Rosen and Morse potential

The Rosen and Morse potential is given by (Eq. 1 ):

$\Phi (r)=B\tanh(r/d)-C{\mathrm {sech} }^{2}(r/d)$

the minimum is located at

Failed to parse (Conversion error. Server ("https://wikimedia.org/api/rest_") reported: "Cannot get mml. Server problem."): {\displaystyle r_{\mathrm {min} }=-\tanh ^{-1}(B/2C)}

as long as Failed to parse (unknown function "\lt"): {\displaystyle |B| \lt 2C} .