Example 7.111 Input for a RAS-2SF-CI calculation of three states of the DDMX tetraradical using RASCI1. The active space (RAS2) contains electrons in the singly occupied orbitals in the ROHF quintet reference. Natural orbital occupancies are requested.
$molecule 0 5 C 0.000000 0.000000 1.092150 C -1.222482 0.000000 0.303960 C -2.390248 0.000000 1.015958 H -2.344570 0.000000 2.095067 H -3.363161 0.000000 0.537932 C -1.215393 0.000000 -1.155471 H -2.150471 0.000000 -1.702536 C 0.000000 0.000000 -1.769131 C 1.215393 0.000000 -1.155471 H 2.150471 0.000000 -1.702536 C 1.222482 0.000000 0.303960 C 2.390248 0.000000 1.015958 H 2.344570 0.000000 2.095067 H 3.363161 0.000000 0.537932 $end $rem EXCHANGE hf CORRELATION rasci BASIS 6-31g UNRESTRICTED false MEM_TOTAL 4000 MEM_STATIC 100 RAS_ROOTS 3 RAS_ACT 4 RAS_ELEC 4 RAS_OCC 25 RAS_SPIN_MULT 0 RAS_NATORB true $end
Example 7.112 Input for a RAS-2IP-CI calculation of triplet states of F molecule using the dianion closed shell F as the reference determinant. RASCI1 code is used
$molecule -2 1 F F 1 1.4136 $end $rem EXCHANGE hf CORRELATION rasci BASIS cc-pVTZ MEM_TOTAL 4000 MEM_STATIC 100 RAS_ROOTS 2 RAS_ACT 6 RAS_ELEC 10 RAS_OCC 4 RAS_SPIN_MULT 3 $end
Example 7.113 Input for a FCI/STO-3G calculation of water molecule expanding the RAS2 space to the entire molecular orbital set. RASCI code is used.
$molecule 0 1 O 0.000 0.000 0.120 H -0.762 0.000 -0.479 H 0.762 0.000 -0.479 $end $rem EXCHANGE hf CORRELATION rasci BASIS sto-3g MEM_TOTAL 4000 MEM_STATIC 100 RAS_ROOTS 1 RAS_ACT 7 RAS_ELEC 10 RAS_OCC 0 RAS_SPIN_MULT 1 RAS_DO_HOLE false RAS_DO_PART false $end
Example 7.114 Methylene single spin-flip calculation using RASCI2
$molecule 0 3 C 0.0000000 0.0000000 0.0000000 H -0.8611113 0.0000000 0.6986839 H 0.8611113 0.0000000 0.6986839 $end $rem EXCHANGE HF CORRELATION RASCI2 BASIS cc-pVDZ AUX_BASIS rimp2-cc-pVDZ UNRESTRICTED false RAS_ACT_OCC 1 ! # alpha electrons RAS_ACT_VIR 1 ! # virtuals in active space RAS_ACT_DIFF 0 ! # set to 1 for odd # of e-s RAS_N_ROOTS 4 SET_ITER 25 ! number of iterations in RASCI $end
Example 7.115 Two methylene separated by 10 Å; double spin-flip calculation using RASCI2. Note that the values for this case will not be uniquely defined at the triply-degenerate ground state.
$molecule 0 5 C 0.0000000 0.0000000 0.0000000 H -0.8611113 0.0000000 0.6986839 H 0.8611113 0.0000000 0.6986839 C 0.0000000 10.0000000 0.0000000 H -0.8611113 10.0000000 0.6986839 H 0.8611113 10.0000000 0.6986839 $end $rem EXCHANGE HF CORRELATION RASCI2 BASIS cc-pVDZ AUX_BASIS rimp2-cc-pVDZ RAS_ACT_OCC 2 ! # alpha electrons RAS_ACT_VIR 2 ! # virtuals in active space RAS_ACT_DIFF 0 ! # set to 1 for odd # of e-s UNRESTRICTED false RAS_N_ROOTS 8 SET_ITER 25 $end
Example 7.116 RASCI2 calculation of the nitrogen cation using double spin-flip.
$molecule 1 6 N N 1 4.5 $end $rem EXCHANGE HF CORRELATION RASCI2 BASIS 6-31G* AUX_BASIS rimp2-VDZ RAS_ACT_OCC 3 ! # alpha electrons RAS_ACT_VIR 3 ! # virtuals in active space RAS_ACT_DIFF 1 ! # for odd # e-s, cation UNRESTRICTED false N_FROZEN_CORE 2 N_FROZEN_VIRTUAL 2 RAS_N_ROOTS 8 SET_ITER 25 $end
Example 7.117 RAS(h,p)-1SF calculation of the nitrogen cation using LibRASSF.
$molecule 0 7 N N 1 1.75 $end $rem EXCHANGE HF CORRELATION RASCI2 BASIS cc-pvdz LIBRASSF 1 RASSF_DELTA_ALPHA 1 RASSF_DELTA_BETA 1 RAS_N_ROOTS 4 RAS_DO_HOLE 1 RAS_DO_PART 1 RAS_NATORB 0 $end