Computational Chemistry

[ 102 ]. As withthermodynamicenergy differences, i.e. energy differences not involv- ing a transition state, consistently obtain ...

Here are some correction factors that have been calculated for various func- tionals, as well as for some ab initio and semiempi ...

calculated relative intensities may be expected to be similar too. This is supported by Figs.7.4through7.7.Let’sexaminetheIRspec ...

Moments, Charges, Bond Orders, Atoms-in-Molecules......... 7.3.4 Properties Arising from Electron Distribution – Dipole Moments, ...

to be bigger than experimental, and electron correlation, through DFT or MP2, tends to lower the dipole moment, bringing it clos ...

7.3.4.2 Charges and Bond Orders The theory behind these was given in Section 5.5.4. Although it is sometimes said that charges o ...

results in Fig. 6.9, where there were some large differences between the semiem- pirical and HF/3-21G values, and even between A ...

parameter there is one qualitative discrepancy: for the cation C/OH bond the Mulliken HF bond order is essentially single (1.18) ...

been described by Stratman et al. [ 109 ]. Wiberg et al. used this implementation to study the effect of five functionals and fi ...

could be of some use in predicting UV spectra (seeionization energies and electron affinities, below). 7.3.5.2 NMR Spectra As wi ...

GIAO B3LYP/6-311þG(d,p) shifts to be in good agreement with experiment when appropriate calculated geometries were used [ 121 ]. ...

7.3.5.3 Ionization Energies and Electron Affinities: The Kohn–Sham Orbitals Ionization energies (ionization potentials) and elec ...

the IE for an orbital is the negative of the orbital energy; Section 5.5.5. By the “ionization energy” we usually mean the lowes ...

7.3.5.4 Electronegativity, Hardness, Softness and the Fukui Function: Electron Density Reactivity Indexes The idea of electroneg ...

at various places altered? This function measures changes in electron density that accompany chemical reactions, and has been us ...

also be defined with respect to internal energyUor Helmholtz free energyA (Section 5.5.2.1a) [ 146 ]. By analogy, (∂E/∂N)Z, the ...

@E @N  v ¼ EðM"Þ"EðMþÞ 2 " 0 ¼ "ðIþAÞ 2 i.e., using Eq.7.31 w¼ IþA 2 (7.32) To use this formula one can employ experimental or ...

orbitals, and for wavefunction orbitals"ELUMOof M is said to correspond to the electron affinity of M", not of M (see theionizat ...

electrons – decreases when an infinitesimal amount of electronic charge is added to it. Intuitively, a hard molecule is like a r ...

and from Eq.7.34 ¼ 1 2 @^2 E @N^2  v ¼ 1 2 @m @N  v ¼" 1 2 @w @N  v (7.38) The one-half factor is [ 150 ] to bringinto l ...