It is shown that the response of molecular properties of diatomics such as the total energy, the bond length, and the vibrational Stark shift to an external homogenous electric field (EF) can be predicted from field-free observable properties such as the equilibrium bond length, the bond dissociation energy, the polarizability and dipole moment functions, and the vibrational frequency. Delley [...

ion saddle 6-311G(d ,p) 6-3111G(3d f ,2p) 97.2 90.1 6-3111G(2d f ,2pd) 94.7 88.8 6-31111G(2d f ,2pd) 94.5 88.6 6-31111G(3d f ,2pd) 95.3 89.0 6-31111G(3d f ,3pd) 95.3 88.8 aug-cc-pVTZ 92.7 85.8 aug-cc-pV5Z ̄ 89.5 OH1H2 6-311G(d ,p) 6-3111G(3d f ,2p) 67.5 63.0 6-3111G(2d f ,2pd) 68.4 65.0 6-31111G(2d f ,2pd) 68.3 64.9 6-31111G(3d f ,2pd) 68.9 65.2 6-31111G(3d f ,3pd) 69.0 65.5 aug-cc-pVTZ 66.6 63....

Short-chain branching in polyethylene, which involves a six-centre transition state, is studied by ab initio quantum mechanics up to the QCISD(T) level. The calculation gives a (low-pressure) activation energy of 73 kJ mol and a frequency factor of 4:8 × 10 s: The frequency factor for this six-centre transition state is expected to be of acceptable accuracy and also applicable to homologous sys...

The isomerization of silylallene to seven of its isomers has been studied using ab initio molecular orbital theory. The energetics were obtained using quadratically convergent configuration interaction (QCISD(T)) with the 6-311G(d,p) basis set, at geometries optimized by second-order perturbation theory (MP2) with the 6-31G(d) basis set. Test calculations using multiconfiguration wave functions...

The structural and energetic characteristics of O3–H2O complexes have been investigated by means of B3LYP, MP2, MP4(SDTQ), CCSD(T) and QCISD(T) methods in conjunction with the AUG-cc-pVDZ and AUG-cc-pVTZ basis sets. Six conformers were found for the O3–H2O complex. Two different intermolecular interactions were expected to participate in the formation of complexes, namely conventional O∙∙∙H hyd...

The results of MNDO, AM1 and PM3 semi-empirical calculations and HF/6-31G*, MP/6-31G*, MP2/6-311+G**, and B3LYP/6-311G** and QCISD/6-31G* ab initio methods for angle strain and conjugation effects in twist-boat, boat, and half-chair geometries of (Z,Z,Z)-cycloocta-1,3,5-triene indicate that all methods, except PM3, predict wrong ordering of the conformations.

Recently, a combined laser ablation and density functional theory study (Jiang and Xu, J. Am. Chem. Soc. 2005, 127, 8906) claimed the existence of the long-sought 18-electron member of the first-row transition metal carbonyl complex, Zn(CO)(3). In this paper, we systematically investigate the thermodynamic and kinetic stability of Zn(CO)(3) towards CO-extrusion at the BP86, B3PW91, BPW91, PBEPB...

Four implicit potential energy surfaces (PESs) with specific-reaction-parameters (SRP) are developed and tested for the reaction CH4 + H → CH3 + H2. The first is called MPW60 and is based on the modified Perdew-Wang (mPW) hybrid density-functional method with the percentage of Hartree-Fock (HF) exchange equal to 60%. The other three PESs are constructed with multi-coefficient correlation method...