Polar coordinate (R, theta) representation is proposed for the plot of H-b(r(c)) versus ((h) over bar (2)/8m)del(2) rho(b)(r(c)) in AIM analysis to classify, evaluate, and understand weak to strong interactions in a unified way and in more detail; H-b(r(c)) and del(2)rho(b)(r(c)) are total electron energy densities and the Laplacian of rho(b)(r(c))) at bond critical points (BCPs: r(c)), respectively, where rho(b)(r(c)) are electron densities at rc. Both the x- and y-axes of the plot are expressed in the common unit of energy since H-b(r(c)) = G(b)(r(c)) + V-b(r(c)) and ((h) over bar (2)/8m)del(2) rho(b)(r(c)) = H-b(r(c)) - V-b(r(c))/2 (= Gb(r(c)) + V-b(r(c))/2), where G(b)(r(c)) and V-b(r(c)) are kinetic energy densities and potential energy densities, respectively. Data employed for the plot are calculated at BCPs for full-optimized structures and optimized Structures with the fixed distances (r) of r = r(o) + wa(o), where r(o) are the full-optimized distances, a(o) is the Bohr radius, and w = +/- 0.1 and +/- 0.2. The plot draws a helical stream starting from near origin (H-b(r(c)) = ((h) over bar (2)/8m)del(2)rho(b)(r(c)) = 0) for very weak interactions and turns to the right as interactions become stronger. The helical stream is well described by the polar coordinate representation with (R, theta); R is given in the energy unit, and 0 in degrees is measured from the y-axis. The ratio of V-b(r(c))/G(b)(r(c)) (= k) controls theta, of which ail acceptable range in the plot is 45.0 < theta < 206.6 degrees. Each plot for ail interaction gives a Curve, which Supplies important information. It is expressed by theta(p) and kappa(p);theta(p) corresponds to the tangent line measured from the v-direction, and kappa(p) is the curvature of the plot at w = 0. The polar coordinate (R, theta) representation with (theta(p), kappa(p)) helps us to classify, evaluate, and understand the nature of weak to strong interactions in a unified way.