碳原子价轨道电负性对化学键性能的影响

研究了同一类型化学键X―C的键能、键长和H―C键的酸性等性能与碳原子价轨道电负性的定量关系。结果表明,X―C键能随碳原子价轨道电负性增加而线性增大;H―C与C―C键的键长随碳原子价轨道电负性增加而线性减小;H―C的酸性随碳原子价轨道电负性增加而线性增大。因而,对结构类似的有机化合物,可以采用碳原子价轨道电负性对实验测定的化学键性能作图,判断其测定结果正确与否。     

An upgraded TOF-SIMS VG Ionex IX23LS: Study on the negative secondary ion emission of III-V compound semiconductors with prior neutral cesium deposition

A TOF-SIMS VG Ionex IX23LS with upgraded data acquisition and control system was used to study the secondary emission of negative atomic and cluster ions of non-metallic elements (P, As and Sb) upon a 19 keV Ga⁺ bombardment of non-degenerated III-V semiconductors (GaP, GaAs, GaSb, InP, InAs and InSb) with prior neutral Cs deposition from a getter dispenser. It was found that surface cesiation enhances the peak intensity of all negative ion species; in the case of atomic ions, the greatest increase (360) was observed for P⁻ emitted from InP. Such an enhancement was larger for In-based than for Ga-based compounds. We explained that in terms of an electronegativity difference between the composing atoms of III-V semiconductors. The greater electronegativity difference (bond ionicity) of In-based compounds resulted in the greater Cs-induced work function decrease leading to a higher increase in the ionization probability of secondary ions.     

A quantitative measure of bond polarity from the electron localization function and the theory of atoms in molecules

 A quantitative measure of the polarity of a bond can be obtained through combining the two complementary topological partitionings of the electron density obtained from the atoms in molecules theory, on the one hand, and the electron localization function, on the other. This requires an integration of the electron density in the atomic subbasins of a common bond electron localization basin. We present the first numerical application of the resulting topological definition of bond polarity to a set of small linear systems consisting of the FCN, HF, HCl, HBr, and NaCl molecules and the NeAr van der Waals dimer. It is shown that the findings are essentially in line with common expectation for these simple molecules, thus confirming the potential value of the novel bond polarity index for the analysis of controversial bonding situations. Additional insight is provided through the detailed investigation of fluctuations in the basin populations. Received: 10 January 2001 / Accepted 12 February 2001 / Published online: 22 May 2001     

Metal cations toxicity: An inorganic interpretation

Chemical hardness is one of the useful parameters giving information about the toxic nature of the structures. In the present work, absolute chemical hardness imparted to the science by Pearson, the hydration enthalpies, the element's electronegativity, as calculated by Batsanov (using the force constants of the bonds), the calculated electrostatic charge on the hydrated cations, the absolute radii for the metals and the effective nuclear charges, were correlated with available toxicology data for a series of metal cations (namely Hg²⁺, Cd²⁺, Cu²⁺ and K⁺) in order to obtain, from a physicochemical point of view, a better understanding of the deleterious actions of metal cations on living organisms. A series of linear curves and empirical equations were obtained, providing a convincing picture of the correlation toxicity-physical inorganic chemistry.     

有机锡化合物的光电子能谱研究

本文研究了五种有机锡化合物的光电子能谱图，讨论了影响锡原子内层ｄ轨道电子结合能化学位移的几种因素，比如，取代基的影响，基团电负性的影响。     

Thermodynamic correlations and band gap calculations in metal oxides

Thermodynamic parameters and energy-band gap of a given metal oxide, are suitable measures of its stability. For this reason, direct correlations between energy-band gap or chemical hardness, and thermodynamic parameters (e.g. standard enthalpy of formation) have been constructed for different metal oxides. Furthermore, a simple relationship to calculate values of energy-band gaps, for metal oxides, from values of their enthalpies of formation, is presented here. When tested, an appreciable number of metal oxides from s- , p- and d-blocks well obeyed the relationship, while a number of metal oxides deviated. A qualitative theoretical account for such different behaviors is presented here.     

Chemical action and chemical bonding

New chemical bonding paradigm in terms of chemical action functional and of its reformulations by means of electronegativity, linear response and density softness kernels is advanced; it makes no use of traditional molecular orbital bonding analysis while providing reliability in identifying the bonding regions through appropriate specialization of the chemical action variational (conservation) principle along the bond length.