Multi-nozzle molecular beam apparatus and experiments/theory of vapor-phase mixing in amorphous solid water

Herein are contained a design of a multi-nozzle vapor deposition molecular beam apparatus for ultra-high vacuum applications, experimental results and conclusions regarding surface templating of crystallization in amorphous solid water and its effect on self-mixing via vapor phase transport, and equations derived to describe vapor-phase transport in porous media. It was found that implementation of the multi-nozzle vapor deposition apparatus delivered repeatable and pure exposures of vapor even after months of use. Based on temperature-programmed desorption experiments in ultra-high vacuum, crystallization of amorphous solid water films were templated from the film-vacuum interface by depositing water at 142 K. This templating accelerated self-mixing, supporting the notion that self-mixing does not occur by a bulk diffusion mechanism; rather, a porous network created upon crystallization facilitates vapor-phase transport.