what is meant by distance of closest approach - Physics - Atoms

Question

what is meant by distance of closest approach?

Angel Sobiya Anim · Accepted Answer

Distance of closest approach of 2 objects is the distance
between thier centres when they are extremely tangent The objects
may be geometric shapes or physical particles with well defined
boundaries the distance of closest approach is sometimes referred
to as closest distance For the simple objects ,spheres,the distance
of closest approach is simply the sum of thier radii for non
spherical objects the distance of closest approach is function of
orientation of objects and its calculation can be difficult