Observations of deuterated species have long proven essential to probing the properties and thermal history of the interstellar medium. With new observations from Herschel and ALMA we will be able to probe new environments and reveal multitudes of new molecules, including multi-deuterated species. To prepare for these observations we present an elaborate chemical network that includes tens of thousands of reactions with multi-deuterated species, both gas-phase and surface, in which the most recent information on deuterium chemistry is implemented.
Our model successfully explains observed D/H ratios of many single, double, and triple-deuterated molecules simultaneously, including water, methanol, ammonia, and hydrocarbons under a variety of space conditions. We indicate species that are particularly sensitive to temperature gradients and initial chemical composition, and perform an in-depth study of the evolution of selected essential species such as water and methanol. We list the most abundant observable deuterated species predicted by our model in different environments of low- and high-mass star-formation regions.