Sobre la ocurrencia del cretáceo superior marino en Coihaique , Provincia de Aisén

Using the CCSD­(T) model, we evaluated the intermolecular potential energy surfaces of the He–, Ne–, and Ar–phosgene complexes. We considered a representative number of intermolecular geometries for which we calculated the corresponding interaction energies with the augmented (He complex) and double augmented (Ne and Ar complexes) correlation-consistent polarized valence triple-ζ basis sets extended with a set of 3s3p2d1f1g midbond functions. These basis sets were selected after systematic basis set studies carried out at geometries close to those of the surface minima. The He–, Ne–, and Ar–phosgene surfaces were found to have absolute minima of −72.1, −140.4, and −326.6 cm^–1 at distances between the rare-gas atom and the phosgene center of mass of 3.184, 3.254, and 3.516 Å, respectively. The potentials were further used in the evaluation of rovibrational states and the rotational constants of the complexes, providing valuable results for future experimental investigations. Comparing our results to those previously available for other phosgene complexes, we suggest that the results for Cl₂–phosgene should be revised

Phase Transformation Mechanism of Li-Ion Storage in Iron(III) Hydroxide Phosphates

Many ion storage compounds used for electrodes in Li-ion batteries undergo a first order phase transformation between the Li-rich and Li-poor end-members during battery charge and discharge. This often entails large transformation strains due to lattice misfits, which may hamper charge and discharge kinetics. Iron­(III) hydroxide phosphate, Fe_2–<i>y</i>(PO₄)­(OH)_{3–3<i>y</i>}(H₂O)_{3<i>y</i>−2} is a promising new cathode material with high Li-ion storage capacity, low production costs and low toxicity. Previous reports on this material indicate that the Li-ion intercalation and extraction in this material is accompanied by a second-order solid solution transformation. However, direct information about the transformation mechanism in Fe_2–<i>y</i>(PO₄)­(OH)_{3–3<i>y</i>}(H₂O)_{3<i>y</i>−2} is lacking, and several details remain unclear. In this work, Fe_2–<i>y</i>(PO₄)­(OH)_{3–3<i>y</i>}(H₂O)_{3<i>y</i>−2} is prepared by hydrothermal synthesis and characterized structurally, morphologically and by electrochemical analysis (galvostatic cycling and cyclic voltammetry). A wide range of synthesis conditions is screened, which provides information about their correlation with chemical composition, crystallite size, particle morphology and electrochemical performance. The phase transformation mechanism of selected materials is investigated through synchrotron radiation powder X-ray diffraction collected during galvanostatic discharge–charge cycling. This confirms a complete solid solution transformation both during Li-insertion (discharge) and -extraction (charge), but also reveals a highly anisotropic evolution in lattice dimensions, which is linked to an irreversible reaction step and the high vacancy concentration in Fe_2–<i>y</i>(PO₄)­(OH)_{3–3<i>y</i>}(H₂O)_{3<i>y</i>−2}

Small and Efficient Basis Sets for the Evaluation of Accurate Interaction Energies: Aromatic Molecule–Argon Ground-State Intermolecular Potentials and Rovibrational States

By evaluating a representative set of CCSD­(T) ground state interaction energies for van der Waals dimers formed by aromatic molecules and the argon atom, we test the performance of the polarized basis sets of Sadlej et al. (<i>J. Comput. Chem.</i> <b>2005</b>, <i>26</i>, 145; <i>Collect. Czech. Chem. Commun.</i> <b>1988</b>, <i>53</i>, 1995) and the augmented polarization-consistent bases of Jensen (<i>J. Chem. Phys.</i> <b>2002</b>, <i>117</i>, 9234) in providing accurate intermolecular potentials for the benzene–, naphthalene–, and anthracene–argon complexes. The basis sets are extended by addition of midbond functions. As reference we consider CCSD­(T) results obtained with Dunning’s bases. For the benzene complex a systematic basis set study resulted in the selection of the (Z)­Pol-33211 and the aug-pc-1-33321 bases to obtain the intermolecular potential energy surface. The interaction energy values and the shape of the CCSD­(T)/(Z)­Pol-33211 calculated potential are very close to the best available CCSD­(T)/aug-cc-pVTZ-33211 potential with the former basis set being considerably smaller. The corresponding differences for the CCSD­(T)/aug-pc-1-33321 potential are larger. In the case of the naphthalene–argon complex, following a similar study, we selected the (Z)­Pol-3322 and aug-pc-1-333221 bases. The potentials show four symmetric absolute minima with energies of −483.2 cm^–1 for the (Z)­Pol-3322 and −486.7 cm^–1 for the aug-pc-1-333221 basis set. To further check the performance of the selected basis sets, we evaluate intermolecular bound states of the complexes. The differences between calculated vibrational levels using the CCSD­(T)/(Z)­Pol-33211 and CCSD­(T)/aug-cc-pVTZ-33211 benzene–argon potentials are small and for the lowest energy levels do not exceed 0.70 cm^–1. Such differences are substantially larger for the CCSD­(T)/aug-pc-1-33321 calculated potential. For naphthalene–argon, bound state calculations demonstrate that the (Z)­Pol-3322 and aug-pc-1-333221 potentials are of similar quality. The results show that these surfaces differ substantially from the available MP2/aug-cc-pVDZ potential. For the anthracene–argon complex it proved advantageous to calculate interaction energies by using the (Z)­Pol and the aug-pc-1 basis sets, and we expect it to be increasingly so for complexes containing larger aromatic molecules

He–, Ne–, and Ar–Phosgene Intermolecular Potential Energy Surfaces

Using the CCSD­(T) model, we evaluated the intermolecular potential energy surfaces of the He–, Ne–, and Ar–phosgene complexes. We considered a representative number of intermolecular geometries for which we calculated the corresponding interaction energies with the augmented (He complex) and double augmented (Ne and Ar complexes) correlation-consistent polarized valence triple-ζ basis sets extended with a set of 3s3p2d1f1g midbond functions. These basis sets were selected after systematic basis set studies carried out at geometries close to those of the surface minima. The He–, Ne–, and Ar–phosgene surfaces were found to have absolute minima of −72.1, −140.4, and −326.6 cm^–1 at distances between the rare-gas atom and the phosgene center of mass of 3.184, 3.254, and 3.516 Å, respectively. The potentials were further used in the evaluation of rovibrational states and the rotational constants of the complexes, providing valuable results for future experimental investigations. Comparing our results to those previously available for other phosgene complexes, we suggest that the results for Cl₂–phosgene should be revised

He–, Ne–, and Ar–Phosgene Intermolecular Potential Energy Surfaces

Using the CCSD­(T) model, we evaluated the intermolecular potential energy surfaces of the He–, Ne–, and Ar–phosgene complexes. We considered a representative number of intermolecular geometries for which we calculated the corresponding interaction energies with the augmented (He complex) and double augmented (Ne and Ar complexes) correlation-consistent polarized valence triple-ζ basis sets extended with a set of 3s3p2d1f1g midbond functions. These basis sets were selected after systematic basis set studies carried out at geometries close to those of the surface minima. The He–, Ne–, and Ar–phosgene surfaces were found to have absolute minima of −72.1, −140.4, and −326.6 cm^–1 at distances between the rare-gas atom and the phosgene center of mass of 3.184, 3.254, and 3.516 Å, respectively. The potentials were further used in the evaluation of rovibrational states and the rotational constants of the complexes, providing valuable results for future experimental investigations. Comparing our results to those previously available for other phosgene complexes, we suggest that the results for Cl₂–phosgene should be revised

He–, Ne–, and Ar–Phosgene Intermolecular Potential Energy Surfaces

Using the CCSD­(T) model, we evaluated the intermolecular potential energy surfaces of the He–, Ne–, and Ar–phosgene complexes. We considered a representative number of intermolecular geometries for which we calculated the corresponding interaction energies with the augmented (He complex) and double augmented (Ne and Ar complexes) correlation-consistent polarized valence triple-ζ basis sets extended with a set of 3s3p2d1f1g midbond functions. These basis sets were selected after systematic basis set studies carried out at geometries close to those of the surface minima. The He–, Ne–, and Ar–phosgene surfaces were found to have absolute minima of −72.1, −140.4, and −326.6 cm^–1 at distances between the rare-gas atom and the phosgene center of mass of 3.184, 3.254, and 3.516 Å, respectively. The potentials were further used in the evaluation of rovibrational states and the rotational constants of the complexes, providing valuable results for future experimental investigations. Comparing our results to those previously available for other phosgene complexes, we suggest that the results for Cl₂–phosgene should be revised

He–, Ne–, and Ar–Phosgene Intermolecular Potential Energy Surfaces

Using the CCSD­(T) model, we evaluated the intermolecular potential energy surfaces of the He–, Ne–, and Ar–phosgene complexes. We considered a representative number of intermolecular geometries for which we calculated the corresponding interaction energies with the augmented (He complex) and double augmented (Ne and Ar complexes) correlation-consistent polarized valence triple-ζ basis sets extended with a set of 3s3p2d1f1g midbond functions. These basis sets were selected after systematic basis set studies carried out at geometries close to those of the surface minima. The He–, Ne–, and Ar–phosgene surfaces were found to have absolute minima of −72.1, −140.4, and −326.6 cm^–1 at distances between the rare-gas atom and the phosgene center of mass of 3.184, 3.254, and 3.516 Å, respectively. The potentials were further used in the evaluation of rovibrational states and the rotational constants of the complexes, providing valuable results for future experimental investigations. Comparing our results to those previously available for other phosgene complexes, we suggest that the results for Cl₂–phosgene should be revised

He–, Ne–, and Ar–Phosgene Intermolecular Potential Energy Surfaces

Using the CCSD­(T) model, we evaluated the intermolecular potential energy surfaces of the He–, Ne–, and Ar–phosgene complexes. We considered a representative number of intermolecular geometries for which we calculated the corresponding interaction energies with the augmented (He complex) and double augmented (Ne and Ar complexes) correlation-consistent polarized valence triple-ζ basis sets extended with a set of 3s3p2d1f1g midbond functions. These basis sets were selected after systematic basis set studies carried out at geometries close to those of the surface minima. The He–, Ne–, and Ar–phosgene surfaces were found to have absolute minima of −72.1, −140.4, and −326.6 cm^–1 at distances between the rare-gas atom and the phosgene center of mass of 3.184, 3.254, and 3.516 Å, respectively. The potentials were further used in the evaluation of rovibrational states and the rotational constants of the complexes, providing valuable results for future experimental investigations. Comparing our results to those previously available for other phosgene complexes, we suggest that the results for Cl₂–phosgene should be revised

He–, Ne–, and Ar–Phosgene Intermolecular Potential Energy Surfaces

Using the CCSD­(T) model, we evaluated the intermolecular potential energy surfaces of the He–, Ne–, and Ar–phosgene complexes. We considered a representative number of intermolecular geometries for which we calculated the corresponding interaction energies with the augmented (He complex) and double augmented (Ne and Ar complexes) correlation-consistent polarized valence triple-ζ basis sets extended with a set of 3s3p2d1f1g midbond functions. These basis sets were selected after systematic basis set studies carried out at geometries close to those of the surface minima. The He–, Ne–, and Ar–phosgene surfaces were found to have absolute minima of −72.1, −140.4, and −326.6 cm^–1 at distances between the rare-gas atom and the phosgene center of mass of 3.184, 3.254, and 3.516 Å, respectively. The potentials were further used in the evaluation of rovibrational states and the rotational constants of the complexes, providing valuable results for future experimental investigations. Comparing our results to those previously available for other phosgene complexes, we suggest that the results for Cl₂–phosgene should be revised

He–, Ne–, and Ar–Phosgene Intermolecular Potential Energy Surfaces

Using the CCSD­(T) model, we evaluated the intermolecular potential energy surfaces of the He–, Ne–, and Ar–phosgene complexes. We considered a representative number of intermolecular geometries for which we calculated the corresponding interaction energies with the augmented (He complex) and double augmented (Ne and Ar complexes) correlation-consistent polarized valence triple-ζ basis sets extended with a set of 3s3p2d1f1g midbond functions. These basis sets were selected after systematic basis set studies carried out at geometries close to those of the surface minima. The He–, Ne–, and Ar–phosgene surfaces were found to have absolute minima of −72.1, −140.4, and −326.6 cm^–1 at distances between the rare-gas atom and the phosgene center of mass of 3.184, 3.254, and 3.516 Å, respectively. The potentials were further used in the evaluation of rovibrational states and the rotational constants of the complexes, providing valuable results for future experimental investigations. Comparing our results to those previously available for other phosgene complexes, we suggest that the results for Cl₂–phosgene should be revised