nx cos(theta)*cos(phi) "Director, x-component"
ny sin(theta)*cos(phi) "Director, y-component"
nz sin(phi) "Director, z-component"
dnxx d(nx,x) "Director, x-derivative of x-component"
dnxy d(nx,y) "Director, y-derivative of x-component"
dnxz 0 "Director, z-derivative of x-component"
dnyx d(ny,x) "Director, x-derivative of y-component"
dnyy d(ny,y) "Director, y-derivative of y-component"
dnyz 0 "Director, z-derivative of y-component"
dnzx d(nz,x) "Director, x-derivative of z-component"
dnzy d(nz,y) "Director, y-derivative of z-component"
dnzz 0 "Director, z-derivative of z-component"
F1 0.5*K_11*(dnxx+dnyy+dnzz)^2 "Free energy density, splay"
F2 0.5*K_22*(nx*(dnzy-dnyz)+ny*(dnxz-dnzx)+nz*(dnyx-dnxy))^2 "Free energy density, twist"
F3 0.5*K_33*((ny*(dnyx-dnxy)-nz*(dnxz-dnzx))^2+(nz*(dnzy-dnyz)-nx*(dnyx-dnxy))^2+(nx*(dnxz-dnzx)-ny*(dnzy-dnyz))^2) "Free energy density, bend"
F F1+F2+F3 "Free energy density"