#! Benzene Dimer CCSD(T)/heavy-aug-cc-pVDZ
#
#  This test case comes from studies of the benzene dimer published in
#  C. D. Sherrill, T. Takatani, and E. G. Hohenstein,
#  J. Phys. Chem. A 113, 10146 (2009) [doi: 10.1021/jp9034375]
#
#  The original study used conventional CCSD(T).  Here we test our
#  density-fitted, frozen natural orbital code.  In this particular case,
#  the DF and FNO approximations do not change the counterpoise-corrected
#  interaction energy, which is reported in the paper as -1.33 kcal/mol,
#  and computed here as
#  (-463.221986685419 - 2*(-231.609931343188))*627.509 = -1.33 kcal/mol

refnuc    =  614.0996704247507978 #TEST
refscf    = -461.4496976036579099 #TEST
refccsd_t = -463.221986685419     #TEST

molecule bz2 {
    X
    X   1  RXX
    X   2  RXX  1  90.0
    C   3  RCC  2  90.0  1   0.0
    C   3  RCC  2  90.0  1  60.0
    C   3  RCC  2  90.0  1 120.0
    C   3  RCC  2  90.0  1 180.0
    C   3  RCC  2  90.0  1 240.0
    C   3  RCC  2  90.0  1 300.0
    H   3  RCH  2  90.0  1   0.0
    H   3  RCH  2  90.0  1  60.0
    H   3  RCH  2  90.0  1 120.0
    H   3  RCH  2  90.0  1 180.0
    H   3  RCH  2  90.0  1 240.0
    H   3  RCH  2  90.0  1 300.0
    X   3  RXX  2  90.0  1   0.0
    X   3  D   16  90.0  2 180.0
    X   3  DRXX 16 90.0  2 180.0
    X  18  RXX 17  90.0 16   0.0
    C  17  RCC 18  90.0 19   0.0
    C  17  RCC 18  90.0 19  60.0
    C  17  RCC 18  90.0 19 120.0
    C  17  RCC 18  90.0 19 180.0
    C  17  RCC 18  90.0 19 240.0
    C  17  RCC 18  90.0 19 300.0
    H  17  RCH 18  90.0 19   0.0
    H  17  RCH 18  90.0 19  60.0
    H  17  RCH 18  90.0 19 120.0
    H  17  RCH 18  90.0 19 180.0
    H  17  RCH 18  90.0 19 240.0
    H  17  RCH 18  90.0 19 300.0

    RCC  = 1.3915
    RCH  = 2.4715
    RXX  = 1.00
    D    = 4.0
    DRXX = 4.90

}

memory 4000 mb

set globals {
  basis heavy-aug-cc-pVDZ
  guess sad
  freeze_core true
  scf_type df
  cc_type df
}


thisenergy = energy('fno-ccsd(t)')

compare_values(refnuc, bz2.nuclear_repulsion_energy(), 8, "Nuclear repulsion energy")       #TEST
compare_values(refscf, get_variable("SCF TOTAL ENERGY"),     8, "SCF energy") #TEST
compare_values(refccsd_t, thisenergy,     6, "CCSD(T) energy") #TEST