Wrong scaling factor in Tanh profile

Expressions for tanh profile and the corresponding reflective damping factors are taken from

Bahr, Press, et al, Phys. Rev. B, vol. 47 (8), p. 4385 (1993)

But the problem is that rms widths of the transition region are different in models given there!

For erf model rms=sigma, for tanh model rms>sigma (rms~1.14*sigma).

At z=0 these two profiles have same derivative value but tanh has longer tails.

Solution: factor sqrt(2/pi) in tanh profile should be replaced with pi/(2 sqrt(3)) and reflective factors should be updated correspondingly.

Picture from the mentioned paper: