27 research outputs found
Sobre la ocurrencia del cretƔceo superior marino en Coihaique , Provincia de AisƩn
Using
the CCSDĀ(T) model, we evaluated the intermolecular potential
energy surfaces of the Heā, Neā, and Arāphosgene
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-Ī¶ 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 Heā, Neā,
and Arāphosgene surfaces were found to have absolute minima
of ā72.1, ā140.4, and ā326.6 cm<sup>ā1</sup> at distances between the rare-gas atom and the phosgene center of
mass of 3.184, 3.254, and 3.516 Ć
, 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 Cl<sub>2</sub>āphosgene should be revised
Ab Initio Ground- and Excited-State Intermolecular Potential Energy Surfaces for the NOāNe and NOāAr van der Waals Complexes
The ground- [NOĀ(X<sup>2</sup>Ī )] and excited-state
[NOĀ(A<sup>2</sup>Ī£<sup>+</sup>)] intermolecular potential energy
surfaces
(IPESs) of the NOāNe and NOāAr van der Waals complexes
are evaluated using the RCCSDĀ(T) spin-restricted coupled cluster method
and d-aug-cc-pVQZ basis set extended with a set of 3<i>s</i>3<i>p</i>2<i>d</i>1<i>f</i>1<i>g</i> midbond functions. These bases are selected from the results
of a systematic basis-set convergence study carried out for the NOĀ(A<sup>2</sup>Ī£<sup>+</sup>)āAr state. We fit the interaction
energies to analytic functions and compare the results to those previously
available. The NOāAr (NOāNe) IPESs are characterized
by absolute minima of ā120 and ā75 cm<sup>ā1</sup> (ā58 and ā5 cm<sup>ā1</sup>) at the ground
and first excited state, respectively, located close to the T-shaped
geometries for the ground states and at linear dispositions in the
case of the excited states. The potentials are further used in the
evaluation of the rovibrational spectra of the complexes, and the
results are compared to those available in the literature
Small and Efficient Basis Sets for the Evaluation of Accurate Interaction Energies: Aromatic MoleculeāArgon Ground-State Intermolecular Potentials and Rovibrational States
By
evaluating a representative set of CCSDĀ(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 benzeneā, naphthaleneā,
and anthraceneāargon complexes. The basis sets are extended
by addition of midbond functions. As reference we consider CCSDĀ(T)
results obtained with Dunningās bases. For the benzene complex
a systematic basis set study resulted in the selection of the (Z)ĀPol-33211
and the aug-pc-1-33321 bases to obtain the intermolecular potential
energy surface. The interaction energy values and the shape of the
CCSDĀ(T)/(Z)ĀPol-33211 calculated potential are very close to the best
available CCSDĀ(T)/aug-cc-pVTZ-33211 potential with the former basis
set being considerably smaller. The corresponding differences for
the CCSDĀ(T)/aug-pc-1-33321 potential are larger. In the case of the
naphthaleneāargon complex, following a similar study, we selected
the (Z)ĀPol-3322 and aug-pc-1-333221 bases. The potentials show four
symmetric absolute minima with energies of ā483.2 cm<sup>ā1</sup> for the (Z)ĀPol-3322 and ā486.7 cm<sup>ā1</sup> 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 CCSDĀ(T)/(Z)ĀPol-33211 and CCSDĀ(T)/aug-cc-pVTZ-33211 benzeneāargon
potentials are small and for the lowest energy levels do not exceed
0.70 cm<sup>ā1</sup>. Such differences are substantially larger
for the CCSDĀ(T)/aug-pc-1-33321 calculated potential. For naphthaleneāargon,
bound state calculations demonstrate that the (Z)ĀPol-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 anthraceneāargon complex it proved advantageous to
calculate interaction energies by using the (Z)ĀPol and the aug-pc-1
basis sets, and we expect it to be increasingly so for complexes containing
larger aromatic molecules
Heā, Neā, and ArāPhosgene Intermolecular Potential Energy Surfaces
Using
the CCSDĀ(T) model, we evaluated the intermolecular potential
energy surfaces of the Heā, Neā, and Arāphosgene
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-Ī¶ 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 Heā, Neā,
and Arāphosgene surfaces were found to have absolute minima
of ā72.1, ā140.4, and ā326.6 cm<sup>ā1</sup> at distances between the rare-gas atom and the phosgene center of
mass of 3.184, 3.254, and 3.516 Ć
, 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 Cl<sub>2</sub>āphosgene should be revised
Heā, Neā, and ArāPhosgene Intermolecular Potential Energy Surfaces
Using
the CCSDĀ(T) model, we evaluated the intermolecular potential
energy surfaces of the Heā, Neā, and Arāphosgene
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-Ī¶ 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 Heā, Neā,
and Arāphosgene surfaces were found to have absolute minima
of ā72.1, ā140.4, and ā326.6 cm<sup>ā1</sup> at distances between the rare-gas atom and the phosgene center of
mass of 3.184, 3.254, and 3.516 Ć
, 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 Cl<sub>2</sub>āphosgene should be revised
Heā, Neā, and ArāPhosgene Intermolecular Potential Energy Surfaces
Using
the CCSDĀ(T) model, we evaluated the intermolecular potential
energy surfaces of the Heā, Neā, and Arāphosgene
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-Ī¶ 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 Heā, Neā,
and Arāphosgene surfaces were found to have absolute minima
of ā72.1, ā140.4, and ā326.6 cm<sup>ā1</sup> at distances between the rare-gas atom and the phosgene center of
mass of 3.184, 3.254, and 3.516 Ć
, 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 Cl<sub>2</sub>āphosgene should be revised
Heā, Neā, and ArāPhosgene Intermolecular Potential Energy Surfaces
Using
the CCSDĀ(T) model, we evaluated the intermolecular potential
energy surfaces of the Heā, Neā, and Arāphosgene
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-Ī¶ 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 Heā, Neā,
and Arāphosgene surfaces were found to have absolute minima
of ā72.1, ā140.4, and ā326.6 cm<sup>ā1</sup> at distances between the rare-gas atom and the phosgene center of
mass of 3.184, 3.254, and 3.516 Ć
, 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 Cl<sub>2</sub>āphosgene should be revised
Heā, Neā, and ArāPhosgene Intermolecular Potential Energy Surfaces
Using
the CCSDĀ(T) model, we evaluated the intermolecular potential
energy surfaces of the Heā, Neā, and Arāphosgene
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-Ī¶ 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 Heā, Neā,
and Arāphosgene surfaces were found to have absolute minima
of ā72.1, ā140.4, and ā326.6 cm<sup>ā1</sup> at distances between the rare-gas atom and the phosgene center of
mass of 3.184, 3.254, and 3.516 Ć
, 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 Cl<sub>2</sub>āphosgene should be revised
Heā, Neā, and ArāPhosgene Intermolecular Potential Energy Surfaces
Using
the CCSDĀ(T) model, we evaluated the intermolecular potential
energy surfaces of the Heā, Neā, and Arāphosgene
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-Ī¶ 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 Heā, Neā,
and Arāphosgene surfaces were found to have absolute minima
of ā72.1, ā140.4, and ā326.6 cm<sup>ā1</sup> at distances between the rare-gas atom and the phosgene center of
mass of 3.184, 3.254, and 3.516 Ć
, 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 Cl<sub>2</sub>āphosgene should be revised
Heā, Neā, and ArāPhosgene Intermolecular Potential Energy Surfaces
Using
the CCSDĀ(T) model, we evaluated the intermolecular potential
energy surfaces of the Heā, Neā, and Arāphosgene
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-Ī¶ 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 Heā, Neā,
and Arāphosgene surfaces were found to have absolute minima
of ā72.1, ā140.4, and ā326.6 cm<sup>ā1</sup> at distances between the rare-gas atom and the phosgene center of
mass of 3.184, 3.254, and 3.516 Ć
, 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 Cl<sub>2</sub>āphosgene should be revised