Binary-encounter form factor and its use in the calculation of inelastic cross sections involving Rydberg atoms

Gounand, F.; Petitjean, L.

doi:10.1103/physreva.30.61

Cited by 37 publications

(29 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This is an alternative mechanism of collisional quenching of Rydberg states as compared to the standard mechanism of quasielastic or inelastic transitions associated with the scattering of a weakly bound electron by a perturbing atomic or molecular particle (see [40][41][42][43]). The standard mechanism proposed by Fermi [44] for the description of the spectral shift of Rydberg atomic series in a buffer rare gas, has been the subject of intensive research in studies of quasielastic l-mixing [45][46][47] and J-mixing [48] collisions, various types of inelastic transitions between highly excited states [49][50][51][52][53][54][55][56][57][58], and ionization of Rydberg atoms [59,60] in collisions with neutral atomic particles. For collisions of Rydberg atoms with nonpolar and weakly polar molecules the electron-perturber scattering mechanism of ionization as well as quasielastic and inelastic transitions was studied within the framework of different versions of the impulse-approximation approach [61,62,64] based on the quasifree electron model.…”

Section: Introductionmentioning

confidence: 99%

Resonant quenching of Rydberg atomic states by highly polar molecules

Нариц

Mironchuk

Лебедев

2016

J. Phys. B: At. Mol. Opt. Phys.

View full text Add to dashboard Cite

The results of theoretical studies of the resonant quenching and ion-pair formation processes induced by collisions of Rydberg atoms with highly polar molecules possessing small electron affinities are reported. We elaborate an approach for describing collisional dynamics of both processes and demonstrate the predominant role of resonant quenching channel of reaction for the destruction of Rydberg states by electron-attaching molecules. The approach is based on the solution of the coupled differential equations for the transition amplitudes between the ionic and Rydberg covalent terms of a quasimolecule formed during a collision of particles. It takes into account the possibility of the dipole-bound anion decay in the Coulomb field of the positive ionic core and generalizes previous models of charge-transfer processes involving Rydberg atoms to the cases, when the multistate Landau-Zener approaches become inapplicable. Our calculations for ( ) nl Rb atom perturbed by C H SO 2 4 3 , CH CHCN 2 , CH NO 3 2 , CH CN 3 , C H O 3 2 3 , and C H O 3 4 3molecules show that the curves representing the dependence of the resonant quenching cross sections on the principal quantum number n are bell-shaped with the positions of maxima being shifted towards lower values of n and the peak values, ( ) s max q , several times higher than those for the ion-pair formation, ( ) s max i . We obtain a simple power relation between the energy of electron affinity of a molecule and the position of maximum in n-dependence of the resonant quenching cross section. It can be used as an additional means for determining small binding energies of dipole-bound anions from the experimental data on resonant quenching of Rydberg states by highly polar molecules.

show abstract

Section: Introductionmentioning

confidence: 99%

Resonant quenching of Rydberg atomic states by highly polar molecules

Нариц

Mironchuk

Лебедев

2016

J. Phys. B: At. Mol. Opt. Phys.

View full text Add to dashboard Cite

show abstract

“…When calculating the value of Equation 5, the round-off errors (loss in accuracy) quickly start to add up, and once the standard floating-point limit of a machine is reached, fail to provide real, non-infinite values. This has been remarked upon by various authors (e.g., Gounand & Petitjean 1984;Delone et al 1994;Flannery & Vrinceanu 2002) and Dewangan (2012) point out that the exact value of n for which these calculations start to break down depends on the variety of algorithms and methods used. The round-off errors and limitations of the standard floating-point machine representation of numbers have driven other methods of calculation for oscillator strengths.…”

Section: Methods Of Calculationmentioning

confidence: 90%

Exact bound–bound Gaunt factor values for quantum levels up to n = 2000

Morabito

Harten

Salgado

et al. 2014

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

Comparison of observations of radio recombination lines in the interstellar medium with theoretical models can be used to constrain electron temperature and density of the gas. An important component of the models is spontaneous transition rates between bound levels. Calculating these rates relies on accurate bound-bound oscillator strengths, which can be cast in terms of the Gaunt factor. The Gaunt factor contains terminating hypergeometric functions that cannot be calculated with sufficient accuracy for high quantum levels (n 50) by standard machine-precision methods. Methods to overcome the accuracy problem have been developed, which include asymptotic expansions and recursion relations. These methods, used in astrophysical models to calculate oscillator strengths, can introduce errors, sometimes up to as much as ∼ 8 per cent. Detections of radio recombination lines with the new Low Frequency Array (LOFAR) has prompted an examination of theoretical models of the interstellar medium. We revisit the calculation of the Gaunt factor, employing modern arbitraryprecision computational methods to tabulate the Gaunt factor for transitions up to quantum level n = 2000, sufficient to model low frequency Carbon radio recombination lines. The calculations provide a relative error of ∼ 3 × 10 −4 when compared to more detailed calculations including relativistic corrections. Our values for the Gaunt factor are provided for download in a tabular format to be used for a wide range of applications.

show abstract

“…Letter to the Editor where gnl(p) is the radial wavefunction of the Rydberg electron in the momentum space. The validity of this approximation in Rydberg-neutral collisions has been recently investigated by Gounand and Petitjean (1984). It is important to note that in the calculation of the cross section according to equations (1) and (2), AE in the expression for po may be neglected.…”

Section: L167 L168mentioning

confidence: 99%

“…Experiment: $, Na(nd)+He, T = 430 K, Gallagher et a2 (1977); 0, Rb(ns)+ He, T = 520 K, Hugon et al (1980): I, Rb(np) + He, T = 460 K, Gounand et a/ (1977): 0, Na( n s ) + He, T = 425 K, Gallagher and Cooke (1979);4, Rb(ns)+Xe, T = 2 9 6 K , Hugon etal (1982);p, Rb(nd)+Xe, T = 2 9 6 K , Hugon er al (1982); *, Rb(ns)+ He, T = 296 K, Hugon et al (1982). Theory: full curves, equation (4) multiplied by ( n ' -l o ) / n ' with L,,= 1.14, L,,=-5.8; 6,= 1.35, 6,=0.014 for Na, 8, = 3.14 and 3.20 if 5 S n* S 20, 6, = 3.16 and 3.24 if 25 s n* s 45, 6, = 2.65, 6, = 1.40 for Rb; broken curves, Born approximation with a Fermi pseudopotential (Hugon er al 1982) for large n* values and impulse approach(Gounand and Petitjean 1984) for low n* values; dotted curve, scaling formula ofHickman (1981).…”

mentioning

confidence: 99%

Analytical expressions for cross sections of Rydberg-neutral inelastic collisions

Kaulakys¹

1985

J. Phys. B: At. Mol. Phys.

View full text Add to dashboard Cite

We obtain simple analytical expressions for the cross sections of the statechanging and ionisation collisions of Rydberg atoms with neutral atomic particles due to the Rydberg-electron-perturber interaction. The theoretical investigation is based on the impulse approximation .and binary encounter approach for the form factor. The earlier results of Alekseev and Sobel'man and Omont turn out to be the limiting cases of our expressions. The calculated quenching cross sections for the Rydberg states agree well with experimental results and numerical calculations.

show abstract

Binary-encounter form factor and its use in the calculation of inelastic cross sections involving Rydberg atoms

Cited by 37 publications

References 27 publications

Resonant quenching of Rydberg atomic states by highly polar molecules

Resonant quenching of Rydberg atomic states by highly polar molecules

Exact bound–bound Gaunt factor values for quantum levels up to n = 2000

Analytical expressions for cross sections of Rydberg-neutral inelastic collisions

Contact Info

Product

Resources

About