Link Search Menu Expand Document

MECP Screening

(Semi-automated) Screening of benzene MECPs with GFN2-xTB


(Semi-automated) Screening of benzene MECPs with GFN2-xTB

An extension of the minimum energy crossing point optimization, is the metadynamics-based screening (analogously to conformational sampling). It can be called via the new input file reader . Again, for the GFN2-xTB S0/T1 MECPs of benzene:

crest --input input.toml
 C          1.3830400000       -0.2213700000        0.0054100000
 C          0.8812100000        1.0799600000        0.0137400000
 C         -0.4965300000        1.2961400000        0.0106300000
 C         -1.3728900000        0.2109800000       -0.0044700000
 C         -0.8710300000       -1.0904600000       -0.0146100000
 C          0.5067700000       -1.3067000000       -0.0079300000
 H          2.4566500000       -0.3899700000        0.0090900000
 H          1.5639800000        1.9254500000        0.0228700000
 H         -0.8876100000        2.3099700000        0.0197800000
 H         -2.4463500000        0.3796100000       -0.0082500000
 H         -1.5536800000       -1.9359000000       -0.0272900000
 H          0.8977800000       -2.3206600000       -0.0132700000
#This is a CREST input file
input = ''
runtype='mecp_search'   # MECP sampling runtype

threads = 10

#calculation data
eprint = true

[[calculation.mecp]]  # This block automatically sets up a uhf=0 and uhf=2 calculation with xtb
method = "xtb"
binary = "xtb"
flags = "--gfn 2 --grad"

gapdiff2 = [7.5, 0.005, 0.25]

#molecular dynamics data, required for MECP sampling runtype
length = 10.0
tstep = 2.5 
dump = 100.0
hmass = 4

The sampling algorithm will run in parallel several (i.e., ten) metadynamics simulations on the mixed PES including the gap potential and MECP-optimize the output trajectories. While the metadynamics bias potentials are set up automatically, the user is responsible for setting the MD parameters, such as the simulation lengths in ps. Some benzene MECPs that can be found with this method are shown below (in comparison with FOMO-CASCI(6,5) structures in transparent blue).

Benzene MECPs
Some GFN2-xTB S0/T1 MECPs for benzene, found with semi-automated metadynamics sampling. Transparent blue are FOMO-CASCI(6,5) reference structures.

Back to top

Copyright © 2022-2024 Philipp Pracht.

CREST is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.