TY  - JOUR
AU  - Pipich, Vitaliy
AU  - Schwahn, Dietmar
TI  - Polymorphic phase transition in liquid and supercritical carbon dioxide
JO  - Scientific reports
VL  - 10
IS  - 1
SN  - 2045-2322
CY  - [London]
PB  - Macmillan Publishers Limited, part of Springer Nature
M1  - FZJ-2020-02316
SP  - 11861
PY  - 2020
AB  - We present experiments on molecular density fluctuations in liquid and supercritical (SC) CO2 using small-angle neutron scattering. Thermal density fluctuations in SC-CO2 determine susceptibility and correlation length identifying the Widom line at their maxima. Droplet formation occurs at the gas–liquid line and between 20 and 60 bar above the Widom line, the corresponding borderline identified as the Frenkel line. The droplets start to form spheres of constant radius of ≈ 45 Å and transform into rods and globules at higher pressure. Droplet formation represents a liquid–liquid (polymorphic) phase transition of the same composition but different density, whose difference defines its order parameter. Polymorphism in CO2 is a new observation stimulating interesting discussions on the topics of gas-like to liquid-like transition in SC fluids and polymorphism since CO2 represents a “simple” van der Waals liquid in contrast to water, which is the most widely studied liquid showing polymorphism in its supercooled state.
LB  - PUB:(DE-HGF)16
C6  - 32681012
UR  - <Go to ISI:>//WOS:000549998300003
DO  - DOI:10.1038/s41598-020-68451-y
UR  - https://juser.fz-juelich.de/record/877601
ER  -