Molecular Growth in the Interstellar Medium

The presence and formation of a large variety of organic molecules in the interstellar medium (ISM) are evident from both astronomical data of absorption and emission bands at different regions of the spectrum. 
However, it is not clear how molecules are formed in the low temperature and density environments of the ISM.  
Specifically, polycyclic aromatic hydrocarbons (PAHs) are ubiquitous in the ISM. Understanding the mechanism of formation of complex molecules such as PAHs and nitrogen-based PAHs (PANH) in the ISM is a long-standing challenge that has been attracting growing attention in recent decades. 
We study a variety of possibilities for chemical reaction starting upon ionization of van der Waal clusters. 
The potential for different chemical reactions to occur within a cluster environment arises from the fact that such processes can take place at low temperatures as the systems contain large amounts of energy upon ionization. 
Moreover, the spectator molecules in the cluster can provide a dissipation route for energy by detachment from the cluster; thus the system can stabilize efficiently even at low densities

Representation of PES via Neural Networks
 

The dynamic evolution of molecular systems can be calculated using Ab-Initio Molecular dynamics. 
Such calculation can give very accurate results; however, preforming ab-initio calculation in every time-step of the molecular dynamics can be time-consuming. 
We are using Machine Learning (ML) algorithms, specifically artificial neural networks to construct potential energy surfaces. 
After the potential energy constructed, they will enable us to preforms simulations on a longer time scale and larger systems.