QBASIC programs listed in the site are:
THREEJ.BAS, which calculates values of 3j symbols. Use described in Section 3.1.1.
REDMAT.BAS, which is used to determine J-basis reduced matrix elements of the tensor operators from LS-basis reduced matrix elements. The use of this program is described in Section 3.1.1.
ENGYLVL.BAS, which is used to calculate energy levels and eigenfunctions from crystal field parameters. This program is discussed at length in Chapter 3. A specific example of its use is given in Section 3.1.3.
ENGYFIT.BAS, which is used to fit crystal field parameters. This program is discussed at length in Chapter 3. A specific example of its use is given in Section 3.2.
CORFACW.BAS determines combined coordination factors (Wybourne normalization). An example of the use of this program is given in Section 5.3.2. CORFACS.BAS is the same program, apart from using Stevens normalization.
INTRTOCF.BAS and CFTOINTR.BAS are superposition model programs described in Chapter 5 of the book.
The Mathematica program LLWDIAG.MA, is described in Section A3.4.
Section A2.3 of the Crystal Field Handbook describes the format of data files, denoted *.DAT and *.WDT, which are used as inputs to, and appear in outputs of, the programs listed above.
It would be best to download a zip file nnprogs.zip containing all the files.
Individual files:
Readme.txt (The description on this page)
Cftointr.bas
Corfacs.bas
Corfacw.bas
Engyfit.bas
Engylvl.bas
Intrtocf.bas
Redmat.bas
Threej.bas
C_luaso4.dat
C_lupo4.dat
C_luvo4.dat
C_scaso4.dat
C_scpo4.dat
C_scvo4.dat
C_yag.dat
C_yaso4.dat
C_ygg.dat
C_ypo4.dat
C_yvo4.dat
Ho_baco1.dat
Ho_baco2.dat
Ho_baco3.dat
S_yag.dat
S_ygg.dat
S_yvo4.dat
W_luaso4.dat
W_lupo4.dat
W_luvo4.dat
W_scaso4.dat
W_scpo4.dat
W_scvo4.dat
W_yaso4.dat
W_ypo4.dat
W_yvo4.dat
Er_erp.wdt
Er_lup.wdt
Er_scv.wdt
Er_yp1.wdt
Er_yp2.wdt
Er_yv.wdt
Ho_hop.wdt
Ho_hov.wdt
Ho_yp.wdt
Nd_yv.wdt
Tm_lup.wdt
Tm_tmp.wdt