Atom–surface scattering dynamics at hyperthermal energies

Amirav, Aviv; Cardillo, M. J.; Trevor, P. L.; Lim, Carmay; Tully, John C.

doi:10.1063/1.453192

Cited by 114 publications

(45 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Amirav et al 31 published measured angular distributions for the scattering of Xe on the Ge͑100͒ surface at different incidence angles and different temperatures. At the incidence energy of 2.4 eV and 45°incidence scattering angle, they find an asymmetric double peaked distribution.…”

Section: Scattering Of Xe On Ge(100)mentioning

confidence: 99%

“…11-29͒ and Xe. [30][31][32][33][34][35][36][37] For these, a classical theory of scattering is appropriate. If one neglects the interaction with surface phonons and one assumes that the scattering potential in the horizontal direction is a single cosine or sine term, then theory predicts that the angular distribution will be symmetrically displaced about the specular scattering angle.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Classical theory for asymmetric in-plane atom surface scattering

2009

View full text Add to dashboard Cite

In-plane atom surface scattering perturbation theory within a generalized Langevin equation formalism is proposed to account for the asymmetry found in angular distributions of heavy rare gas atoms scattered by corrugated surfaces. We show that when the surface corrugation is represented in terms of the first two ͑sine͒ Fourier components, one finds an asymmetric angular distribution. This asymmetry reflects the ratchetlike form of the effective corrugation. Adding in higher-order terms can also increase the number of rainbow scattering angles. Three rainbows are found for a second-order sine term in the corrugation, four symmetrically spaced rainbow angles are found when adding in a second-order cosine term to the corrugation. Analytic expressions for the angular distribution are derived in terms of a Morse oscillator model. The theory accounts well for the asymmetry and predicts its disappearance as the incident scattering angle is increased. It also features a decrease in the distance between the rainbow angles as the angle of incidence is increased and as the incident energy is increased. The theory is successfully applied to the experimental results of Kondo et al. ͓Eur. Phys. J. D 38, 129 ͑2006͔͒ for the scattering of Ar on LiF͑100͒ and the results of Amirav et al. ͓J. Chem. Phys. 87, 1796 ͑1987͔͒ for the scattering of Xe on Ge͑100͒ and Ar and Kr on Ag͑100͒.

show abstract

Section: Scattering Of Xe On Ge(100)mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Classical theory for asymmetric in-plane atom surface scattering

2009

View full text Add to dashboard Cite

show abstract

“…spheres. 6,11 This leads to an increase in the energy of the scattered atoms with increasing scattering angle, opposite to the hard cubes behavior.…”

Section: Introductionmentioning

confidence: 81%

“…These include Xe-Ni͑111͒, 3 Xe-Pt͑111͒, 4,5 Xe-GaAs͑100͒, 6 Xe-Ag͑100͒, 6 Xe-Ge͑100͒, 6 Ar-Pt͑111͒, 5 Ar-Ag͑111͒, 7 and Ar-Ru͑0001͒. 8 For incident energies greater than about 1 eV, the angular distribution of the scattered flux is concentrated in one peak whose intensity maximum is at the specular or larger angle.…”

Section: Introductionmentioning

confidence: 97%

Hyperthermal Ar atom scattering from a C(0001) surface

Gibson

Sibener

Upadhyaya

et al. 2008

The Journal of Chemical Physics

View full text Add to dashboard Cite

Experiments and simulations on the scattering of hyperthermal Ar from a C(0001) surface have been conducted. Measurements of the energy and angular distributions of the scattered Ar flux were made over a range of incident angles, incident energies (2.8-14.1 eV), and surface temperatures (150-700 K). In all cases, the scattering is concentrated in a narrow superspecular peak, with significant energy exchange with the surface. The simulations closely reproduce the experimental observations. Unlike recent experiments on hyperthermal Xe scattering from graphite [Watanabe et al., Eur. Phys. J. D 38, 103 (2006)], the angular dependence of the energy loss is not approximated by the hard cubes model. The simulations are used to investigate why parallel momentum conservation describes Xe scattering, but not Ar scattering, from the surface of graphite. These studies extend our knowledge of gas-surface collisional energy transfer in the hyperthermal regime, and also demonstrate the importance of performing realistic numerical simulations for modeling such encounters.

show abstract

“…The H atom photodesorption probabilities are larger than those for D in the H 2 O and D 2 O amorphous ice systems ( 39,40 states that the energy transfer from the X atom to a water molecule (which is assumed to be stationary initially) is dependent on the mass ratio of the two colliding objects, as follows:…”

Section: A X(=hd) Atom Photodesorptionmentioning

confidence: 99%

Isotope effects on the photodesorption processes of X2O (X = H,D) and HOD ice

Koning

Kroes

Arasa

2013

The Journal of Chemical Physics

View full text Add to dashboard Cite

To investigate the isotope effects on the photodesorption processes of X 2 O (X = H,D) ice, molecular dynamics calculations have been performed on the ultraviolet photodissociation of an H 2 O or a D 2 O molecule in an H 2 O or a D 2 O amorphous ice surface, and on HOD photodissociation in an H 2 O amorphous ice surface, where the photodissociated molecules were located in the top four or five monolayers at ice temperatures of 10, 20, 30, 60, and 90 K. Three photodesorption processes can occur upon X 2 O photodissociation: X atom photodesorption, OX radical photodesorption, and X 2 O (or HOD) molecule photodesorption. X 2 O (or HOD) photodesorption can occur after recombination of X and OX, or after an energetic X atom photofragment kicks a surrounding X 2 O molecule from the ice surface. Isotope effects are observed for the X atom and the OX radical photodesorption as well as for the kick-out photodesorption. However, no isotope effects were noticeable for the photodesorption of recombined X 2 O molecules. The average D atom photodesorption probabilities are about a factor 0.9 smaller than those for the H atom, regardless of the isotope of the surrounding ice system. Also, the kick-out mechanism is more likely to occur if a D photofragment is created upon dissociation than if an H atom is created. These observations can be explained by more efficient energy transfer from the D atom to water molecules than from the H atom. Reasoning based on the X 2 O phonon frequencies associated with the librational modes and energy transfer efficiencies explain why the OX radical photodesorption probabilities are noticeably larger if the OX radical desorbs from a D 2 O ice system than from an H 2 O ice system. Also, the OX radical photodesorption is more probable upon dissociation of DOX (X = H,D) than upon dissociation of HOX (X = H,D), because the initial kinetic energy of the OX radical is larger if the dissociation products are D + OX than H + OX. The branching ratio of OD OH desorption following photodissociation of an HOD molecule in ice (about 1.0) is much lower than the OD OH branching ratio in gas-phase HOD photodissociation. This may lead to differences in isotope fractionation in OH(g) formation in dense and diffuse clouds in the interstellar medium.

show abstract

Atom–surface scattering dynamics at hyperthermal energies

Cited by 114 publications

References 12 publications

Classical theory for asymmetric in-plane atom surface scattering

Classical theory for asymmetric in-plane atom surface scattering

Hyperthermal Ar atom scattering from a C(0001) surface

Isotope effects on the photodesorption processes of X2O (X = H,D) and HOD ice

Contact Info

Product

Resources

About