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Novel states of matter and new chemistry. Panel chairs: Andrew Cornelius, Dana Dattelbaum Panelists: Valentin Iota Yue Meng Artem Oganov Maddury Somayazulu ( Choong-shik Yoo ). Status: Identified 3 PRDs Outlined s cientific and technical challenges High impact topics

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novel states of matter and new chemistry
Novel states of matter and new chemistry
  • Panel chairs: Andrew Cornelius, Dana Dattelbaum
  • Panelists:
      • Valentin Iota
      • YueMeng
      • ArtemOganov
      • MaddurySomayazulu
      • (Choong-shikYoo)
  • Status:
  • Identified 3 PRDs
  • Outlined scientific and technical challenges
  • High impact topics
  • Potential Sidebars
  • HPCAT “want list”
hpcat looking forward

From discovery to prediction: new paradigms in extreme condition chemistry

  • Enormous potential for substantially different (improved) materials
  • Rich chemistry waiting to be explored with the diamond cell
  • Foundational understanding of how chemical bonds and electrons behave in extreme conditions

HPCAT: Looking Forward

  • “Throwing periodic table out” – defining new rules at extreme conditions
  • Unprecedented bonding in “inert” atomic or molecular species
    • Unusual Xe-halogen extended structures
    • Stability of hydrogen coordination and hydrogen bond symmetrization
    • Van der Waals and ionic compounds
  • “Metallic” behavior
    • “Holy grail” – metallic hydrogen, > 4 Mbar, (2 Mbar, high temperature)
    • Superconductivity P/T thresholds, metallic-to-insulator transitions at even high pressures
  • Polymeric structures – conducting polymers (removing defects), high energy density materials (cg-N, p-CO)
  • New hydrides (low pressures < 2 GPa, micro-reactors, in-situ reactions)
  • Ultrahard materials – carbon clusters (b-CN), boron compounds
  • Shock-driven chemistry – reaction evolution at 20-50 GPa, 2000-4000K, ns timescales
slide3

HPCAT: Looking Forward

From discovery to prediction: new paradigms in extreme condition chemistry

Scientific challenges

  • New definitions of chemical reactivity – define “rules” and exploit them
  • Prediction of novel structures and properties – integration of theory and experiment to predict phases and their properties
  • Accessing and diagnosing new phase space with multiple in-situ probes – includes P, T, strain rate, B/e fields, combined static/shock/ramp compression paths
  • Exploiting metastabilitiesfor synthesis (theory-guided, recovery)
  • Having the right “probe” at the right state – XRD, spectroscopy, resistivity
    • Tunability of probes
    • Design of experiments – conclusively prove/disprove, beyond APS = x-rays, lab = other
    • What details should be measured to compare to theory?
    • Robustness of technique with user model (level of development, sophistication)
  • O(N3) and exponential scaling, limitations on periodicity and # atoms
  • Cumbersome computations of energy landscapes (potentials/transition states) in extremes, computational limitations on dynamics (ps), roles of excited states
hpcat looking forward1

In-situ, in real time (smaller, faster): defining the details of chemical transformations in extreme conditions

  • Chemistry is the study of structure and bonding changes going beyond static properties and stable structures
  • Major future direction must be time-resolved measurements for following chemical reaction mechanisms and their kinetics in extreme conditions

HPCAT: Looking Forward

  • Competitions between kinetic vs. thermodynamic paths – exploiting potential surfaces, to obtain new products
  • Time-resolved diffraction techniques using synchrotron pulse sequence and fast detectors focused on structure and bonding changes
    • Thermal expansion under pulsed laser heating
    • Phase transformations under intermediate strain rate compression
    • Phases involved in combustion
  • Unravel long-standing challenges dynamic compression – pathways through phase diagrams, kinetics in melting/freezing, incomplete transformations/phase hysteresis/retained phases, on-set vs. completion of chemistry
  • New combinations of dynamic loading paths to reach new phase space– shocking, ramping, fast heating from static states
science scope fundamental time scale
Science Scope-- Fundamental Time Scale

3rd Generation

Synchrotron Source

APS, Spring8, ESRF

4th Generation

Light Source

APS upgrade plan

Femtosecond

Picosecond

Nanosecond

Microsecond

Molecular Vibration

Inner-Shell Decay

Molecular Rotation

Radioactive Decay

Solvation Dynamics

Energy Transfer in Photosynthesis

Electron Transfer in Photosynthesis

Non-Thermal Melting & Phase Transitions

Spin Dynamics

Optical & Acoustic Phonon

Thermal Melting

Strain Propagation

Spatial Resolution

10-9

10-12

10-15

10-6

Sub-micron/Micron

Nanometer

slide6

HPCAT: Looking Forward

In-situ, in real time (smaller, faster): defining the details of chemical transformations in extreme conditions

Scientific challenges

  • Kinetic vs. thermodynamic control of reaction pathways and products
  • Following and interpreting chemical bonding changes in extreme conditions in real-time
  • Simultaneous probes on sample: XRD, x-ray (ex. XANES) and optical spectroscopies, electronic properties – having the “right” probe, beam sizes, containment of reactive species in DACs
  • Theory-experiment comparison- limitations on temporal dynamics of simulations – sub-ns
  • Bridging the “strain rate gap,” and linking static to dynamic processes – new techniques and diagnostics
slide7

HPCAT: Looking Forward

Photon-induced chemical reactions

  • Photons (optical, x-rays) can drive unique chemical bonding changes due to different selection rules and surmounting activation barriers
  • Challenge to bring prediction and control to x-ray induced chemistry

Mixture of N2/O2(34% N2)

  • Examples:
    • Radiation-splitting of H2O – Mao
    • Using radiation to make new materials – Meng
    • Explosives decomposition (PETN), generating gases in-situ
    • “Traditional photochemistry” in extremes

1.5 GPa

0.5 GPa

Decomposition

Reaction

NO2+NO3-, an ionic phase of

N2O5 after x-ray radiation of

the N2/O2 mixture

A know phase previously found

Only at low temperatures

NO+NO3- at 1.7 GPa

after x-ray radiation of

NO2+NO3- at 2 GPa

for 12 hours

A new phase

Y. Meng et al, Physical Review B (2006)

slide8

HPCAT: Looking Forward

From discovery to prediction: new paradigms in extreme condition chemistry

Scientific challenges

  • Controlof photo-induced chemical reactions at multiple wavelengths and conditions (P,T) – designing new materials
  • Means of producing new materials
  • Multi-wavelength experiments – pump to drive chemistry, x-rays to probe or vice versa
  • High repetition rate experiments - Laser shock drives, photoactive reactions (outside DACs)
  • Electron dynamics in extremes (photophysics) – alteration of excited state manifolds under high P/T/strain rate conditions
  • Avoiding photon-damage – incorporating active filtering at beamlines, knowing what state your sample is in, etc.
slide9

HPCAT: Looking Forward

Overarching Technicalchallenges

Beam characteristics

  • Flux (per pulse), detector technology, data management and analysis
  • (sub)micron- and variable size beams, improved beam focusing, high resolution energy selectivity
  • Adapting to diamond cell – better diffraction techniques (reliable intensity information, in situ references, micron control of sample position (incl. off-line) and rotation), single crystals, amorphous scattering
  • Pulse-to-pulse variation, correct for beam characteristics (intensity, detector efficiency), efficient through-put of pump-probe experiments
slide10

HPCAT: Looking Forward

Overarching Technicalchallenges

Sample improvements

  • Achieving exquisite compositional control, can we redesign sample loading methods, micro-reactors
  • Larger volumes to higher pressures – necessary for recovery, neutron diffraction, trade-off with time duration?, adapting probes and laser heating for larger volumes (variable laser spot size- unique to HP-CAT)
  • Mixed phases – probing uniform or non-uniform structures
slide11

HPCAT: Looking Forward

Overarching Technicalchallenges

Theory advances

  • Achieving “linear” scaling – moving to larger atom simulations with enough detail to believe predicted properties/behaviors
  • Simulating mixed compositions, amorphous/crystalline structures
  • Predicting synthesis paths – design experiments
slide12

HPCAT: Looking Forward

Sidebar topics

  • Novel Xe chemistry (Zulu)
  • Theoretical predictions of novel structures (Oganov)
  • Radiation-induced chemistry (Meng and Pravica)
  • Detonation chemistry (Dattelbaum)
slide13

HPCAT: Looking Forward

HP-CAT “want list” – next 10 yrs

  • “Center concept” with DCS
    • High priority – theory team (4 pp) providing collaboration and support to users
    • In-house crystallographer
    • Should include APS theory/crystallography staff
    • Diverse expertise- chemistry, materials science, physics
    • Possible joint positions (between HP-CAT and DCS, APS-external)
  • Move toward time-resolved measurements: Fast “pumps” for pump-probe – short pulse laser heating, laser-based compression, dynamic DACs, timed to detectors and bunch sequences
  • Detector development – Pilatus 1M, creative ways of getting multiple frames – multiple CCDs, streaking images (chopper etc.), flux limitations, coordination and scheduling of time-resolved exp’ts due to set-up time
  • More diagnostics - combinations of “on-line” probes, more off-line capabilities (infrared, absorption, optical pump-probe?), space is an issue – external building(s), walking distance
  • Sample preparation improvements – glovebox (in process), gas loading - mixtures, micro-machining (laser), micromanipulators, cryogenic loading
  • Sample and beam alignment – sub-micron beams, precision control, switchable and tunable filters to prevent beam damage, visualization of sample on table, creative ways of getting multiple beams on sample