Rotational compound state resonances for an argon and methane scattering system

Smith, Lauren; Malik, David J.; Secrest, Don

doi:10.1063/1.438203

Cited by 90 publications

(36 citation statements)

References 42 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As one can see, the cross sections present several resonances (shape and Feshbach), particularly at low kinetic energies. This typical behavior for cross sections was pointed out by different studies (Smith et al 1979;Christoffel & Bowman 1983;Hammami et al 2008a,b,c;Nkem et al 2009). These resonances are precisely detected in our calculated cross sections.…”

Section: Cross Sectionssupporting

confidence: 63%

Induced rotational excitation of the fluoromethylidynium¹²CF⁺and¹³CF⁺through collision with helium

Ajili

Hammami

2013

A&A

View full text Add to dashboard Cite

Aims. The present paper focuses on the calculation of the collision rate coefficients for rotational excitation of the 12 CF + and its isotopologue 13 CF + by He for temperature ranging from 10 to 300 K. Methods. A two-dimentional (2D) potential energy surface (PES) of the CF + (X 1 Σ + )-He( 1 S) system is calculated at the ab initio coupled cluster with single, double, and perturbative triple excitation level of theory with the aug-cc-pV5Z basis set. The basis set superposition errors were taken into account in our computation. Dynamical calculations of state-to-state rotational integral cross sections of the CF + by collision with He were performed using the close-coupling method. Results. The PES presents a global minimum of ∼212 cm −1 below the CF + -He dissociation limit. Collisional cross sections among the first 11 rotational levels of CF + were calculated for total energies up to 1500 cm −1 . Downward rate coefficients between the rotational levels were calculated for temperature ranging from 10 to 300 K. A propensity toward an even parity of ∆J is observed.

show abstract

Section: Cross Sectionssupporting

confidence: 63%

Induced rotational excitation of the fluoromethylidynium¹²CF⁺and¹³CF⁺through collision with helium

Ajili

Hammami

2013

A&A

View full text Add to dashboard Cite

show abstract

“…Noticeable resonances appear at low collisional energies. This is related to the presence of an attractive potential well, which allows for O 2 -H 2 bound and quasi-bound states to be formed before the complex dissociates (Smith et al 1979;Christoffel & Bowman 1983).…”

Section: Cross Sectionsmentioning

confidence: 99%

Collisional excitation of O₂by H₂: the validity of LTE models in interpreting O₂observations

Lique

Kalugina

Chefdeville

et al. 2014

A&A

View full text Add to dashboard Cite

Context. Oxygen molecules (O 2 ) are of particular interest because of their crucial role in astrochemisty. Modelling of O 2 molecular emission spectra from interstellar clouds requires the calculation of rate coefficients for excitation by collisions with the most abundant species. Aims. Rotational excitation of O 2 (X 3 Σ − ) by H 2 is investigated theoretically and experimentally and we check the validity of the local thermodynamic equilibrium (LTE) approach for interpreting O 2 observations. Methods. Using a new ab initio potential energy surface, collisional excitation of O 2 is studied using a full close-coupling approach. The theoretical calculations are validated by comparison with crossed beam scattering experiments. We also performed calculations for the excitation of O 2 from a large velocity gradient (LVG) radiative transfer code using the new rate coefficients. Results. State-to-state rate coefficients between the 27 lowest levels of O 2 were calculated for temperatures ranging from 5 K to 150 K. The critical densities of the O 2 lines are found to be at > ∼ 10 4 cm −3 for temperatures higher than 50 K. This value is slightly larger than the one previously determined using previous He rate coefficients. Conclusions. The new rate coefficients will help in interpreting O 2 emission lines observed where LTE conditions are not fully fulfilled and enable an accurate determination of the O 2 abundance in the interstellar medium.

show abstract

“…The quasibound states may arise from the tunneling from the centrifugal barrier and from excitation of N 2 to an asymptotically closed channel where N 2 becomes temporarily trapped in one of the bound states of the potential well. [21][22][23] Compared to the depth of the potential well, the energy spacing of the N 2 rotational structure is small, so that both types of quasibound states occur in the same energy range. The disappearance of the resonances as a function of the collision energy can be qualitatively understood by examining the radial functions V λ (R): the spherical term V 0 , which governs the elastic transitions, has a potential well of about 25.2 cm −1 positioned at R = 10.50 a.u., close to the equilibrium distance of the van der Waals complex.…”

Section: Cross Sectionsmentioning

confidence: 99%

Elastic scattering and rotational excitation of nitrogen molecules by sodium atoms

Loreau

Zhang

Dalgarno

2011

The Journal of Chemical Physics

View full text Add to dashboard Cite

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.

show abstract

Rotational compound state resonances for an argon and methane scattering system

Cited by 90 publications

References 42 publications

Induced rotational excitation of the fluoromethylidynium¹²CF⁺and¹³CF⁺through collision with helium

Induced rotational excitation of the fluoromethylidynium¹²CF⁺and¹³CF⁺through collision with helium

Collisional excitation of O₂by H₂: the validity of LTE models in interpreting O₂observations

Elastic scattering and rotational excitation of nitrogen molecules by sodium atoms

Contact Info

Product

Resources

About

Rotational compound state resonances for an argon and methane scattering system

Cited by 90 publications

References 42 publications

Induced rotational excitation of the fluoromethylidynium12CF+and13CF+through collision with helium

Induced rotational excitation of the fluoromethylidynium12CF+and13CF+through collision with helium

Collisional excitation of O2by H2: the validity of LTE models in interpreting O2observations

Elastic scattering and rotational excitation of nitrogen molecules by sodium atoms

Contact Info

Product

Resources

About

Induced rotational excitation of the fluoromethylidynium¹²CF⁺and¹³CF⁺through collision with helium

Induced rotational excitation of the fluoromethylidynium¹²CF⁺and¹³CF⁺through collision with helium

Collisional excitation of O₂by H₂: the validity of LTE models in interpreting O₂observations