Skip to main content
Home

Navigation Menu

  • Back
  • About
    • Back
    • About

      Contact Us

      Business Address
      5241 Broad Branch Rd. NW

      Washington , DC 20015
      United States place Map
      Call Us (202) 387-640
    • Who We Are
      • Back
      • Leadership
      • Board & Advisory Committee
      • Initiatives
      • Financial Stewardship
      • Awards & Accolades
      • History
    • Connect with Us
      • Back
      • Outreach & Education
      • Newsletter
      • Yearbook
    • Working at Carnegie

    Contact Us

    Business Address
    5241 Broad Branch Rd. NW

    Washington , DC 20015
    United States place Map
    Call Us (202) 387-6400
  • Research
    • Back
    • Research Areas & Topics
    • Research Areas & Topics
      • Back
      • Research Areas
      • From genomes to ecosystems and from planets to the cosmos, Carnegie Science is an incubator for cutting-edge, interdisciplinary research.
      • Astronomy & Astrophysics
        • Back
        • Astronomy & Astrophysics
        • Astrophysical Theory
        • Cosmology
        • Distant Galaxies
        • Milky Way & Stellar Evolution
        • Planet Formation & Evolution
        • Solar System & Exoplanets
        • Telescope Instrumentation
        • Transient & Compact Objects
      • Earth Science
        • Back
        • Earth Science
        • Experimental Petrology
        • Geochemistry
        • Geophysics & Geodynamics
        • Mineralogy & Mineral Physics
      • Ecology
        • Back
        • Ecology
        • Atmospheric Science & Energy
        • Adaptation to Climate Change
        • Water Quality & Scarcity
      • Genetics & Developmental Biology
        • Back
        • Genetics & Developmental Biology
        • Adaptation to Climate Change
        • Developmental Biology & Human Health
        • Genomics
        • Model Organism Development
        • Nested Ecosystems
        • Symbiosis
      • Matter at Extreme States
        • Back
        • Matter at Extreme States
        • Extreme Environments
        • Extreme Materials
        • Mineralogy & Mineral Physics
      • Planetary Science
        • Back
        • Planetary Science
        • Astrobiology
        • Cosmochemistry
        • Mineralogy & Mineral Physics
        • Planet Formation & Evolution
        • Solar System & Exoplanets
      • Plant Science
        • Back
        • Plant Science
        • Adaptation to Climate Change
        • Nested Ecosystems
        • Photosynthesis
        • Symbiosis
    • Divisions
      • Back
      • Divisions
      • Biosphere Sciences & Engineering
        • Back
        • Biosphere Sciences & Engineering
        • About

          Contact Us

          Business Address
          5241 Broad Branch Rd. NW

          Washington , DC 20015
          United States place Map
          Call Us (202) 387-640
        • Research
        • Culture
        • Path to Pasadena
      • Earth & Planets Laboratory
        • Back
        • Earth & Planets Laboratory
        • About

          Contact Us

          Business Address
          5241 Broad Branch Rd. NW

          Washington , DC 20015
          United States place Map
          Call Us (202) 387-640
        • Research
        • Culture
        • Campus
      • Observatories
        • Back
        • Observatories
        • About

          Contact Us

          Business Address
          5241 Broad Branch Rd. NW

          Washington , DC 20015
          United States place Map
          Call Us (202) 387-640
        • Research
        • Culture
        • Campus
    • Instrumentation
      • Back
      • Instrumentation
      • Our Telescopes
        • Back
        • Our Telescopes
        • Magellan Telescopes
        • Swope Telescope
        • du Pont Telescope
      • Observatories Machine Shop
      • EPL Research Facilities
      • EPL Machine Shop
      • Mass Spectrometry Facility
      • Advanced Imaging Facility
  • People
    • Back
    • People
      Observatory Staff

      Featured Staff Member

      Staff Member

      Staff Member

      Professional Title

      Learn More
      Observatory Staff

      Search For

    • Search All People
      • Back
      • Staff Scientists
      • Leadership
      • Biosphere Science & Engineering People
      • Earth & Planets Laboratory People
      • Observatories People
    Observatory Staff
    Dr. Allan Spradling
    Staff Scientist, Emeritus Director

    Featured Staff Member

    Allan Spradling portait

    Dr. Allan Spradling - HHMI

    Staff Scientist, Emeritus Director

    Learn More
    Observatory Staff
    Dr. Allan Spradling
    Staff Scientist, Emeritus Director

    Allan Spradling and his team focus on the biology of reproduction, particularly oogenesis — the process of egg formation.

    Search For

    Search All Staff
  • Events
    • Back
    • Events
    • Search All Events
      • Back
      • Biosphere Science & Engineering Events
      • Earth & Planets Laboratory Events
      • Observatories Events

    Upcoming Events

    Events

    Events

    People sit on the shore at sunset.
    Workshop

    Seventh Workshop on Trait-based Approaches to Ocean Life

    Pacific Grove, CA

    August 4

    9:00pm PDT

    A gray-true color Mercury next to a colorized Mercury that combines visible and near infrared light to highlight the differences in surface composition.
    Public Program

    Mercury beyond MESSENGER: Recent Progress from the Earth and Planets Laboratory

    Anne Pommier, Staff Scientist, EPL

    June 5

    6:30pm EDT

    brian-yurasits-EQlwRGr5sqk-unsplash.jpg
    Seminar

    Microenvironmental ecology and symbiosis

    Dr. Michael Kühl

    May 14

    11:00am PDT

  • News
    • Back
    • News
    • Search All News
      • Back
      • Biosphere Science & Engineering News
      • Earth & Planets Laboratory News
      • Observatories News
      • Carnegie Science News
    News

    Recent News

    News

    News and updates from across Carnegie Science.
    Read all News
    Vera Rubin at Carnegie Science’s former Department of Terrestrial Magnetism, now part of the Earth and Planets Laboratory, in 1972 usi
    Breaking News
    June 18, 2025

    10 Iconic Photographs of Vera Rubin

    A gray-true color Mercury next to a colorized Mercury that combines visible and near infrared light to highlight the differences in surface composition.
    Breaking News
    June 17, 2025

    Inside Mercury: What Experimental Geophysics Is Revealing About Our Strangest Planet

    Vera Rubin at Lowell Observatory, 69-inch [i.e., 72-inch] Telescope (Kent Ford in white helmet)
    Breaking News
    June 17, 2025

    Things Named After Carnegie Astronomer Vera Rubin

  • Donate
    • Back
    • Donate
      - ,

    • Make a Donation
      • Back
      • Support Scientific Research
      • The Impact of Your Gift
      • Planned Giving
    Jo Ann Eder

    I feel passionately about the power of nonprofits to bolster healthy communities.

    - Jo Ann Eder , Astronomer and Alumna

    Header Text

    Postdoctoral alumna Jo Ann Eder is committed to making the world a better place by supporting organizations, like Carnegie, that create and foster STEM learning opportunities for all. 

    Learn more arrow_forward
  • Home

Flavia Bossi

Flavia Bossi

Senior Research Associate

Plant Biology
Yang Bi

Yang Bi

Postdoctoral Fellow

Plant Biology
October 06, 2015

Carnegie’s Jonikas and Zhang Receive Prestigious NIH Awards

Portrait photo of Leslie Willoughby

Leslie Willoughby

Science Writer

Global Ecology
Kristen Salvestrini

Kristen Salvestrini

Executive Assistant

Global Ecology
Clare Tuma

Clare Tuma

Human Resources Business Partner

Biosphere Sciences & Engineering
Eddines_LaChelle

La Chelle Eddines

Executive Assistant

Global Ecology
Kelsey Foster

Kelsey Foster

Graduate Student

Global Ecology
Wu Sun

Wu Sun

Research Associate

Global Ecology
Abstract
Phase transitions and equations of state of the alkaline earth fluorides CaF2, SrF2, and BaF2 were examined by static compression to pressures as high as 146 GPa. Angle-dispersive x-ray diffraction experiments were performed on polycrystalline samples in the laser-heated diamond-anvil cell. We confirmed that at pressures less than 10 GPa all three materials undergo a phase transition from the cubic (Fm (3) over barm) fluorite structure to the orthorhombic (Pnam) cotunnite-type structure. This work has characterized an additional phase transition in CaF2 and SrF2: these materials were observed to transform to a hexagonal (P6(3)/mmc) Ni2In-type structure between 63-79 GPa and 28-29 GPa, respectively, upon laser heating. For SrF2, the Ni2In-type phase was confirmed by Rietveld refinement. Volumes were determined as a function of pressure for all high-pressure phases and fit to the third-order Birch-Murnaghan equation of state. For CaF2 and SrF2, the fluorite-cotunnite transition results in a volume decrease of 8-10 %, while the bulk modulus of the cotunnite-type phase is the same or less than that of the fluorite phase within uncertainty. For all three fluorides, the volume reduction associated with the further transition to the Ni2In-type phase is similar to 5%. The percentage increase in the bulk modulus (Delta K) across the transition is greater when the cation is smaller. While for BaF2, Delta K is 10-30 %, Delta K values for SrF2 and CaF2 are 45-65 % and 20-40 %. Although shock data for CaF2 have been interpreted to show a transition to a highly incompressible phase above 100 GPa, this is not consistent with our static equation of state data.
View Full Publication open_in_new

Pagination

  • Previous page chevron_left
  • …
  • Page 345
  • Page 346
  • Page 347
  • Page 348
  • Current page 349
  • Page 350
  • Page 351
  • Page 352
  • Page 353
  • …
  • Next page chevron_right
Subscribe to

Get the latest

Subscribe to our newsletters.

Privacy Policy
Home
  • Instagram instagram
  • Twitter twitter
  • Youtube youtube
  • Facebook facebook

Science

  • Biosphere Sciences & Engineering
  • Earth & Planets Laboratory
  • Observatories
  • Research Areas
  • Strategic Initiatives

Legal

  • Financial Statements
  • Conflict of Interest Policy
  • Privacy Policy

Careers

  • Working at Carnegie
  • Scientific and Technical Jobs
  • Postdoctoral Program
  • Administrative & Support Jobs
  • Carnegie Connect (For Employees)

Contact Us

  • Contact Administration
  • Media Contacts

Business Address

5241 Broad Branch Rd. NW

Washington, DC 20015

place Map

© Copyright Carnegie Science 2025