McXtrace logo

McXtrace - An X-ray ray-trace simulation package

Synchrotron SOLEIL DTU Physics

McXtrace

About McXtrace
 Publications
 Project Partners
 Project People
 Goal

Download
 Components

Documentation
 Manual
 Commands
 Wiki (GitHub)
 Tutorial

Mailing list

Links

Search

Code-repository (GitHub)

Report bugs (GitHub)


McStas: Molecule_2state

[ Identification | Description | Input parameters | Output parameters | Links ]

The Molecule_2state Component

Disordered optical-excitable molecule sample.

Identification

  • Site:
  • Author: Erik B Knudsen
  • Origin: DTU Physics
  • Date: October 2012

Description

A sample model for pump probe experiments which models disordered molecules in a volume (rectangular,
cylindrical, or spherical). Molecules can be in one of two states (0 and 1).
Scattering is either specified through F vs. q scattering curves or as a set of atom positions from which
F vs. q is computed.
At t=-delta_t, a fraction of the molecules are put in state 1, from which they decay exponentially,
with time constant t_relax, into state 0. For t<-delta_t
all of the molecules are in the state specified by initial_state.
To improve statistics, scattering may be limited to a "forward" cone with opening angle in [psimin, psimax].
Furthermore, scattering may be restricted to the azimuthal segment between [etamin,etamax].

Input parameters

Parameters in boldface are required; the others are optional.
NameUnitDescriptionDefault
delta_t(s) Delay between the exciting event t=0. delay is negative, i.e. delta_t>0 means the exciting event happens before t=0.100e-9
excitation_yield( ) Mean fraction of molecules that get excited.0.2
t_relax(s) Mean relaxation time (into state 0) of excited molecules.100e-9
initial_state( ) Which state is Molecule_2state in for t0
psimin(rad) Minimum scattering angle off the optical axis.0
psimax(rad) Maximum scattering angle off the optical axis.M_PI_2
etamin(rad) Minimum scattering angle around the optical axis.-M_PI
etamax(rad) Maximum scattering angle around the optical axis.M_PI
radius(m) Radius of cylindrical of spherical sample.0
yheight(m) Height of rectangular or cylindrical sample.0
xwidth(m) Width of rectangular sample.0
zdepth(m) Depth (thickness) of rectangular sample.0
concentration(m) Concentration or packing factor of sample.1
p_transmit(m) Fraction of statistics devoted to sample direct (unscattered) beam.0.1
form_factors( ) File from which to read atomic form factors. Defualt amounts to use the one shipped with McXtrace."FormFactors.txt"
state_0_file( ) Isotropic scattering factors (parameterized by q), or atom positions are specified for state 0.NULL
state_1_file( ) Isotropic scattering factors (parameterized by q), or atom positions are specified for state 1.NULL
nq( ) Number of q-bins if F is to be computed from atom positions (Debye formalism).512
material_datafile( ) Where to read f1 and f2 factors from in order to handle absorption."Be.txt"
q_parametric( ) 0: Assume that datafiles contains atom positions. 1: datafiles contains F vs. q data.0
Emax( ) Maximal energy for which scattering factors are computed. Must be larger than the maximal impinging energy.80

Output parameters

Parameters in boldface are required; the others are optional.
NameUnitDescriptionDefault

Links


[ Identification | Description | Input parameters | Output parameters | Links ]

Generated on 2022-02-07 20:46:44


Last Modified: Wednesday, 11-May-2022 22:46:12 CEST
Search website mailinglist archive GitHub repos