TY - JOUR
T1 - Partial molar volume and solvation structure of naphthalene in supercritical carbon dioxide
T2 - A Monte Carlo simulation study
AU - Stubbs, John M.
AU - Drake-Wilhelm, Dylan D.
AU - Siepmann, J. Ilja
PY - 2005/10/27
Y1 - 2005/10/27
N2 - Monte Carlo simulations were used to investigate the solvation of naphthalene in supercritical carbon dioxide at a temperature of 308.38 K just above the solvent's critical temperature and at pressures of 74.6, 79.7, 87.8, and 310.2 bar covering a range from just below to far above the solvent's critical pressure and at a slightly elevated temperature of 318.15 K and a pressure of 93.0 bar. The Monte Carlo simulations were carried out in the isobaric-isothermal ensemble and employed the transferable potentials for phase equilibria (TraPPE) force field. Systems containing 2000 carbon dioxide molecules and from 0 to 4 solute molecules were used for all five state points, and additional simulations with 16 000 solvent molecules were carried out at the lower temperature and p = 79.7 bar. In agreement with experiment, the simulations yield large, negative partial molar volumes of naphthalene near the critical pressure at 79.7 bar, with values of -4340± 750 and -3400 ± 620 cm 3 mol -1 for the 2000 and 16 000 molecule systems, respectively. Structural analysis through radial distribution functions and the corresponding number integrals yields good agreement with neutron diffraction data and shows evidence for a long-range density enhancement around solutes but lacking any specific solute-solvent clustering. Solvatochromic shifts estimated from the local solvent structure correlate well with the experimental data over the entire pressure range.
AB - Monte Carlo simulations were used to investigate the solvation of naphthalene in supercritical carbon dioxide at a temperature of 308.38 K just above the solvent's critical temperature and at pressures of 74.6, 79.7, 87.8, and 310.2 bar covering a range from just below to far above the solvent's critical pressure and at a slightly elevated temperature of 318.15 K and a pressure of 93.0 bar. The Monte Carlo simulations were carried out in the isobaric-isothermal ensemble and employed the transferable potentials for phase equilibria (TraPPE) force field. Systems containing 2000 carbon dioxide molecules and from 0 to 4 solute molecules were used for all five state points, and additional simulations with 16 000 solvent molecules were carried out at the lower temperature and p = 79.7 bar. In agreement with experiment, the simulations yield large, negative partial molar volumes of naphthalene near the critical pressure at 79.7 bar, with values of -4340± 750 and -3400 ± 620 cm 3 mol -1 for the 2000 and 16 000 molecule systems, respectively. Structural analysis through radial distribution functions and the corresponding number integrals yields good agreement with neutron diffraction data and shows evidence for a long-range density enhancement around solutes but lacking any specific solute-solvent clustering. Solvatochromic shifts estimated from the local solvent structure correlate well with the experimental data over the entire pressure range.
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U2 - 10.1021/jp0502656
DO - 10.1021/jp0502656
M3 - Article
C2 - 16853571
AN - SCOPUS:27744470587
SN - 1520-6106
VL - 109
SP - 19885
EP - 19892
JO - Journal of Physical Chemistry B
JF - Journal of Physical Chemistry B
IS - 42
ER -