Inelastic Subproject Report B. Fultz, Caltech

Scope of Science in WBS 10Tasks and goals of the DANSE subprojectRelease Plans

Risks and Challenges

WBS 10: Science Scope for Inelastic Scattering

1) spin correlations in magnets, superconductors, and materials close to metal-insulator transitions

2) vibrational excitations in solids and their relationship to phase diagrams and equations of state of materials

3) tunneling and reorientation transitions of small molecules on surfaces

4) vibrational spectra of molecules or individual atoms such as hydrogen

5) diffusional motions and relaxation processes studied by quasielastic scattering

PublicationTrends

Density Functionaland Scattering

1.4x10-3

1.2

1.0

0.8

0.6

0.4

0.2

0.020062004200220001998199619941992

Year

Papers_LDAGGA_n(inelastic OR diffract*) AND (neutron OR X-ray) AND (GGA OR (LDA NOT ICE))

Papers_GGA_n(inelastic OR diffract*) AND (neutron OR X-ray) AND GGA 2006 incomplete

Roadmap of Sept. 2001

ExperimentalData

Simulation

AcyclicTransformations

Modeling

Inelastic Reduction Software

Release 1.1 • Occurred on schedule• 3,789 files, more in svn repository• 2 dozen packages, emphasis on Reduction (also simulation)• Binaries for Windows XP, Mac OS 10, Linux• Modular components - reduction framework

Release 1.2 plans:• ARCS itself (need data to try it out)• Multiphonon correction (several versions available)• Multiple scattering correction (see Max Kresch’s poster)• Detector visualization (Jiao has a demo)• September 2007 release (tentative)

Idea: Multiple Incident Energies for Higher Resolution

Simulation Framework: Jiao Lin 2007

Release in 2007

• Extensions to phonon scattering with dynamics model

• Scattering from correlation functions G(r,t) (q,E)

• Documentation

Simulation Framework (package diagram with dependencies)

Ab-Initio: Release 2007 Olivier Delaire

crystal structure

displacement generator

supercell generator

distorted supercell generator

DFT engineforce calculator

IFC calculatorBvK package

uses

uses

Takes IFC

object

based on

DFT engine

Crystal structurek-point gridaccuracy params

GS energyGS densityforces on nuclei

VASP Wien2kAbinit

crystal structure

atomsbasis vectorslattice vectors

isEquivalent()

1

Ab-Initio: Two features for 2007

Ab Initio Simulation uses

Prototype results

Experiment (Pharos) Bv-K Model (Brockhouse) VASP (mag Ni)

Chemical Physics: Brandon Keith Starts Feb. 2007

• Molecular Dynamics -- GULP• Gaussian Basis Set LDA (GAMESS, NWCHEM)• Normal Mode Analysis (CLIMAX, nMOLDYN)

API DesignData Object DesignPrioritization and release plans TBA

Plans for 2008

• Chemical Physics

• Magnetic scattering (magnon models)

• Single crystals using UB matrix

• Fits to noisy dispersive information

• Separation of phonons and magnons by Q-dependence

• Neutron weight correction (prototypes in use now)

• SEQUOIA and CNCS (TBA)

• Black absorber

Education and Outreach

• Textbooks

• Students- J. Munoz, U. Texas El Paso, underrepresented minority student- Eliot Setzer, Caltech CS undergraduate- M. Kresch, Chen Li, Caltech graduate students

Inelastic Effort Today

• Fully staffed- Jiao Lin- Olivier Delaire- Brandon Keith- Max Kresch (grad student)

• Working to find science niches for everyone, consistent with project tasks

• Close feedback to DANSE management on practices

Risks (and Opportunities)

• Direction in magnetic scattering -- requires real science, funds, beamtime.

• Direction in chemical physics -- requires real science, funds, beamtime.

• Robustness of fitting dispersive information in noisy data -- ideas may change as source power increases at SNS.

• Some legacy code is not documented well, but may need new functionality.

• Microsoft Windows and user expectations.• User science expertise needs to be high for some applications. • How do we support users?• Life may get dull for developers.

Reasons for Confidence and Optimism

• Most of the large science packages have been tested.

• Prototypes have been tested for many of the 5-year deliverables.

• Software development process becoming more agile.

• Staff skills are international-class.

Summary of WBS 10: Inelastic Scattering

1) Scope for:- dynamics of small molecules- elementary excitations in solids

2) Reduction application is mature. Plans for Release 1.2.

3) Prototypes exist for many of the main deliverables, and parts of many others have been tried.

4) Staff in place for all scope.

5) Nearly all functionality can be available in some form in 2008.