Dear all,
As is shown in the title, I tried to combine SF-TDDFT with FSSH to investigate S1->S0 process. For example, I tried this for ethylene.
Firstly, I performed a single point SF-TDDFT job to find singlet states. Below text is copied from output.
Excited state 1: excitation energy (eV) = -4.1688
Total energy for state 1: -78.52970653 au
<S**2> : 0.0130
S( 2) --> S( 1) amplitude = 0.9900 alpha
Excited state 2: excitation energy (eV) = 0.9231
Total energy for state 2: -78.34258383 au
<S**2> : 2.0177
S( 1) --> S( 1) amplitude = 0.7099 alpha
S( 2) --> S( 2) amplitude = -0.6948 alpha
Excited state 3: excitation energy (eV) = 3.9334
Total energy for state 3: -78.23195701 au
<S**2> : 1.0132
D( 7) --> S( 1) amplitude = 0.9888
Excited state 4: excitation energy (eV) = 4.2523
Total energy for state 4: -78.22023620 au
<S**2> : 0.0210
S( 1) --> S( 1) amplitude = 0.6990 alpha
S( 2) --> S( 2) amplitude = 0.7138 alpha
Excited state 5: excitation energy (eV) = 5.0981
Total energy for state 5: -78.18915523 au
<S**2> : 1.0067
S( 2) --> V( 1) amplitude = 0.9903 alpha
Hence, I hope to choose state 1 and 4 as states that to be considered in FSSH job. By applying “CIS_S2_Thresh 50”, it printed below error:
namdMethods: unable to find the active surface (2)
within the states used for this calculation
(below).
states = {1, 4}
It seemed that correct singlet states were selected, however, the keyword “FSSH_INITIALSURFACE 2” ordered the program to use state 2 as initial surface, not the second state used for this calculation.
I thought “FSSH_INITIALSURFACE 4” may solve this error, however, due to crossing points may (and surely) exist on the relaxation path, the state number may change.
I wonder if there is any method can order the program to use “second in selected states” instead of “second in all states”.
Below is my FSSH input:
$molecule
0 3
C 0.6690712511 -0.0268376644 0.0050315169
C -0.6396456893 -0.1886733266 -0.0420316825
H 1.1181981658 0.8267926667 0.4872420937
H 1.3455134717 -0.7411370258 -0.4366902395
H -1.0897934715 -1.0416754444 -0.5243097601
H -1.3163849942 0.5252327237 0.4000552941
$end
$rem
JOBTYPE aimd
METHOD BHHLYP
BASIS 6-31G(d,p)
SCF_MAX_CYCLES 128
CIS_N_ROOTS 5
CIS_MAX_CYCLES 128
SPIN_FLIP True
CIS_S2_Thresh 50
SYMMETRY off
SYM_IGNORE true
PROJ_TRANSROT true
FSSH_LOWESTSURFACE 1
FSSH_NSURFACES 2
FSSH_INITIALSURFACE 2
AFSSH 0
CALC_NAC true
AIMD_STEPS 1000
TIME_STEP 21
AIMD_SHORT_TIME_STEP 3
AIMD_TIME_STEP_CONVERSION 1
AIMD_PRINT 1
AIMD_INIT_VELOC thermal
AIMD_TEMP 300 # K
AIMD_INTEGRATION vverlet
FOCK_EXTRAP_ORDER 6
FOCK_EXTRAP_POINTS 12
$end