Pair distribution function study on compression of liquid gallium
- Los Alamos National Laboratory
- SUNY-SB
Integrating a hydrothermal diamond anvil cell (HDAC) and focused high energy x-ray beam from the superconductor wiggler X17 beamline at the National Synchrotron Light Source (NSLS) at the Brookhaven National Laboratory (BNL), we have successfully collected high quality total x-ray scattering data of liquid gallium. The experiments were conducted at a pressure range from 0.1GPa up to 2GPa at ambient temperature. For the first time, pair distribution functions (PDF) for liquid gallium at high pressure were derived up to 10 {angstrom}. Liquid gallium structure has been studied by x-ray absorption (Di Cicco & Filipponi, 1993; Wei et al., 2000; Comez et al., 2001), x-ray diffraction studies (Waseda & Suzuki, 1972), and molecular dynamics simulation (Tsay, 1993; Hui et al., 2002). These previous reports have focused on the 1st nearest neighbor structure, which tells us little about the atomic arrangement outside the first shell in non- crystalline materials. This study focuses on the structure of liquid gallium and the atomic structure change due to compression. The PDF results show that the observed atomic distance of the first nearest neighbor at 2.78 {angstrom} (first G(r) peak and its shoulder at the higher Q position) is consistent with previous studies by x-ray absorption (2.76 {angstrom}, Comez et al., 2001). We have also observed that the first nearest neighbor peak position did not change with pressure increasing, while the farther peaks positions in the intermediate distance range decreased with pressure increasing. This leads to a conclusion of the possible existence of 'locally rigid units' in the liquid. With the addition of reverse Monte Carlo modeling, we have observed that the coordination number in the local rigit unit increases with pressure. The bulk modulus of liquid gallium derived from the volume compression curve at ambient temperature (300K) is 12.1(6) GPa.
- Research Organization:
- Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC52-06NA25396
- OSTI ID:
- 960940
- Report Number(s):
- LA-UR-08-06660; LA-UR-08-6660; PRLTAO; TRN: US1002674
- Journal Information:
- Physical Review Letters, Journal Name: Physical Review Letters; ISSN 0031-9007
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ABSORPTION
AMBIENT TEMPERATURE
AUGMENTATION
BEAMS
BNL
COMPRESSION
COORDINATION NUMBER
DATA
DIAGRAMS
DIAMONDS
DISTANCE
DISTRIBUTION FUNCTIONS
DYNAMICS
ENERGY
GALLIUM
LIQUIDS
MATERIALS
NSLS
PEAKS
PRESSURE RANGE
PRESSURE RANGE MEGA PA 10-100
SCATTERING
SHELLS
SIMULATION
SUPERCONDUCTORS
X-RAY DIFFRACTION