Elastic scattering and rotational excitation of nitrogen molecules by sodium atoms

Abstract

Relaxation of energetic S(1D) atoms in Xe gas: Comparison of ab initio calculations with experimental data J. Chem. Phys. 135, 024304 (2011) Ultracold O2 + O2 collisions in a magnetic field: On the role of the potential energy surface J. Chem. Phys. 134, 124310 (2011) Cold and ultracold NH-NH collisions: The field-free case J. Chem. Phys. 134, 124309 (2011) Quantum and classical study of surface characterization by three-dimensional helium atom scattering J. Chem. Phys A quantal study of the rotational excitation of nitrogen molecules by sodium atoms is carried out. We present the two-dimensional potential energy surface of the NaN 2 complex, with the N 2 molecule treated as a rigid rotor. The interaction potential is computed using the spin unrestricted coupledcluster method with single, double, and perturbative triple excitations (UCCSD(T)). The long-range part of the potential is constructed from the dynamic electric dipole polarizabilities of Na and N 2 . The total, differential, and momentum transfer cross sections for rotationally elastic and inelastic transitions are calculated using the close-coupling approach for energies between 5 cm −1 and 1500 cm −1 . The collisional and momentum transfer rate coefficients are calculated for temperatures between 100 K and 300 K, corresponding to the conditions under which Na-N 2 collisions occur in the mesosphere.

Recent Advances in Development and Applications of the Mixed Quantum/Classical Theory for Inelastic Scattering

“…59 Here, again, our MQCT results are tested against the full-quantum CC results of Dalgarno. 20 The dependence is rather complicated, but every quantum oscillation is reproduced by MQCT, even at small scattering angles (forward scattering), where classical approximation is not expected to be accurate. Recall that neither the elastic nor the differential cross section can be reproduced by the classical scattering theory, due to the lack of phase information and quantum interference.…”

“…Differential cross section for elastic scattering of N2(j = 0) + Na at E = 50 cm -1 . Fullquantum results 20 are shown by the green line; our MQCT results, 59 by red line. So, we see that for N2 + Na collisions, MQCT is in detailed agreement with full-quantum calculations.…”

“…This phase is then accounted for simply by multiplying the final computed probability amplitude by the phase factor: . Such corrected probability amplitude can be used to compute the elastic scattering total cross section: (20) and the differential scattering amplitude (needed in calculations of the differential cross section 60 ): (21) where is the Legendre polynomial of th degree. Note that this method can be applied to the inelastic scattering channels as well, but the total inelastic cross sections are insensitive to phases, because probability amplitudes are squared before any other operations in eq…”

“…[16][17][18] Finally, very detailed information about the process may be needed, such as differential over scattering angle cross section for state-to-state transition. 19,20 If several of these complications have to be tackled simultaneously, the inelastic scattering process does not look simple anymore.…”

Mixed quantum/classical calculations of total and differential elastic and rotationally inelastic scattering cross sections for light and heavy reduced masses in a broad range of collision energies

“…Our choice of the benchmark systems was based on the following arguments. First of all, accurate full-quantum coupled-channel (CC) results for these systems are available from recent literature, [11][12][13] as well as potential energy surfaces (PES) used in those studies. Second, all atoms in Na + N 2 are relatively heavy, while they are light in the He + H 2 .…”