Institute of Chemistry

The static dipole and quadrupole moments, as well as various higher polarizability tensors, are calculated for the BeS molecule using various coupled cluster (CC) variants with the inclusion of single and double excitation operators (CCSD) and an a posteriori approximate treatment of the triples (CCSD(T)). Moreover, full inclusion of the singles, doubles and triples (CCSDT) is employed for dipole moment and dipole polarizability calculations, for which also the fifth-order non-iterative corrections are analysed in detail. The important role of electron correlation effects is stressed. A comparison of values calculated as energy derivatives with values obtained as expectation values and/or expectation value derivatives is made. This comparison confirms that as soon as the triples are included both methods provide similarly reliable results.

Accurate TDDFT calculations of the dipole moment l and components of the dipole polarizability a for the ground and lowest excited states of uracil have been performed with a variety of functionals. It has been found that the functionals with corrected asymptotic behavior like LC-BLYP, xB97XD, and CAM-B3LYP yield more consistent and reliable data than standard hybrid ones. The results of the TDDFT calculations agree well with more elaborate and expensive linear response CCSD calculations. Excess polarizability Da for the singlet states is larger than for the triplet states. .pl (M. Kolaski), miroslav.medved@umb.sk (M. Medved'), simon.budzak@umb.sk (Š. Budzák).

Convergence patterns and limiting values of isotropic nuclear magnetic shieldings were studied for several small molecules (N 2 , CO, CO 2 , NH 3 , CH 4 , C 2 H 2 , C 2 H 4 , C 2 H 6 , and C 6 H 6 ) in the Kohn-Sham limit. Individual results of calculations using dedicated families of Jensen's basis sets (pcS-n and pcJ-n) were fitted toward the complete basis set limit (CBS) using a simple two-parameter formula. Several density functionals were used; calculated vibrational corrections (ZPV) applied; and, for comparison purposes, similar calculations performed using RHF, MP2, SOPPA, SOPPA(CCSD), and CCSD(T) methods and additionally, the aug-cc-pVTZ-J basis set. Finally, the CBS estimated results were critically compared with earlier reported literature data and experimental results. Among 42 studied DFT methods, the KTn and "pure" functionals produced the most accurate heavy atom isotropic nuclear shieldings. easy to find accurate values of experimental nuclear shieldings in the gas phase. 32 For example, the experimental value of water oxygen shielding was recently significantly revisedsfrom 344 ( 17.2 33 to 323.6 34 and 323.5 ( 6 ppm. The latter value has been currently modified to 325.3 ( 3 ppm. Unfortunately, currently available density functionals are usually semiempirical, calibrated mainly on energy of selected molecular systems. 28 Thus, there is an open question in the literature of which density functional provides the most accurate nuclear shieldings. And, is there a unique density functional, or a group of well performing ones, in predicting NMR properties in the Kohn-Sham limit? Therefore, a selection of high-quality DFT functional(s) for prediction of nuclear shieldings is of vital importance for a wide community, currently using predominantly B3LYP as the method of choice.

The performance of more than 40 density functionals in predicting indirect spin−spin coupling constants (SSCCs) in the Kohn− Sham basis set limit was tested. For comparison, similar calculations were performed using the RHF, SOPPA, SOPPA(CC2), and SOPPA(CCSD) methods, and the results were estimated toward the complete basis set (CBS) limit. The SSCCs of nine small molecules (N 2 , CO, CO 2 , NH 3 , CH 4 , C 2 H 2 , C 2 H 4 , C 2 H 6 , and C 6 H 6 ) were calculated using the dedicated Jensen pcJ-n polarization-consistent basis sets and used for the CBS limit estimations within the Kohn−Sham limit. These CBS results were compared with calculations using the aug-cc-pVTZ-J basis set. Among the 41 studied DFT methods, the tHCTHhyb, HSEh1PBE, HSE2PBE, wB97XD, wB97, and wB97X functionals reproduced accurately the experimental 1 J(XH) SSCCs and 3 J(HH60) and 2 J(HH gem ) in ethane. Similarly, the functionals HSEh1PBE, HSE2PBE, wB97XD, wB97, and wB97X predicted accurately 1 J(CC), and B98, B97-1, B97-2, PBE1PBE, B1LYP, and O3LYP provided accurate 1 J(CO) results in the CO molecule. A very good performance for the calculation of the SSCCs based on the use of the relatively small basis set aug-cc-pVTZ-J was observed.

The aim of our study was to highlight the benefits of robust calibration in the context of process control. Two properties were monitoredthe color and ash content of sugar samples. It was shown for the data being studied that robust models, constructed using the partial robust M-regression technique, have a better fit to the majority of the data and prediction properties than the classic partial least squares and N-way partial least squares models. In particular, the constructed calibration models were characterized by a root mean square errors improved by 1.60% and 1.82% and a root mean square errors of prediction (for independent test samples) improved by 2.39% and 1.11% compared to classic partial least squares models constructed for color and ash content, respectively.

The aim of this work was to propose a quick and cost-effective procedure, which could help to identify the types of fat (rapeseed, a mixture of rapeseed and soybean, and lard oils) added to feed used for raising pigs. For this purpose, liver samples were examined and their near-infrared reflectance spectra served as data for the construction of classic and robust soft independent modeling of class analogy (SIMCA) models. The results showed that the near-infrared reflectance spectra contained information sufficient to build good classification models that enabled three types of fat additions to be distinguished. The best classification results were obtained from robust SIMCA, indicating its superior performance in terms of high sensitivity and specificity in comparison with classic SIMCA. Specifically, robust models had sensitivities of 100% and specificities of 96.05%, 97.73% and 100%, for rapeseed, mixture of rapeseed and soybean, and lard enriched feed, respectively.