This derivative, also known as the nuclear Fukui function [3], soon attracted attention. Independently, Berkowitz et al [4], Baekelandt [5], and Ordon and Komorowski [6] proved it to be equal to the derivative of the chemical potential (, or the negative of electronegativity, ) over the nuclear displacement; the numerical values thereof have also been ascribed [6]. Balawender and Geerlings [7] discerned the nucleophilic and electrophilic ⌽ i and provided a computational ab initio scheme for this quantity.…”

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confidence: 99%

“…The counterpart to the nuclear reactivity, the nuclear softness, was introduced by Cohen et al [2] as i ϭ (ѨF i /Ѩ) ; the numerical values were ascribed to it by De Proft et al [8]. The derivative of global hardness () was introduced by Ordon and Komorowski as the nuclear stiffness: G i ϭ (Ѩ/ѨQ i ) N [6]. The authors also presented analysis of ⌽ i and G i indices for normal vibrational modes [9] and elaborated on the role of these indices in determining the fluctuations in chemical potential (electronegativity) and hardness due to molecular oscillations [9,10].…”

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DFT energy derivatives and their renormalization in molecular vibrations

Ordon

Komorowski

2004

Int J of Quantum Chemistry

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ABSTRACT:Properties of the energy function E(N, Q) and the thermodynamic potential ⍀(, Q) expressed in terms of the number of electrons (N) and the nuclear positions (Q) rather than conventionally, by the electrostatic potential, (r), have been analyzed. The whole body of derivatives up to the third order is presented for each function. Renormalization of the basic derivatives explored in conceptual density functional theory has been demonstrated (chemical potential , global hardness , number of electrons N, global softness S) as a result of coupling between the oscillatory motion of nuclei and the change in N or , for E and ⍀, respectively. Exact result of renormalization crucially depends on the level of approximation. Extending the analysis beyond the second order was possible by adopting the Liu and Parr-type approximation to the energy function. It has been determined that first derivatives (, N) change their values when found beyond the vibrational energy minimum only. Second derivatives (, S) both get renormalized even at the energy minimum, and they no longer conform to the reciprocity condition (S 1). Possible implications for the reactivity of oscillating species have been indicated.

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Chemical Reactivity Within the Spin‐Polarized Framework of Density Functional Theory

Chamorro

Pérez²

2021

Chemical Reactivity in Confined Systems

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Nuclear reactivity and nuclear stiffness in density functional theory

Cited by 38 publications

References 23 publications

Nuclear fukui functions and the deformed atoms in molecules representation of the electron density: Application to gas‐Phase RDX (hexahydro‐1,3,5‐trinitro‐1,3,5‐ triazine) electronic structure and decomposition

Nuclear fukui functions and the deformed atoms in molecules representation of the electron density: Application to gas‐Phase RDX (hexahydro‐1,3,5‐trinitro‐1,3,5‐ triazine) electronic structure and decomposition

DFT energy derivatives and their renormalization in molecular vibrations

Chemical Reactivity Within the Spin‐Polarized Framework of Density Functional Theory

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