McPhase

USERS MANUAL

M. Rotter¹,

Duc Manh Le ²

Joachim Keller ³

Till Hoffmann ⁴,

P. Fabi né Hoffmann⁵,

S. Rotter ⁶

mcphas version 5.6 mcdisp version 5.6 mcdiff version 5.6

December 26, 2024

Acknowledgements
What is New ?
- ... in version 5.6 ...
- ...in version 5.5 ...
- ...in version 5.4 ...
- ...in version 5.3 ...
Contents
How To ... ?
Frequently asked Questions
Introduction
Getting Started ... List of Examples
The Hamiltonian
- Rare Earth Ions
- Intermediate Coupling
singleion - a Crystal Field Program for Calculating Energy Levels, Transition Matrix Elements etc.
- Doing Single Ion Calculations
- Example - how to evaluate the crystal field of NdCu using singleion
- Using the so1ion module in McPhase and McDisp
  - Module Tasks:
  - Module Usage:
mcphas - calculation of thermodynamic properties (Magnetisation, Susceptibility, Specific Heat, Neutron Diffraction, etc.)
- Input Files
- Starting a simulation
- Options for a running simulation
- Output Files - mcphas.qvc,phs,sps,mf,fum,j1...,xyt,hkl
mcdiff - calculate and fit magnetic Neutron or Resonant Xray Scattering
- How to generate and view a powder diffraction profile
- How to calculate only specific reflections, azimuth dependence and fitting of neutron intensities
- Formalism I - Resonant Magnetic Xray Scattering Intensity
- Formalism II - Neutron Cross section
- Going beyond the Dipole Approximation for the Neutron Form factor
mcdisp - the Calculation Program for Magnetic Excitations
- Viewing the results of McDisp
- Diffuse Scattering
- Powder Neutron Cross Section
- Resonant Inelastic X-ray Scattering(RIXS)
  - Scattering geometry
Including Quadrupolar and Higher Order Interactions
- Setting up mcphas.j and other input files
- Option indexexchange in order to shorten notation in mcphas.j
- Running McPhase and McDisp
Including Phonons and Crystal-Field Phonon interactions
- Using Single Ion Module phonon
Crystal Field Phonon Interaction
- Elastic Energy $E_{el}$
- Mixing term $H_{mix}$
- The lattice dynamic terms $H_{E}+H_{int}$
- The total Crystal field Phonon Interaction Hamiltonian
- Exchange Striction
- Progam Workflow for calculating Magnetoelastic Effects and the Static Jahn Teller Effect
- Calculation of the Elastic Constants using makenn
- Calculation of the Crystal Field Phonon Interaction using a Point Charge Model
- Setting up a Point Charge Model which yields given Crystal Field Parameters
- Calculation of the Exchange Striction Parameters using makenn
- Magnetoelastic Options to mcphas
- TmCu - magnetoelastic effects and Neutron Spectra calculated with CF-phonon interaction
- Project - Extending McPhase to include Stress tensor
Single Ion Modules
- Landé Factor
- Magnetic Formfactor Coefficients
- Debye Waller Factor
- Nuclear Neutron Scattering Length
- Radial Wavefunction
- Radial Matrix Elements
All about Programming External Single Ion Modules
- Basic Module Functions
- Module Functions for Observables
ic1ion - a module for intermediate coupling
- using ic1ion as a stand-alone program to do crystal field calculations
- cpic1ion - calculation of the specific heat from ic1ion.out
- using ic1ion as a module in mcphas,mcdiff,mcdisp,...
- icf1ion - Intermediate Crystal Field module
- Formalism
- Formalism for going beyond the dipolar approximation
bfk - Inelastic neutron-scattering from RE ions in a crystal field including damping effects due to the exchange interaction with conduction electrons
Programs for Graphical display of calculated data
- Programs display, displaybubbles, displaycontour, displaytext and show - graphical display of any xy data such as magnetisation etc.
- Programs display_density - display of the charge- spin- moment- current- density of a single ion
- Programs display_densities - display of the superstructure and excitations
- Program hkl, hkl2d and mcdiff - graphical display of magnetic diffraction intensity
- Program phased - graphical display of magnetic phase diagrams
- Program felog - display logged free energy for different moment configurations at a temperature/field (linux with pgplot grphic library only)
Searchspace and Simannfit - Fitting Experimental Data
- Setting up parameter files for fitting
- Telling the fitting program, how to calculate the standard deviation sta which should be minimised
- Starting a parameter space search
- analysing the results of searchspace
- Starting a fit
- Stopping a fit/parameter space search
- Fitting is an art: some general remarks
- Crystal Field Example: Fitting Point Charges to Inverse Susceptibility Data
Programs for Specific Tasks in the World of McPhase
Programs for Manipulation of Columns and Lines in Data Files
Programs of General Interest
Module kramer - a Kramers Ground State Doublet Single Ion Module
Module brillouin - an Isotropic Spin Single Ion Module
DyNiBC - single ion module
ErNiBC - single ion module
Crystal Field and Parameter Conventions
Tesseral Harmonics
Stevens Operators
Symmetry considerations for Crystal Field Parameters
Transforming Crystal Field Parameters by Rotation of the Coordinate System
- Forward Rotation Matrices
- Reverse Rotation Matrices
Magnetic Form factors for Neutrons
Magnetic Form factors for Neutrons- ZK coefficients for Rare Earth Ions
Derivation of the Chargedensity Formula
Dynamical Susceptibility and Excitations - Formalism for mcdisp
- DMD - formalism
- Calculation of the Correlation Function of Physical Observables
- Evaluating results - Graphical Visualisation of Spin and Charge Oscillations of Excitations
- Application to Neutron scattering
  - Coherent Nuclear Inelastic Scattering - 1 Phonon processes
  - Magnetic inelastic Scattering
- Dipole Approximation
Theory for program bfk - Inelastic neutron-scattering from RE ions in a crystal field including damping effects due to the exchange interaction with conduction electrons
Solution of the exercises
Unit Conventions in McPhase
Installation of the program package
References
Index
Shortlist of important Commands and Input Files
About this document ...

McPhase USERS MANUAL

McPhase

USERS MANUAL