DOKK / manpages / debian 12 / gromacs-data / gmx-sans.1.en
GMX-SANS(1) GROMACS GMX-SANS(1)

gmx-sans - Compute small angle neutron scattering spectra

gmx sans [-s [<.tpr>]] [-f [<.xtc/.trr/...>]] [-n [<.ndx>]]


         [-d [<.dat>]] [-pr [<.xvg>]] [-sq [<.xvg>]]


         [-prframe [<.xvg>]] [-sqframe [<.xvg>]] [-b <time>]


         [-e <time>] [-dt <time>] [-tu <enum>] [-xvg <enum>]


         [-bin <real>] [-mode <enum>] [-mcover <real>]


         [-method <enum>] [-[no]pbc] [-grid <real>] [-startq <real>]


         [-endq <real>] [-qstep <real>] [-seed <int>]


gmx sans computes SANS spectra using Debye formula. It currently uses topology file (since it need to assigne element for each atom).

Parameters:

-pr Computes normalized g(r) function averaged over trajectory

-prframe Computes normalized g(r) function for each frame

-sq Computes SANS intensity curve averaged over trajectory

-sqframe Computes SANS intensity curve for each frame

-startq Starting q value in nm

-endq Ending q value in nm

-qstep Stepping in q space

Note: When using Debye direct method computational cost increases as 1/2 * N * (N - 1) where N is atom number in group of interest.

WARNING: If sq or pr specified this tool can produce large number of files! Up to two times larger than number of frames!

Options to specify input files:

Portable xdr run input file
Trajectory: xtc trr cpt gro g96 pdb tng
Index file
Generic data file

Options to specify output files:

xvgr/xmgr file
xvgr/xmgr file
xvgr/xmgr file
xvgr/xmgr file

Other options:

Time of first frame to read from trajectory (default unit ps)
Time of last frame to read from trajectory (default unit ps)
Only use frame when t MOD dt = first time (default unit ps)
Unit for time values: fs, ps, ns, us, ms, s
xvg plot formatting: xmgrace, xmgr, none
[HIDDEN]Binwidth (nm)
Mode for sans spectra calculation: direct, mc
Monte-Carlo coverage should be -1(default) or (0,1]
[HIDDEN]Method for sans spectra calculation: debye, fft
-[no]pbc (yes)
Use periodic boundary conditions for computing distances
[HIDDEN]Grid spacing (in nm) for FFTs
Starting q (1/nm)
Ending q (1/nm)
Stepping in q (1/nm)
Random seed for Monte-Carlo

gmx(1)

More information about GROMACS is available at <http://www.gromacs.org/>.

2023, GROMACS development team

February 3, 2023 2022.5