The origin and distance dependence of the electronic interactions which promote energy transfer within photosynthetic light-harvesting complexes is investigated. A model based on localized molecular orbitals is related to canonical molecular orbital calculations, therefore demonstrating its practical utility and allowing us to interpret the results of CAS-SCF calculations of the coupling betwee...

Background Since the success rate in older poor-responder (POR) infertile women is expected to be extremely low irrespective of the treatment protocol, clinicians continue the search for biomarkers which may predict cases in which proceeding with follicle aspiration may be appropriate. Experimental studies on murine model suggest that SCF(Stem- Cell-Factor) produced by ovarian cumulus granulosa...

The quasi-degenerate perturbation theory (QDPT) with complete active space (CAS) self-consistent field (SCF) reference functions is extended to the general multiconfiguration (MC) SCF references functions case. A computational scheme that utilizes both diagrammatic and sum-over-states approaches is presented. The second-order effective Hamiltonian is computed for the external intermediate confi...

Medium sized basis sets of Gaussian Lobe functions for use in SCF-MO calculations are presented. With these, computations are performed on the hydrides of the atoms Li —F. Partly, mixed bases are applied in which the one-electron integrals are calculated with respect to a more extensive basis than the two-electron integrals. The energy shifts caused by shortening of the bases are separated into...

The ab initio scalar ZORA approach, which was previously tested within the context of numerical and basis set SCF calculations, is generalized to include electron correlation. The technical details of the method are investigated in calculations on the systems Ne2, Ar2, Kr2 and Xe2. For the weakly bonded rare gas dimers we calculated the bond lengths and well depths using the non-relativistic ZO...

The photoelectron (PE) spectra of 2,2'-bipyridine 1, 2 ,2 ' :6 ' ,2"-terpyridine 2, and 2,2 ' ,2" ,2" / tetrapyridine 3 have been measured using H e I radiation. For 1 — 3 standard SCF LCAO MO calculations wer also performed. Comparison of P E spectra and these calculations allowed the assignment o f Ti-ionizations and indirectly also the nitrogen lone pair ionizations in 1 — 3. Factors influen...

Photodissociation of acetic acid in the gas phase was investigated using ab initio molecular orbital methods. The stationary structures on the ground-state potential energy surfaces were mainly optimized at the MP2 level of theory, while those on the excited-state surfaces were determined by complete active space SCF calculations with a correlation-consistent basis set of cc-pVDZ. The reaction ...

Recently developed density functionals have good accuracy for both thermochemistry (TC) and non-covalent interactions (NC) if very large atomic orbital basis sets are used. To approach the basis set limit with potentially lower computational cost, a new self-consistent field (SCF) scheme is presented that employs minimal adaptive basis (MAB) functions. The MAB functions are optimized on each at...

Ionization potentials (IPs) and electron affinities (EAs) are important quantities input into most models for calculating the open-circuit voltage (Voc) of organic solar cells. We assess the semi-empirical density-functional tight-binding (DFTB) method with the third-order self-consistent charge (SCC) correction and the 3ob parameter set (the third-order DFTB (DFTB3) organic and biochemistry pa...

The long-held “shielding cone” model of the through-space NMR shielding effect of a carbon-carbon double bond predicts only the effect of the magnetic anisotropy of the double bond; it ignores other important contributors to the overall shielding. GIAO-SCF and GIAO-MP2 calculations have been performed on a simple model system, methane moved sequentially above ethene or 2-methylpropene. These ca...