Albert,

The beta0-5 numbers in Lindsay are the values of the spline coefficients for the quintic spline function between 109.5 and 120 degrees.

# The function has the form g(x) = beta0 + beta1*x + beta2*x^2 … beta5*x^5All you have to do in the CH.airebo file is make the appropriate substitution under the comment #g_c1 and g_c2.

The T0 is more difficult. You have to calculate the spline coefficients for a tricubic spline Tij(Nit,Njt,NijConj), then substitute these coefficients in to the CH.airebo where it says #T_ij. This of course is easier said than done. You need a code to calculate the coefficients for the tricubic spline from the node values which is nontrivial. Brenner’s original code has the subroutine to calculate the spline coefficients in it. With some minor modification, you can get it to output the coefficients. See table 5 (Brenner 2002) for an explanation of the values of the T tricubic spline. Also note that Stuart (2000) and Brenner (2002) have slightly different values for the node values of T.

Hope that helps.

Dave