Adsorbate Partition Functions via Phase Space Integration: Quantifying the Effect of Translational Anharmonicity on Thermodynamic Properties

• DOI: 10.1021/acs.jpcc.1c04009
• Publication Date: 2021-09-09T17:00:49Z
• Authors: Katrín Blöndal; Khachik Sargsyan; David H. Bross; Branko Ruscic; C. Franklin Golds...
• Keywords: Thermodynamic integration; Maxima and minima

A new method for computing anharmonic thermophysical properties adsorbates on metal surfaces is presented. Classical Monte Carlo phase space integration performed to calculate the partition function motion of a hydrogen atom Cu(111). minima-preserving neural network potential energy surface used within routine. Two different sampling schema generating training data are presented, and two density functionals used. The results benchmarked against direct state counting by using discrete variable representation. in excellent quantitative agreement with benchmark results. Additionally, both representation confirm that H Cu(111) highly anharmonic. were applied free dissociative adsorption H2 resulting Langmuir isotherms at 400, 800, 1200 K partial pressure range 0–1 bar. It shows effects lead significantly higher predicted site fractions hydrogen.