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[ Identification | Description | Input 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]. Example: Molecule_2state( nq=512,state_0_file="Fe_bpy_GS_DFT.txt",state_1_file="Fe_bpy_ES_DFT.txt",radius=0.01, psimin=0, psimax=15*DEG2RAD, etamin=-1*DEG2RAD,etamax=1*DEG2RAD, t_relax=600e-12, delta_t=100e-9, excitation_yield=0.2)
Input parameters
Parameters in boldface are required; the others are optional.| Name | Unit | Description | Default | |
| 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 | 1 | 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 | 0/1 | Which state is Molecule_2state in for t| 0 | | |
| 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 | str | File from which to read atomic form factors. Defualt amounts to use the one shipped with McXtrace. | "FormFactors.txt" | |
| state_0_file | str | Isotropic scattering factors (parameterized by q), or atom positions are specified for state 0. | NULL | |
| state_1_file | str | Isotropic scattering factors (parameterized by q), or atom positions are specified for state 1. | NULL | |
| nq | 1 | Number of q-bins if F is to be computed from atom positions (Debye formalism). | 512 | |
| material_datafile | str | Where to read f1 and f2 factors from in order to handle absorption. | "Be.txt" | |
| q_parametric | 0/1 | When 0: Assume that datafiles contains atom positions. 1: datafiles contains F vs. q data. | 0 | |
| Emax | keV | Maximal energy for which scattering factors are computed. Must be larger than the maximal impinging energy. | 80 |
| AT ( | , | , | ) RELATIVE | |||
|---|---|---|---|---|---|---|
| ROTATED ( | , | , | ) RELATIVE |
Links
- Source code for
Molecule_2state.comp.
[ Identification | Description | Input parameters | Links ]
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