Files:  inv-pes-xyz-090129.pax  pes-gr-090210.pax  README  t0s.xyz  t0t.xyz  test_h2c2o1_st.f90 pes_h2c2o1s.f90  pes_h2c2o1t.f90

1. Untar both .pax files:
  tar xf inv-pes-xyz-090129.pax
  tar xf pes-gr-090210.pax

2. Create "mod" directory in home:
  mkdir $HOME/mod

3.  Assuming your system knows how to compile with lapack (otherwise modify Makefile):
  cd inv
  make realclean
  make libinv.a

4. cd ../pes-xyz
   make realclean
   make lib

5. The steps 3-4 produced three libraries: inv/libinv.a,  pes-xyz/libpes.a, pes-xyz/libpx.a  Only 
   libpes.a needs to be linked

6. The libraries can now be used, as shown in the example file.  The following steps describe its compilation and use

   Compile the file (it takes long time 10 min to hours), with command similar to: 
   ifort test_h2c2o1_st.f90 -L pes-xyz -I $HOME/mod -lpes -o test.x

7.  Run energies of points in t0s.xyz or t0t.xyz, doing (using t0s.xyz as example)
    ./test.x pes-gr-090210/h2c2o1s-avtz-rccpt-fit pes-gr-090210/h2c2o1t-avtz-rccpt-fit t0s.xyz
