Modules and Operators

Descpription of modules system: available modules, operators, and ascociated options.

The modules system is how you interact with ampsci after the wavefunction has been calculated. Any number of modules can be run in the same job to compute matrix elements, polarisabilities, QED corrections, structure radiation, and more.

• See Matrix Elements for a hands-on introduction to using modules.
• The modules system allows the easy calculation of any atomic properties after the wavefunction has been calculated.
• Any number of modules can be run by adding Module::moduleName{} blocks.
• The code is designed so that you can easily create your own modules – see Writing custom modules.
• You can also write your own operators – see Writing a custom operator.

Getting started with modules

Get a list of available modules: ./ampsci -m

Output will look something like this (example):

Available modules: 
 * WriteOrbitals
     Write orbitals to disk for plotting
 * matrixElements
     Calculates matrix elements of any operator
 * CI_matrixElements
     Calculates matrix elements of any operator for CI wavefunctions
 * polarisability
     Calculates static polarisabilities
 * dynamicPolarisability
     Calculates dynamic polarisabilities
 * transitionPolarisability
     Calculates transition polarisabilities
 * structureRad
     Calculates Struct. Rad + Normalisation corrections to MEs
 * fieldShift
     Calculates field-shift constants (isotope shift)
 * QED
     QED corrections to energies/matrix elements
 * Breit
     Breit corrections to energies
 * Kionisation
     Calculate atomic ionisation form-factors
 * exampleModule
     A short description of the module

You can also get most of this information directly from the command-line:

• ./ampsci -m <ModuleName>
  • Prints list of available Modules (same as –modules)
  • ModuleName is optional. If given, will list available options for that Module
  • Note the output is in the same format as required by the input file - you can copy+paste this into your input file.

./ampsci -m MatrixElements

// Available Module::MatrixElements options/blocks
Module::MatrixElements{
  // e.g., E1, hfs (see ampsci -o for available operators)
  operator;
  // options specific to operator (see ampsci -o 'operator')
  options{}
  // Method used for RPA: true(=TDHF), false, TDHF, basis, diagram [true]
  rpa;
  // Text or number. Freq. for RPA (and freq. dependent operators). Put 'each'
  // to solve at correct frequency for each transition. [0.0]
  omega;
  // print <a|h|b> and <b|h|a> [false]
  printBoth;
  // If true (and spectrum available), will use spectrum for valence states
  // [false]
  use_spectrum;
  // Calculate diagonal matrix elements (if non-zero) [true]
  diagonal;
  // Calculate off-diagonal matrix elements (if non-zero) [true]
  off-diagonal;
  // Options for Structure Radiation and normalisation (details below)
  StructureRadiation{}
}
 
 
// Available StructureRadiation options/blocks
StructureRadiation{
  // If this block is included, SR + Normalisation corrections will be included
 
  // true/false/filename - SR: filename for QkTable file. If blank will not use
  // QkTable; if exists, will read it in; if doesn't exist, will create it and
  // write to disk. If 'true' will use default filename. Save time (10x) at cost
  // of memory. Note: Using QkTable implies splines used for diagram legs
  Qk_file;
  // list; min,max n for core/excited: [1,inf]
  n_minmax;
}