Move the cursor into the plotter window and at the gnuplot> prompt enter the following commands, finish each line with an enter. Read the rest of this page before you continue.

a=0.0397

(Line 1 : defines the quantity a and assigns it the value of 0.0397)

b=17e3

(Line 2 : defines the quantity b and assigns it the value of 17154 kJ)

d=138e12

(Line 3 : defines the quantity d and assigns it the value of 138 x 10¹²)

repulsion(R)=b*exp(-a*R)

(Line 4 : defines the function, repulsion(R), as a function of R)

attraction(R)=-d/R**6

(Line 5 : defines the function, attraction(R), as a function of R)

pe(R)=repulsion(R)+attraction(R)

(Line 6 : defines the function, pe(R), as a function of R)