# From clouds to protoplanetary disks: the astrochemical link

4-8 October 2015
Hans Harnack Haus
Europe/Berlin timezone
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# Contribution Contributed Talk

Hans Harnack Haus -
FROM PROTOSTARS TO PROTOPLANETARY DISKS 2

# The role of fundamental surface processes on astrochemistry: a computational chemistry perspective

## Speakers

• Dr. Herma CUPPEN

## Content

The formation of many saturated species that have been observed in a wide variety of astronomical objects cannot be explained by gas phase chemistry alone and it is clear that surface chemistry must play a crucial role. Most of this chemistry occurs through a diffusive mechanism. Gas-grain models which include this type of chemistry, use however many assumptions on input parameters such as diffusion rates and on the structure of the ice mantle.

I will show how computational chemistry tools can help to get more information on fundamental surface processes such as diffusion and energy dissipation. This information can serve as input for astrochemical models. I will show how these processes impact not only on the surface chemistry but also on thermal and non-thermal desorption rate, such as reactive desorption. Non-thermal desorption is often envoked to explain observed gas phase abundances in cold regions. I will focus on simple molecular species, like CO, H$_2$O, CH$_4$, and CO$_2$, but I aim to make it more general to obtain predictive power for more complex species.