1 research outputs found
Biomolecule Analogues 2‑Hydroxypyridine and 2‑Pyridone Base Pairing on Ice Nanoparticles
Ice nanoparticles (H<sub>2</sub>O)<sub><i>N</i></sub>, <i>N</i> ≈ 450 generated
in a molecular beam experiment pick up individual gas phase molecules
of 2-hydroxypyridine and 2-pyridone (HP) evaporated in a pickup cell
at temperatures between 298 and 343 K. The mass spectra of the doped
nanoparticles show evidence for generation of clusters of adsorbed
molecules (HP)<sub><i>n</i></sub> up to <i>n</i> = 8. The clusters are ionized either by 70 eV electrons or by two
photons at 315 nm (3.94 eV). The two ionization methods yield different
spectra, and their comparison provides an insight into the neutral
cluster composition, ionization and intracluster ion–molecule
reactions, and cluster fragmentation. Quite a few molecules were reported <i>not to coagulate</i> on ice nanoparticles previously. The (HP)<sub><i>n</i></sub> cluster generation on ice nanoparticles
represents the first evidence for coagulating of molecules and cluster
formation on free ice nanoparticles. For comparison, we investigate
the coagulation of HP molecules picked up on large clusters Ar<sub><i>N</i></sub>, <i>N</i> ≈ 205, and also (HP)<sub><i>n</i></sub> clusters
generated in supersonic expansions with Ar buffer gas. This comparison
points to a propensity for the (HP)<sub>2</sub> dimer generation on
ice nanoparticles. This shows the feasibility of base pairing for
model of biological molecules on free ice nanoparticles. This result
is important for hypotheses of the biomolecule synthesis on ice grains
in the space. We support our findings by theoretical calculations
that show, among others, the HP dimer structures on water clusters