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
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 mode which 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 Dyamics Simulations for details
queue:setup, SP, [ANCopt, SP,] properties, MD
Metadynamics
flag:--metadyn [snapshots]
description:activates metadynamics simulation on start geometry, where snapshots is 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 Introduction to CREST) 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 .CHRG file and xcontrol option
-u, --uhf INT specify Nalpha-Nbeta as INT, overrides .UHF file and xcontrol option
--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
-g, –gbsa SOLVENT [reference] [grid]
generalized born (GB) model with solvent accessable 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). The SASA grid can be specified with normal (default), tight, verytight and extreme.
--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 xcontrol file 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