Additional flexibility is gained via the analytic approach as formulas for the distance to minimum energy from the pore center r m , the point of zero potential r o and the well minimum energy o are all obtained for the outer layer. Unfortunately, these expressions involve the undetermined parameters δ 1 and δ 2 . However, we can reason as to how to best estimate these. It seems logical that the minimum total angle required to obtain the correct contribution from the repulsive term, i.e. 2δ 1 , would be smaller than that of the attractive term, 2δ 2 , as the repulsive term is influential over a shorter range than the attractive. For example, in the case studied here, around 7 o as compared with 10 o . Further, we note that from the values obtained in this work δ 2 /δ 1 ≈ 3/2. These angle values, and/or the three halves ratio, could serve as a standard guide for estimating δ 1 and δ 2 when using Eq. ( ) to model gaseous behavior within any (n, n) carbon nanotube. However, more comparison with experimental or simulation results are required before conclusions can be established.