Editing Rosen and Morse potential

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The '''Rosen and Morse potential''' is given by (Eq. 1 <ref>[http://dx.doi.org/10.1103/PhysRev.42.210 N. Rosen and Philip M. Morse "On the Vibrations of Polyatomic Molecules", Physical Review '''42''' pp. 210-217 (1932)]</ref>):
 
:<math>\Phi(r) = B \tanh (r/d) - C {\mathrm {sech}}^2 (r/d) </math>

the minimum is located at 

:<math>r_{\mathrm {min}} = - \tanh^{-1} (B/2C)  </math>

as long as <math>|B|  \lt 2C</math>.

==References==
<references/>
[[category: models]]