Prediction of Radon-222 Phase Behavior by Monte Carlo Simulation

Abstract

Histogram-reweighting Monte Carlo simulations in the grand canonical ensemble are used to determine saturated liquid and vapor densities, vapor pressures, heats of vaporization, and compressibility factors for radon-222 from the normal boiling point to the critical point. An optimized intermolecular potential is developed by fitting parameters to reproduce experimental vapor pressures and the critical temperature. Vapor pressures are reproduced by simulation to within 2.2% of experiment, while the critical temperature and normal boiling point are reproduced exactly within the combined uncertainty of simulation and experimental data. The predictions of simulation are used to evaluate the reliability of reported experimental liquid densities, and those predicted by equations of state. While the predictions of simulation are in agreement with equations of state for the liquid density, significant differences are observed between the predictions of simulation and experiment. These results suggest that previously reported experimental liquid densities for radon-222 may be erroneous.

Henry’s Law Constant of Noble Gases in Water, Methanol, Ethanol, and Isopropanol by Experiment and Molecular Simulation

“…xenon nd don @nA in the pure solvents wter @r 2 yAD methnol @weyrAD ethnol @ityrA nd propnEPEol in systemti wyF usequentlyD the simultion results re disussed nd ompred with the experimentl vlues of this work nd from the litertureD where it is shown tht the predited renry9s lw onstnt dt re onsistent over wide temperture rnge nd signi(ntly extend the dtse for PR soluteEsolvent pirsF Experiments qs soluility mesurements were onduted with n pprtus tht ws initilly desried y indmnn et lF 14 nd ws susequently employed y our group to study vrious mixE turesF 10,11,15 e detiled desription of the mesuring proedure ws presented in these puE litions so tht only its si priniples re outlined hereF he syntheti method ws usedD whih mens tht the msses of the pure omponents loded into the mesuring ell were preisely determinedD leding to the mole frtion of the inry mixtureF he vporEliquid equilirium t spei(ed temperture ws rehed y omposing mixture where only negligily smll vpor ule remins in the liquid phseD whih represents stte on the sturted liquid lineF gonsequentlyD the mesured pressure in the ell t this stte point is Experimental uncertainties ltinum resistne thermometers with si resistne of IHH Ω were used for the temE perture mesurements tht led to stndrd unertinty of u T ¦ 0.04 uF he pressure in the mesuring ell ws determined with pressure trnsduer from roneywell est 8 wesurement @model uper tiA tht hd mesuring sle of UH w nd n ury of HFI7 of the full sle so tht the stndrd unertinty of the phse equilirium pressure ws u p¦ 0.07 wF ressure trnsduers of the sme type were employed to determine the quntities of the pure omponents tht were loded into the ellF roweverD for the gseous omponent inletD the mesuring sle of the pressure trnsduer ws PH w for experiE ments with neon nd IFQ w for experiments with krypton nd xenonD while for the liquid omponent inletD pressure trnsduer with mesuring sle of IHH w ws employedF sn ddition to the unertinties of the temperture nd pressure mesurementsD the unerE tinties of the equtions of stte @iyAD 1618 tht were used to lulte the density of the pure omponentsD hd to e onsidered to determine the unertinty of the mount of the R solute nd solventD iFeF u n gas ¦ nd u n liq ¦D respetivelyF fsed on these dtD the stndrd unertinty of the solute mole frtion u x gas ¦ ws lulted with the error propgtion lw…”

“…Statistical uncertainties are denoted by δH i . Henry's law constant data from molecular simulation for noble gases in propan-2ol, employing molecular force eld models for the solutes from Vrabec et al,9 Mick et al10 and this work. Statistical uncertainties are denoted by δH i .…”

“…he preise knowledge of phse equilirium ehvior is essentil for the design of numerous hemil engineering pplitionsD suh s distilltionD pervportionD E nd desorptionF 1,2 ispeilly phse equilirium dt of mixtures re ruil for the industry nd the suessful implementtion of vrious reserh projetsD 3,4 ut re often not ville for the relevnt systemsF gonsequentlyD further investigtion of these properties is neessry to inrese the opertionl rnge of existing pplitions s well s for the development of innovtive produts nd proessesF 5 sn this wyD resoures n e svedD supporting sustinle tretE ment of the environmentF sn this ontextD growing interest in the utiliztion of nole gses in tehnil pplitions n e oserved euse of their hemil inertnessD ut lso due to their unique physil properties tht llow for their usge in eletronis nd espeilly in the (eld of lightingF 6 woreoverD in onjuntion with nonEtoxiityD these hrteristis led to n inresing interest for the use of nole gses in mediine nd phrmeutisF 7 por mny pplitionsD the soluility of nole gses in liquidsD whih n e desried y mens of renry9s lwD 8 is of prtiulr interestF 9 roweverD gs soluility dt for relevnt solvents hve only een reported for limited temperture rngeF sn preeding pulitions of our groupD 10,11 renry9s lw onstnt dt for the solutes helium @reA nd rgon @erA in propnEPEol @PEryrA were determined over temperture rnge from PSR to RVP u y experiment nd moleulr simultionF hese experiments were ontinued in the present workD onsidering neon @xeAD krypton @urA nd xenon @eA in…”

“…where ρ s is the sturted liquid density of the solventD T the temperture nd k B foltzmnn9s onstntF o smple stte of in(nite dilutionD simultions of pure solvents were onduted in the N pT ensemleD while the solutes were only inserted s test prtiles with idom9s 8 Vrabec et al 9 and Mick et al 10 Statistical uncertainties are denoted by δH i . Table S 6: Henry's law constant data from molecular simulation for noble gases in ethanol, employing molecular force eld models for the solutes from Vrabec et al, 9 Mick et al 10…”

Molecular exchange Monte Carlo: A generalized method for identity exchanges in grand canonical Monte Carlo simulations

“…where , , and are the separation, well depth, and collision diameter, respectively, for Mie potential has been optimized for noble gases [72,73], linear and branched alkane [9,54], n-alkyne [74]. All non-bonded parameters used in this work are listed in Table S1.…”