Commandline Usage
For xtb we usually enjoy to build our workflows via commandline,
so most tasks can be performed without ever writing any kind of input file
(except for the geometry input, of course).
The man page can be found here.
Note
If you need more control you should resort to the Detailed Input file.
Runtypes
The most basic flags used in xtb are the runtypes. We have a bunch of
them, but many of the elaborate composite runtypes are constructed from
four basic runtypes: singlepoint (SP), geometry optimization (ANCopt),
frequency calculation (Hessian) and molecular dynamics (MD).
Every calculation performs the basic setup and at some (resonable) point
a property calculation.
- Singlepoint
- flag:
--scc- description:
just self-consistent charge (SCC) calculation. See Singlepoint Calculations for details.
- queue:
setup, SP, properties
- Gradient
- flag:
--grad- description:
self-consistent charge (SCC) calculation, afterwards energy and gradient will be printed in a Turbomole readable format
- queue:
setup, SP, properties
- Vertical IP
- flag:
--vip- description:
vertical ionisation potential (IP), calculates SCC on input structure and than removes an electron to perform another SCC calculation.
- queue:
setup, SP, SP, properties
- Vertical EA
- flag:
--vea- description:
vertical electron affinity (EA), calculates SCC on input structure and than adds an electron to perform another SCC calculation.
- queue:
setup, SP, SP, properties
- Vertical IP and EA
- flag:
--vipea- description:
both IP and EA are calculate by removing and adding an electron, respectively.
- queue:
setup, SP, SP, SP, properties
- Global Electrophilicity Index
- flag:
--vomega- description:
global electrophilicity index from vertical IP and EA.
- queue:
setup, SP, SP, SP, properties
- Fukui Indices
- flag:
--vfukui- description:
calculates Mulliken partial charges from the neutral, positive and negatively charged structure and calculates Fukui indices.
- queue:
setup, SP, SP, SP, properties
- Dimer Projection Method DIPRO
- flag:
--dipro- description:
calculates the electronic coupling integrals J_ab and J_ab,eff between two fragments
- queue:
setup, SP, SP, SP, properties
- Electrostatic Potential
- flag:
--esp- description:
calculate electrostatic potential on VdW-grid
- queue:
setup, SP, properties (with ESP calculation)
- STM picture
- flag:
--stm- description:
simulate a STM measurement (molecule should be aligned to xy-plane)
- queue:
setup, SP, properties (with STM calculation)
- Geometry optimization
- flag:
--opt- description:
approximate normal coordinate optimization, performs an initial singlepoint calculation and a final singlepoint calculation on the optimized structure. See Geometry Optimization for details.
- queue:
setup, SP, ANCopt, SP, properties
- Minimum Hopping
- flag:
--metaopt- description:
try to find conformers by geometry optimization, for each minimum located a bias potential is generated to push the optimizer to another local minimum.
- queue:
setup, SP, ANCopt, SP, properties, ANCopt, …
- Guided Path Finder
- flag:
--path [file]- description:
apply a bias potential between the input and final geometry (from file) and force the geometry optimizer to generate a path between the two structures.
- queue:
setup, SP, properties, ANCopt, …
- Modefollowing
- flag:
--modef mode- description:
follow
modewhich specifies the nth eigenmode from a previously done frequency calculation.- queue:
setup, SP, properties, ANCopt, …
- Frequency calculation
- flag:
--[o]hess- description:
second derivative calculation, see Calculation of Vibrational Frequencies
- queue:
setup, SP, [ANCopt, SP,] SP, Hessian, properties
- Molecular dynamics
- flag:
--[o]md- description:
molecular dynamics simulation, see Molecular Dynamics Simulations for details
- queue:
setup, SP, [ANCopt, SP,] properties, MD
- Metadynamics
- flag:
--metadyn [snapshots]- description:
activates metadynamics simulation on start geometry, where
snapshotsis the number of structures from the trajectory should be used in the biasing potential. See Meta-Dynamics Simulations for details.- queue:
setup, SP, properties, MD
- Simulated annealing
- flag:
--siman- description:
performs a number of simulated annealing steps on the input coordinates and tries to find a conformer ensemble. We recommend the CREST workflow (see CREST documentation) instead of this runtyp since it is faster and more reliable in finding the lowest conformer. This runtyp has been deprecated and removed in version 6.2!
- queue:
setup, SP, properties, MD, ANCopt, …
Options
- -c, --chrg INT
specify molecular charge as INT, overrides
.CHRGfile andxcontroloption- -u, --uhf INT
specify Nalpha-Nbeta as INT, overrides
.UHFfile andxcontroloption- --gfn INT
specify parametrisation of GFN-xTB (default = 2)
- --etemp REAL
electronic temperature (default = 300K)
- -a, --acc REAL
accuracy for SCC calculation, lower is better (default = 1.0)
- --vparam FILE
Parameter file for vTB calculation
- –alpb SOLVENT [reference]
analytical linearized Poisson-Boltzmann (ALPB) model, available solvents are acetone, acetonitrile, aniline, benzaldehyde, benzene, ch2cl2, chcl3, cs2, dioxane, dmf, dmso, ether, ethylacetate, furane, hexadecane, hexane, methanol, nitromethane, octanol, woctanol, phenol, toluene, thf, water. The solvent input is not case-sensitive. The Gsolv reference state can be chosen as reference or bar1M (default).
- -g, –gbsa SOLVENT [reference]
generalized born (GB) model with solvent accessible surface (SASA) model, available solvents are acetone, acetonitrile, benzene (only GFN1-xTB), CH2Cl2, CHCl3, CS2, DMF (only GFN2-xTB), DMSO, ether, H2O, methanol, n-hexane (only GFN2-xTB), THF and toluene. The solvent input is not case-sensitive. The Gsolv reference state can be chosen as reference or bar1M (default).
- --cma
shifts molecule to center of mass and transforms cartesian coordinates into the coordinate system of the principle axis (not affected by
isotopes-file).- --pop
requests printout of Mulliken population analysis (done by default)
- --molden
requests printout of molden file
- --dipole
requests dipole printout (done by default)
- --wbo
requests Wiberg bond order printout (done by default)
- --lmo
requests localization of orbitals
- --fod
requests FOD calculation
- -I, --input FILE
use FILE as input source for
xcontrol(7)instructions- --namespace STRING
give this
xtb(1)run a namespace. All files, even temporary ones, will be named according to STRING.- --copy, --nocopy
copies the
xcontrolfile at startup (default = false)- --restart, --norestart
restarts calculation from
xtbrestart(default = true)- -P, --parallel INT
number of parallel processes
- --define
performs automatic check of input and terminate
- --citation
print citation and terminate
- --license
print license and terminate
- -v, --verbose
be more verbose (not supported in every unit)
- -s, --silent
clutter the screen less (not supported in every unit)
- --strict
turns all warnings into hard errors
- -h, --help
show help page