  Ice is a major component of astrophysical environment - from interstellar
molecular clouds through protoplanetary disks to evolved solar systems. Ice and
complex organic matter coexist in these environments as well, and it is thought
primordial ice brought the molecules of life to Earth four billion years ago,
which could have kickstarted the origin of life on Earth. To understand the
journey of ice and organics from their origins to becoming a part of evolved
planetary systems, it is important to complement high spatial and spectral
resolution telescopes such as JWST with laboratory experimental studies that
provide deeper insight into the processes that occur in these astrophysical
environments. Our laboratory studies are aimed at providing this knowledge. In
this article we present simultaneous mass spectrometric and infrared
spectroscopic investigation on how molecular ice mixtures behave at different
temperatures and how this information is critical to interpret observational
data from protoplanetary disks as well as comets. We find that amorphous to
crystalline water ice transformation is the most critical phenomenon that
differentiates between outgassing of trapped volatiles such as CO2 vs.
outgassing of pure molecular ice domains of the same in a mixed molecular ice.
Crystalline water ice is found to trap only a small fraction of other volatiles
(<5%), indicating ice grain composition in astrophysical and planetary
environments must be different depending on whether the ice is in amorphous
phase or transformed into crystalline phase, even if the crystalline ice
undergoes radiation-induced amorphization subsequently. Crystallization of
water ice is a key differentiator for many ices in astronomical environments as
well as in our Solar System.
