Interactions between open-shell diatoms: building potential
energy surfaces, bound states and collision dynamics
Marta I. Hernández(a), Massimiliano Bartolomei(a), Estela Carmona-Novillo(a) ,
Jesús Pérez-Ríos(a), José Campos-Martínez(a), Ramón Hernández-Lamoneda(b)
(a)
(b)
Departamento de Física Atómica, Molecular y de Agregados, Instituto de
Física Fundamental, CSIC, c/ Serrano 123, 28006 Madrid, Spain.
Centro de Investigaciones Químicas, Universidad Autónoma del Estado de Morelos,
Cuernavaca, 62210, Mor. ,Mexico.
Interactions between two 3 diatomics give rise to three different intermolecular
potentials of singlet, triplet and quintet multiplicities that might exhibit different
properties. While accurate calculations of potential energy surfaces (PES) are
possible for the quintet multiplicity (since a single reference wave function is
valid), calculations of the other two multiplicities are very challenging as
methods based in multiconfigurational reference wave functions are
unavoidable. This is the case of the O2( 3g-)-O2( 3g-) dimer, of interest in
atmospheric chemistry and physics, condensed phases, and, more recently, in
low and ultralow temperature physics.
We will report on recent theoretical progress of the oxygen dimer. A full rigid
rotor PES for the quintet state has been obtained at the CCSD(T) level of
theory1. The singlet and triplet PESs are obtained by combining the CCSD(T)
quintet potential with multiconfigurational calculations of the singlet-quintet and
triplet-quintet splittings2. In addition, the PESs are extrapolated at long range
using accurate ab initio dispersion coefficients3. Also, the validity of the rigid
rotor approximation has been recently tested by means of analyses of the
dependence of the interaction with the intramolecular vibrational coordinates4.
The new PESs are compared and checked against a variety of experiments.
We have performed calculations of the rovibrational bound states and
compared against spectroscopic observations involving the singlet and triplet
states. In addition, we have carried out accurate close-coupling calculations5 in
order to compare with scattering and rotational energy-transfer experiments,
which are also sensitive to the hard wall and long range behavior of the PESs.
1
M. Bartolomei, E. Carmona-Novillo, M. I. Hernández, J. Campos-Martínez, R.
Hernández-Lamoneda, J. Chem. Phys. 128, 214304 (2008).
2
M. Bartolomei, M. I. Hernández, J. Campos-Martínez, E. Carmona-Novillo, R.
Hernández-Lamoneda, Phys. Chem. Chem. Phys. 10, 5374 (2008)
3
M. Bartolomei, E. Carmona-Novillo, M. I. Hernández, J. Campos-Martínez, R.
Hernández-Lamoneda, submitted to Phys. Chem. Chem. Phys., (2009).
4
E. Carmona-Novillo, M. Bartolomei, J. Pérez-Ríos, J. Campos-Martínez, R.
Hernández-Lamoneda, M. I. Hernández, Int. J. Q. Chem., to be submitted.
5
J. Pérez-Ríos, M. Bartolomei, R. Hernández-Lamoneda, J. Campos-Martínez, M. I.
Hernández, submitted to J. Phys. Chem. A, (2009)