Radiolysis of pyridine in solid water

Abstract

We irradiated the complex organic molecule pyridine and mixtures of pyridine and water in solid phase (thin icy films) at 12K at different beam lines of the GANIL facility (ARIBE: 90 keV O 6+ , SME: 650 MeV Zn 26+ ). The destruction of the initial molecule and the appearance of radiolytic products were followed by in-situ infrared absorption spectroscopy as a function of the projectile fluence with the CASIMIR experimental set-up of CIMAP. We measured the destruction cross section as a function of pyridine concentration. A clear dependence on the percentage of pyridine in H2O was found: the destruction cross sections are significantly higher for small concentration, i.e. pure pyridine is more radioresistant than pyridine diluted in water ice at 12 K. Thus, the presence of water environment significantly modifies the radiation resistance of the initial complex organic molecules: it enhances radiosensitivity and destruction of pyridine, with implications for radiobiology and astrochemistry.

Neutral Dissociation of Pyridine Evoked by Irradiation of Ionized Atomic and Molecular Hydrogen Beams

“…Focused ion beams are employed for etching, deposition, and direct-write lithography and fabrication technology [ 13 , 14 ] and for sample imaging in ion microscopes [ 15 , 16 , 17 ]. However, the most intense studies are performed to elucidate the ion-induced alterations to structure blocks of living cells, mainly the DNA/RNA molecules [ 18 , 19 , 20 , 21 , 22 ] and their analogs [ 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 ]. The reason is that the ionic beams are effectively applied in hadrontherapy to irradiate the cancerous cells [ 33 , 34 , 35 ].…”

“…The interaction of ions with biological molecules in the gas phase leads to ionization, excitation, charge transfer, complex formation, and dissociation processes that produce neutral and ionic products [ 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 ]. The mass spectrometric methods are developed to probe the charged entities [ 22 , 39 ], as well as to study neutral fragments in high-Rydberg states but without identifying their final states [ 40 , 41 ].…”