# Hamiltonian of a water molecule bounded to a surface

Where can I find a way to construct the hamiltonian of a water molecule bounded to a surface? More generally,how can one write the hamiltonian of an atom bounded to a surface?

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There are lots of different models for water and its interactions, depending on what you want to do with them.

Here are some entry points:

They either contain an explicit Hamiltonian or refer to one.

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• Langmuir model: the simplest, most effective. The Hamiltonian is defined as: 0 if the atom is not on the surface, $-\epsilon$ if it is. Divide your surface as an ensemble of $N$ possible adsorption sites, and treat using statistical physics in the grand-canonical ensemble ($\mu, V, T$). Enjoy!