(Subscript[ϵ, 0]) =  8.85419*^-12

(Subscript[N, A]) =  6.02205*^23

(Subscript[RAM, Na]) =  22.9898(Subscript[RAM, Cl]) = 34.9688

e  =  1.60219*^-19

(Subscript[r, 0]) =  2.5*^-10

(Subscript[m, Na]) =  ((Subscript[RAM, Na])/((10^3) (Subscript[N, A])))(Subscript[m, Cl]) =  ((Subscript[RAM, Cl])/((10^3) (Subscript[N, A])))

(Subscript[F, mm])[r_]  = 
      -((e^2)/(4 π (Subscript[ϵ, 0 ]) (r^2)))

(Subscript[F, pm])[r_]  = 
      ((e^2)/(4 π (Subscript[ϵ, 0]))) 
        ((1/(r^2)) - (((((Subscript[r, 0])))^8)/(r^10)))

T = 1.2*^-12

(Subscript[x1, 0]) = -5.5 (Subscript[r, 0])(Subscript[x2, 0]) =  0.0(Subscript[x3, 0]) =  1.1  (Subscript[r, 0])(Subscript[v1, 0]) =  5000.0(Subscript[v2, 0]) =  0.0(Subscript[v3, 0]) =  0.0

\(\(xrules = 
      NDSolve[{
			
          \(\(x1'\)'\)[t] == 
            \(F\_pm[x2[t] - x1[t]]\  + \ F\_mm[x3[t] - x1[t]]\)\/m\_Cl, 

          			\(\(x2'\)'\)[t] == 
            \(\ \(-F\_pm[x2[t] - x1[t]]\)\  + \ F\_pm[x3[t] - x2[t]]\)\/m
                \_Na, 
			
          \(\(x3'\)'\)[t] == 
            \(\(-F\_mm[x3[t] - x1[t]]\)\  - \ F\_pm[x3[t] - x2[t]]\)\/m\_Cl, 
          
			x1[0] == x1\_0, x2[0] == x2\_0, x3[0] == x3\_0, 
			
          \(x1'\)[0] == v1\_0, \(x2'\)[0] == v2\_0, \(x3'\)[0] == v3\_0}, 

        		{x1, x2, x3}, {t, 0, T}, MaxSteps -> 2000]; \)\)

pos1[t_]  :=  (x1[t] /. xrules)[[1]]pos2[t_]  :=  (x2[t] /. xrules)[[1]]pos3[t_]  :=  (x3[t] /. xrules)[[1]]vel1[t_]  :=  (x1'[t] /. xrules)[[1]]vel2[t_]  :=  (x2'[t] /. xrules)[[1]]vel3[t_]  :=  (x3'[t] /. xrules)[[1]]

pos1[0.5  T]vel3[0.3  T]

\(threeIonFrame[t_]\  := 
      Show[Graphics[{AbsolutePointSize[15], 

            				{RGBColor[0.8, 0.8, 0], Point[{pos1[t], 0}]}, {
              RGBColor[0.4, 0.4, 0.4], Point[{pos2[t], 0}]}, {
              RGBColor[0.8, 0.8, 0], Point[{pos3[t], 0}]}}], 
		
        PlotRange -> {{\(-15\) r\_0, 15  r\_0}, Automatic}]\)

Table[threeIonFrame[t], {t, 0, T, T/100}];