MOLECULAR UNIVERSE

1. Water in the Universe
Water is a cornerstone molecule in interstellar chemistry – influencing the abundances of many other species – and it can be a dominant reservoir of elemental oxygen in the gas phase. Because of its many levels, water is also an important coolant, which can dominate the energy balance of the gas in such regions. This occurs in a very subtle way through a delicate balance between absorption of IR continuum radiation and rotational line emission; often in the same transition. The many water levels with their different Einstein A values also provide a powerful diagnostic of the physical conditions in the emitting gas.

2. Carbon chemistry
Complex carbonaceous molecules are omnipresent in space. For these large carbonaceous molecules, identification of specific molecules in space will have to be made through observations of their electronic transitions in the visible and ultraviolet or through their low ro-vibrational transitions in the submillimeter. Both of these types of transitions are unique tools for the identification of the specific molecules present in space.

3. Deuterium chemistry
Deuterium fractionation provides a powerful diagnostic tool for astronomy as the observed deuterium enhancement reflects the chemical routes involved, the actual energetic differences of the molecular species involved, and the local physical conditions. A concerted research effort will be directed towards identifying the chemical routes, the spectroscopy of deuterated species and their excitation.