The cross sections of the transverse relaxation of NH3 colliding with various spherical perturbers are measured and examined as a function of molecular parameters, such as ionization energy, polarizability, and mass. The observed cross sections show good correlation with these molecular parameters. An empirical formula in the unit of Angstrom(2), sigma=25.5 (alpha (2)M)(1/6), is obtained, where sigma is the cross section, alpha is the polarizability of the perturber in the unit of Angstrom(3), and M is the reduced mass of the colliding molecules in the unit of g/mol. This expression can be used to evaluate the cross sections of collisions between NH3 and other spherical perturbers.