QENS Data Analysis in Mantid Sanghamitra Mukhopadhyay ISIS

QENS Data Analysis in Mantid Sanghamitra Mukhopadhyay ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX 11 0 QX

Motivation • Development of tools for the purpose of fitting of QENS data • Development of tools for the purpose of analysis of QENS data using model fitting – – Convolution with instrument resolutions Quantitative understanding of the quality of peak fitting Sequential fitting and multidimensional data fitting Fitting using Bayesian methodology – – Jump diffusion model Rotational diffusion model Diffusion in a cage … When no model exist ! • Absorption corrections and multiple scattering • High throughput QENS data analysis – Dealing scattering from containers at high temperatures and pressures – Dealing multiple scattering where it is applicable – Doing all above quickly and correctly

QENS at ISIS IRIS Indirect geometry instrument

QENS at ISIS OSIRIS Indirect geometry instrument 25. 4 0. 18 99. 0 0. 36

QENS Data Analysis at ISIS Software • MODES (1987) – Open. Genie based with users interface, Developed at ISIS by Spencer Howell and others • Mantid (2012) – Python and C++ based. Active Developments are continuing at ISIS. Documentations Nine RAL Technical reports in addition with on-line Mantid documentation pages

QENS Data Analysis Workflow Experiment Data Reduction Mean Square Displacements Integration of elastic window Elastic intensity with temperature Is there QENS signal ? Yes Discard results Fourier Transform Very weak signal Calculate moments No Fit with Lorentzians Fit with exponentials Calculate EISF Model fitting for dynamics No model exists ! MD simulations

QENS Data Analysis in Mantid https: //www. mantidproject. org/Indirect: Indirect_Data_Analysis

QENS Data Analysis in Mantid Elastic window scan

QENS Data Analysis in Mantid Elastic window scan

QENS Data Analysis in Mantid Elastic window scan MSD can be calculated by fitting a straight line in the plot of elastic window scan.

QENS Data Analysis in Mantid I(q, t) = FT[S’(Q, E)]

QENS Data Analysis in Mantid I(q, t) Fit Available functions • • Exponential Two exponentials Stretched exponential One stretched + exponential 75 functions are available for fitting in Mantid!

QENS Data Analysis in Mantid I(q, t) Fit Available functions • • Exponential Two exponentials Stretched exponential One stretched + exponential FABADA minimiser 75 functions are available for fitting in Mantid!

QENS Data Analysis in Mantid I(q, t) Fit Available functions • • Exponential Two exponentials Stretched exponential One stretched + exponential FABADA minimiser 75 functions are available for fitting in Mantid! Sequential fitting

QENS Data Analysis in Mantid I(q, t) Fit Available functions • • Exponential Two exponentials Stretched exponential One stretched + exponential 75 functions are available for fitting in Mantid! http: //docs. mantidproject. org/nightly/fitfunctions/categories/Fit. Functions. html

I(q, t) Fit

QENS Data Analysis in Mantid Convolution Fit Available functions • • Lorentzian Two Lorentzians Inelastic diff sphere Inelastic diff rotation circle Elastic diff sphere Elastic diff rotation circle Stretched exponential FT

QENS Data Analysis in Mantid Convolution Fit Available functions • • Lorentzian Two Lorentzians Inelastic diff sphere Inelastic diff rotation circle Elastic diff sphere Elastic diff rotation circle Stretched exponential FT FABADA minimiser

QENS Data Analysis in Mantid Convolution Fit Available functions • • Lorentzian Two Lorentzians Inelastic diff sphere Inelastic diff rotation circle Elastic diff sphere Elastic diff rotation circle Stretched exponential FT FABADA minimiser Sequential fitting

QENS Data Analysis in Mantid Convolution Fit Results

QENS Data Analysis in Mantid Jump Fit Available functions • • Chudley-Elliot Hall Ross Fickian diffusion Teixeiria water

QENS Data Analysis in Mantid Energy Moments

QENS Data Analysis in Mantid Energy Moments

QENS Data Analysis in Mantid Absorption Corrections Container subtractions

QENS on Organic Photovoltaic Materials Organic solar cell PCBM Analysis shows that the melting of this material is entirely driven by its tail motions

QENS Experiment to design solid acid catalyst Diffusion modes of cyclohexanone oxime passing through a pore with active sites (red), Top: Smooth Fickian diffusion means the oxime diffuses straight down the pore. Bottom: Jump diffusion sees the oxime move between active sites with a specific residence time. ME Potter, et al. ACS Catalysis 7 2926 -2934 (2017) The Q dependence of the HWHM of the Lorentzian for Zeolite-Y (left) and SAPO-37 (right) obtained from QENS experiment on OSIRIS

QENS Experiment to Understand Plastic Phase FABADA is used to fit QENS data obtained from IRIS instrument at ISIS. There is no gain by using L=3 over L=2 for this QENS fitting

QENS Experiment on Single Particle Dynamics from Molten Salts OSIRIS Experiment is compared with DFT-MD

High throughput QENS Data reduction and preliminary analysis Mantid Algorithms: • Indirect. Quick. Run/Energy. Window. Scan • SOf. QWMoment. Scan • Indirect. Sample. Changer All these algorithms will be integrated with FABADA to be used in future for high throughput analysis

Summary • Most of the functionality of QENS data analysis is available in Mantid • Bayesian analysis is useful to analyse complicated data consists of several overlapping peaks, backgrounds and spurions. • Further improvements are necessary for high throughput QENS analysis, more functions for modelfitting and where incoherent approximations don’t valid.

Acknowledgements • • • Spencer Howell Dereck Tendachi Kachere Samuel Jackson Dan Nixon Elliot Oram Louise Mc. Cann Bartomeu Llopis Vidal Diego Monserat Luis Carlos Pardo Felix Fernandez-Alonso • Universitat Polit`ecnica de Catalunya and the UK Science & Technology Facilities Council for their continued support of this collaborative work • Mantid team at ISIS for helping the implementation • Friendly Users group of Molecular Spectroscopy for testing all implementation patiently Thank you for your attention !