2D contour plots of the c-SiC₃ + He van der Waals 3D-PES. Top panels (a) and (b): PES as a function of radial distance (R) and in-plane angle (θ) at a fixed out-of-plane angle (ϕ) of 0 and 90 degrees. Bottom panels (c) and (d): PES as a function of θ and ϕ at a fixed intermolecular distance (R) of 6.74 and 8.31 Bohr. Blue regions indicate attractive interactions (negative potential energy in inverse centimeters), while yellow and red contours represent repulsive interactions (positive potential energy, in inverse centimeters).