Modeliranje vode s potencialom vrtnice

Tušek, Martin (author), Lukšič, Miha (mentor)

Z lastnim računalniškim programom za simulacijo Monte Carlo v NpT ansamblu sem preučeval strukturne in termodinamske lastnosti preprostega dvodimenzionalnega modela vode z enim interakcijskim mestom. Eno samo kotno prostostno stopnjo, s katero opišemo vodikovo vez med dvema molekulama vode, so predstavljale sinusoidne krivulje iz družine vrtnic. V delu sem uporabljal trilistno krivuljo oblike sin(3θ) po kateri je model dobil ime »model vode s potencialom vrtnice«. V primerjavi s sorodnim 2D Mercdes-Benzovim (MB) modelom, ki ima štiri interakcijska mesta, je model vode s potencialom vrtnice zaradi manjšega števila interakcijskih mest med sosednjimi molekulami vode računsko bolj učinkovit. Z ustrezno izbiro parametrov modela dobimo dobro skladanje z MB modelom vode: model je strukturno podoben MB vodi in kaže kvalitativno enake za vodo značilne anomalne lastnosti. V delu bo predstavljen vpliv parametrov modela in temperature na potek parske porazdelitvene funkcije ter temperaturna odvisnost gostote, toplotne kapacitete, izotermne stisljivost in koeficienta toplotnega raztezka. Izbrane termodinamske količine in parska porazdelitvena funkcija pri različnih temperaturah bodo primerjane z rezultati MB modela.

• Language: Slovenian
• Keywords: simulacija Monte Carlo, model vode s potencialom vrtnice, parska porazdelitvena funkcija, gostota, toplotna kapaciteta, izotermna stisljivost, koeficient temperaturnega raztezka
• Work type: Bachelor thesis/paper
• Typology: 2.11 - Undergraduate Thesis
• Organization: FKKT - Faculty of Chemistry and Chemical Technology
• Year: 2019
• PID: 20.500.12556/RUL-109544
• COBISS.SI-ID: 1538315459
• Publication date in RUL: 05.09.2019

TUŠEK, Martin, 2019, Modeliranje vode s potencialom vrtnice [online]. Bachelor’s thesis. [Accessed 11 April 2025]. Retrieved from: https://repozitorij.uni-lj.si/IzpisGradiva.php?lang=eng&id=109544

Secondary language

• Language: English

Abstract

Using my own computer program for Monte Carlo simulation in NpT ensemble, I explored structural and thermodynamic properties of a simple two-dimensional single-point water model. A single angular degree of freedom, describing the hydrogen bonding between two water molecules, is accounted for through sinusoidal rose curves. A 3-petal curve of the general form sin(3θ) was used and the model was therefore named rose water. Compared to its analogue, i.e. a four-site 2D Mercedes Benz (MB) model, the rose water is computationally more efficient due to the resulting decrease in the number of pairwise interaction sites between neighbouring waters. Proper selection of model’s potential parameters gives good agreement with the MB water model: it is structurally similar to MB water and exhibits qualitatively same water-like anomalous behaviour. The work will present the effect of model’s parameters and temperature on pair distribution function, as well as temperature dependence of density, isothermal compressibility, coefficient of thermal expansion, and heat capacity. Selected thermodynamic properties and pair distribution function will be compared to the results of MB model for various temperatures.

• Keywords: Monte Carlo simulation, rose-water model, pair distribution function, density, heat capacity, isothermal compressibility, coefficient of thermal expansion