Binary encounter model for the electron impact K‐shell ionization of atoms

The electron impact K‐shell ionization (EIKSI) cross sections on 18 atomic targets, with the atomic numbers 2 ≤ Z ≤ 92, are calculated using a modified version of the binary encounter approximation (BEA) model. The modified BEA (MBEA), which incorporates both ionic and relativistic corrections and is simpler in application than other existing models, is found to be immensely successful in describing the EIKSI data up to the incident energy of 1 GeV. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2008     

Specific fragmentation of the K‐shell excited/ionized pyridine derivatives studied by electron impact: 2‐, 3‐ and 4‐methylpyridine

Fragmentation of the pyridine ring upon K‐shell excitation/ionization has been studied with gaseous 2‐, 3‐ and 4‐methylpyridine by the electron‐impact method. Ab initio molecular orbital (MO) calculations were also carried out to explore electronic states correlating with specific fragments. Some specific fragmentation channels were identified from the ionic fragments enhanced characteristically at the N 1s edge. Yields of the C₂HN⁺ and C₅H₅⁺/C₅H₆⁺ ions show that the fission of the N? C2 and C4? C5/C5? C6 bonds of the ring is likely to occur after the N 1s excitation and ionization. Ab initio MO calculations for the 2‐methylpyridine molecule indicate that the dissociation channels to produce these ions are only accessible through the excited states of the parent molecular dication, which can be formed by Auger decays after the N 1s ionization. Fragment ions via hydrogen rearrangement are produced as well, but the rearrangement is not a phenomenon specific to the K‐shell excitation/ionization. Copyright © 2010 John Wiley & Sons, Ltd.     

DFT,CBS‐Q,W1BD and G4MP2 calculation of the proton and electron affinities,gas phase basicities and ionization energies of saturated and unsaturated carboxylic acids (C1–C4)

The proton affinities, gas phase basicities and ionization energies of formic acid, acetic acid, propanoic acid, 2‐propenoic acid, propiolic acid, butanoic acid, 2‐butenoic acid, 3‐botenoic acid, 2‐methyl‐propanoic acid and 2‐methyl‐2‐propenoic acid were calculated using the computational methods including B3LYP/6‐311++G(2df,p), CBS‐Q and G4MP2. Also, the considered properties were calculated using W1BD method only for formic and acetic acids. In addition, the electron affinities of the acids were calculated using B3LYP, CBS‐Q, G4MP2 and G2MP2 methods, separately. The calculations showed that the PA and gas phase basicity increase with the increase in the number of carbon atoms. The calculated Ionization energies of the unsaturated carboxylic acids are less than the corresponding saturated acids, which are in good agreement with the experimental results. © 2013 Wiley Periodicals, Inc.     

Fabrication of covalently functionalized mesoporous silica core–shell magnetite nanoparticles with palladium(II) acetylacetonate: application as a magnetically separable nanocatalyst for Suzuki cross‐coupling reaction of acyl halides with boronic acids

We report the preparation of supported palladium(II) acetylacetonate, Pd(acac)₂, coordinated by pendant acac groups, by reacting palladium acetate with acac‐functionalized doubly silica‐coated magnetic nanoparticles. The solid support consists of an amorphous silica‐coated (as magnetite protecting layer) magnetite core and a mesoporous silica shell. The magnetically separable palladium nanocatalyst is active for Suzuki cross‐coupling reaction of acyl halides with boronic acids. The catalyst is simply isolated from the reaction mixture that allows fast and efficient isolation of product and catalyst compared to traditional methods that generally make use of time‐ and solvent‐consuming procedures. Copyright © 2015 John Wiley & Sons, Ltd.