TY - JOUR
T1 - Model colloidal fluid with competing interactions
T2 - Bulk and interfacial properties
AU - Archer, A. J.
AU - Pini, D.
AU - Evans, R.
AU - Reatto, L.
PY - 2007
Y1 - 2007
N2 - Using a simple mean field density functional theory (DFT), the authors investigate the structure and phase behavior of a model colloidal fluid composed of particles interacting via a pair potential which has a hard core of diameter, is attractive Yukawa at intermediate separations, and is repulsive Yukawa at large separations. The authors analyze the form of the asymptotic decay of the bulk fluid correlation functions, comparing results from DFT with those from the self-consistent Ornstein-Zernike approximation (SCOZA). In both theories the authors find rich crossover behavior, whereby the ultimate decay of correlation functions changes from monotonic to long wavelength damped oscillatory decay on crossing certain lines in the phase diagram or sometimes from oscillatory to oscillatory with a longer wavelength. For some choices of potential parameters the authors find, within the DFT, a λ line at which the fluid becomes unstable with respect to periodic density fluctuations. SCOZA fails to yield solutions for state points near such a λ line. The propensity towards clustering of particles, which is reflected by the presence of a long wavelength () slowly decaying oscillatory pair correlation function, and a structure factor that exhibits a very sharp maximum at small but nonzero wave numbers, is enhanced in states near the λ line. The authors present density profiles for the planar liquid-gas interface and for fluids adsorbed at a planar hard wall. The presence of a nearby λ transition gives rise to pronounced long wavelength oscillations in the one-body density profiles at both types of interface.
AB - Using a simple mean field density functional theory (DFT), the authors investigate the structure and phase behavior of a model colloidal fluid composed of particles interacting via a pair potential which has a hard core of diameter, is attractive Yukawa at intermediate separations, and is repulsive Yukawa at large separations. The authors analyze the form of the asymptotic decay of the bulk fluid correlation functions, comparing results from DFT with those from the self-consistent Ornstein-Zernike approximation (SCOZA). In both theories the authors find rich crossover behavior, whereby the ultimate decay of correlation functions changes from monotonic to long wavelength damped oscillatory decay on crossing certain lines in the phase diagram or sometimes from oscillatory to oscillatory with a longer wavelength. For some choices of potential parameters the authors find, within the DFT, a λ line at which the fluid becomes unstable with respect to periodic density fluctuations. SCOZA fails to yield solutions for state points near such a λ line. The propensity towards clustering of particles, which is reflected by the presence of a long wavelength () slowly decaying oscillatory pair correlation function, and a structure factor that exhibits a very sharp maximum at small but nonzero wave numbers, is enhanced in states near the λ line. The authors present density profiles for the planar liquid-gas interface and for fluids adsorbed at a planar hard wall. The presence of a nearby λ transition gives rise to pronounced long wavelength oscillations in the one-body density profiles at both types of interface.
UR - http://www.scopus.com/inward/record.url?scp=33846071564&partnerID=8YFLogxK
U2 - 10.1063/1.2405355
DO - 10.1063/1.2405355
M3 - Article (Academic Journal)
C2 - 17212487
AN - SCOPUS:33846071564
SN - 0021-9606
VL - 126
JO - Journal of Chemical Physics
JF - Journal of Chemical Physics
IS - 1
M1 - 014104
ER -