TDDFT S0/T MECP optimization

I am attempting an optimization between the closed-shell singlet surface and the lowest TDDFT triplet with wB97M-V/pcseg-1.

  1. Calculation hangs when attempting to carry out finite difference gradient evaluation for state 0 (closed-shell singlet). (No, not using solvent).
  2. While I dont know what the situations is for gradients for wB97M-V TDDFT, there are analytic gradients for DFT. Why is it attempting a finite difference gradient evaluation for this?

I can do this same computation with CCSD / EOM-CCSD no problem with the X_OPT rems.

I’ll post the input / point of failure briefly.

$comment
  Plain old SCF on the ground state.
$end

$molecule
  0   1
  Fe
  C   1 rFeC_Head
  C   1 rFeC_Tail 2 a_CH_CT
  C   1 rFeC_Legs 2 a_CH_CL 3 d_CL_Fe_CH_CT
  C   1 rFeC_Legs 2 a_CH_CL 3 d_nCL_Fe_CH_CT
  O   1 rFeO_Head 3 a_OH_CT 4 d_OH_Fe_CT_CL
  O   1 rFeO_Tail 2 a_CH_OT 4 d_OT_Fe_CH_CL
  O   1 rFeO_Legs 2 a_CH_OL 3 d_OL_Fe_CH_CT
  O   1 rFeO_Legs 2 a_CH_OL 3 d_nOL_Fe_CH_CT

  rFeC_Head      =    1.79725
  rFeC_Tail      =    1.86590
  rFeC_Legs      =    1.85594
  rFeO_Head      =    2.95282
  rFeO_Tail      =    3.00647
  rFeO_Legs      =    3.00400
  a_CH_CT        =  112.34031
  a_OH_CT        =  111.71415
  a_CH_OT        =  109.99256
  a_CH_CL        =   88.57562
  a_CH_OL        =   88.46352
  d_nCL_Fe_CH_CT = -105.30500
  d_nOL_Fe_CH_CT = -106.09600
  d_CL_Fe_CH_CT  =  105.30500
  d_OL_Fe_CH_CT  =  106.09600
  d_OH_Fe_CT_CL  =   94.57550
  d_OT_Fe_CH_CL  = -105.28450
$end

$rem
  METHOD               wB97M-V
  UNRESTRICTED         FALSE
  BASIS                PCSEG-1
  SYMMETRY             FALSE
  SYM_IGNORE           TRUE
  GEN_SCFMAN           TRUE
  SCF_ALGORITHM        DIIS_GDM
  SCF_CONVERGENCE      8
  MAX_SCF_CYCLES       200
  MEM_TOTAL            16000
  MEM_STATIC           1000
  THRESH               14
$end

@@@

$comment
  Optimization of the S0/T MECP structure at wB97M-V.
$end

$molecule
  0   1
  Fe
  C   1 rFeC_Head
  C   1 rFeC_Tail 2 a_CH_CT
  C   1 rFeC_Legs 2 a_CH_CL 3 d_CL_Fe_CH_CT
  C   1 rFeC_Legs 2 a_CH_CL 3 d_nCL_Fe_CH_CT
  O   1 rFeO_Head 3 a_OH_CT 4 d_OH_Fe_CT_CL
  O   1 rFeO_Tail 2 a_CH_OT 4 d_OT_Fe_CH_CL
  O   1 rFeO_Legs 2 a_CH_OL 3 d_OL_Fe_CH_CT
  O   1 rFeO_Legs 2 a_CH_OL 3 d_nOL_Fe_CH_CT

  rFeC_Head      =    1.79725
  rFeC_Tail      =    1.86590
  rFeC_Legs      =    1.85594
  rFeO_Head      =    2.95282
  rFeO_Tail      =    3.00647
  rFeO_Legs      =    3.00400
  a_CH_CT        =  112.34031
  a_OH_CT        =  111.71415
  a_CH_OT        =  109.99256
  a_CH_CL        =   88.57562
  a_CH_OL        =   88.46352
  d_nCL_Fe_CH_CT = -105.30500
  d_nOL_Fe_CH_CT = -106.09600
  d_CL_Fe_CH_CT  =  105.30500
  d_OL_Fe_CH_CT  =  106.09600
  d_OH_Fe_CT_CL  =   94.57550
  d_OT_Fe_CH_CL  = -105.28450
$end

$rem
  JOBTYPE              OPT
  METHOD               wB97M-V
  UNRESTRICTED         FALSE
  BASIS                PCSEG-1
  SYMMETRY             FALSE
  SYM_IGNORE           TRUE
  GEN_SCFMAN           TRUE
  SCF_GUESS            READ
  SCF_ALGORITHM        GDM
  SCF_CONVERGENCE      8
  MAX_SCF_CYCLES       200
  CIS_N_ROOTS          2
  CIS_TRIPLETS         TRUE 
  CIS_SINGLETS         FALSE
  MECP_OPT             TRUE
  MECP_METHODS         BRANCHING_PLANE
  MECP_PROJ_HESS       TRUE
  GEOM_OPT_COORDS      0
  MECP_STATE1          [0,0]
  MECP_STATE2          [1,1]
  MEM_TOTAL            16000
  MEM_STATIC           1000
  THRESH               14
$end

Hangs here:

 ---------------------------------------------------
         TDDFT/TDA Excitation Energies
 ---------------------------------------------------

 Excited state   1: excitation energy (eV) =      -0.0580
 Total energy for state   1:                 -1716.63005405 au
    Multiplicity: Triplet
    Trans. Mom.:  0.0000 X   0.0000 Y   0.0000 Z
    Strength   :     0.0000000000
    D(   40) --> V(    1) amplitude =  0.2424
    D(   41) --> V(    1) amplitude =  0.8861
    D(   41) --> V(    9) amplitude = -0.2603

 Excited state   2: excitation energy (eV) =       0.7314
 Total energy for state   2:                 -1716.60104318 au
    Multiplicity: Triplet
    Trans. Mom.:  0.0000 X   0.0000 Y   0.0000 Z
    Strength   :     0.0000000000
    D(   40) --> V(    1) amplitude =  0.8611
    D(   40) --> V(    9) amplitude = -0.3190
    D(   41) --> V(    1) amplitude = -0.2543

 Finite difference gradient evaluation for state   0
 Ground state energy  =   -1716.6279215899

I don’t think the TDDFT analytic gradient is implemented for VV10-containing functionals. For other meta-GGAs the gradient was added in Q-Chem v.5.3

The finite difference error may originate in a recently introduced bug, please contact Q-Chem support to see if there is a workaround.