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

–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 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