Module oen_robinson 

Oen-Robinson local (impact-parameter dependent) electronic energy loss.

O. S. Oen and M. T. Robinson, Nucl. Instrum. Methods 132, 647 (1976).

The nonlocal part is Lindhard-Scharff with the same k_L. The local model assigns a collision with closest approach r_min the loss

ΔE_e(E, r_min) = S_LS(E) · c² / (2π a²) · exp(-c r_min / a), c = 0.3,

with a the Firsov screening length 0.8853 a0 (Z1^(1/2) + Z2^(1/2))^(-2/3). The prefactor normalises ∫ ΔE_e 2π p dp = S_LS when r_min is identified with the impact parameter p; that identification is the approximation made in the original paper, so the impact-averaged stopping equals the LS value.

The constants c = 0.3 and the choice of length were entered from the literature as remembered by the contributor and have not been verified against the 1976 paper; see docs/data-provenance.md and OR_CONSTANTS_UNVERIFIED. A secondary source, J. F. Ziegler, J. P. Biersack, M. D. Ziegler, SRIM: The Stopping and Range of Ions in Matter (SRIM Co., 2015), Eq. 7-45, p. 7-17, prints ΔE = 0.045 k √E / (π a²) exp(-0.3 r0 / a), which confirms c = 0.3 and the prefactor c² / (2π), but not which screening length a is.

Structs

OenRobinson

Oen-Robinson model. stopping is the impact-averaged value; use OenRobinson::local_loss for the per-collision loss.

Constants

OR_CONSTANTS_UNVERIFIED

Whether the constants of the local model (OR_EXPONENT_COEFFICIENT and the length of local_length) are still not verified against Oen and Robinson, Nucl. Instrum. Methods 132, 647 (1976). true while the Oen-Robinson row of docs/data-provenance.md says “not verified”.

OR_EXPONENT_COEFFICIENT

Exponent coefficient c in exp(-c r_min / a).

Functions

local_length

Firsov-type screening length used by the local model, m.