Molecular Dynamics Simulations of Liquid Systems Saturated with Gas

The temperature dependence of the solubility of a gas in a liquid is very important in many industrial and naturally-occurring processes. Examples include carbonylation and hydrogenation processes that take place in bulk liquid and the dissolution of O2 and CO2 in seawater. Whereas some gases have a solubility which decreases with increasing temperature others have the opposite temperature dependence in the same liquid. For example, experimental measurements carried out in this department have found that the solubility of ethene in mixtures of methanol and methyl propanoate decreases with increasing temperature whereas CO exhibits the opposite trend. Initial explanations of this difference were based on entropy arguments but this is very difficult to corroborate experimentally. An alternative approach to explain this behaviour and to gain physical insight is to simulate the dissolution process using molecular dynamics. Preliminary simulations suggest that CO sits in a persistent cage formed by clusters of methanol and methyl propanoate that are linked together by hydrogen bonding.

The PhD project will involve the use of molecular dynamics simulations of liquid systems saturated with gas in order to understand in detail why some gases have positive, while others have negative, temperature dependence of solubility.

The student will be supervised by Dr John Satherley and Dr David Cooper in the Department of Chemistry at the University of Liverpool, http://www.liverpool.ac.uk/chemistry, and co-supervised by Dr Yong Chin and Dr Ilian Todorov from the Computational Chemistry Group at STFC Daresbury Laboratory, http://www.stfc.ac.uk/about-us/where-we-work/daresbury-laboratory/computational-chemistry/. Training on molecular dynamics methods and the use of DL_POLY (molecular dynamics package for condensed states), other related software, software development and the use of high performance computers will be provided at the Daresbury Laboratory (less than 20 miles from Liverpool).