====== 1次元W型ポテンシャル ======
{{http://sstweb.ee.ous.ac.jp/seminor/Lesson_MD/L12/Fig/V_W.gif}}
  * ポテンシャル\\ $$
V(x)=E_0\displaystyle\left[
\left(\frac{x}{x_0}\right)^4-
\left(\frac{x}{x_0}\right)^2
\right]
$$
 
  * 力\\ $$
F_x=-\displaystyle\frac{\partial}{\partial x}V(x)
=-\frac{E_0}{x}\displaystyle\left[
4\left(\frac{x}{x_0}\right)^4-
2\left(\frac{x}{x_0}\right)^2
\right]
$$