function [X] = v2exact_scalar(r, theta, beta, a)
% Exact expression for the two-jump interaction potential when r1 = r2:
%   function [X] = v2exact(r, theta, beta, a).
% All arguments must be scalars; the return value is a scalar.
%
% Formula:
%
%            2
%  2 a    -r  / 2 beta (1 - sin^2(theta/2))
% -----  e
%   r
%
%

	X = 2 * a / r * exp(-r^2/2/beta * (1-sin(theta/2)^2));
end
