PREDNASAJUCI / LECTURER : 

Zuzana Kaňuchová

NAZOV / TITLE : 

Processing of ices in space by energetic particles: synthesis and radiolysis of organics


ABSTRAKT / ABSTRACT : 

Ices are widely present in the cold regions across the Universe. 
They are present in the interstellar medium as mantles on interstellar 
and circumstellar dust and on the surfaces of small bodies of the 
Solar System – beyond the distance around 3-5 AU known as the “snowline” 
(i.e. below 150-170 K). It is commonly thought that energetic processing of interstellar 
and planetary ices plays a relevant role in astrochemistry and astrobiology. 
Ionizing radiation (UV photons, electrons, ions from cosmic rays or solar wind) 
induces several physico-chemical processes such as radiolysis and subsequent formation of new molecules, 
as, for example complex organic molecules (COMs). Once formed in space, COMs are themselves 
exposed to the complex radiation field, and the question how long can they survive arises. 
It is useful to investigate their radiation resistance in order to determine the survival 
times of complex molecules. We have studied the radiolysis of the complex organic molecule pyridine. 
Pure pyridine (C5H5N) and mixed pyridine-water ices (T = 12 K) were irradiated with swift ions at two 
beam lines (SME: 650 MeV Zn26+, ARIBE: 90 keV O6+) of the GANIL facility (Caen, France). 
The evolution of the IR absorption lines of pyridine in the ices was measured as a function of projectile 
fluence with a FTIR spectrometer in CIMAP's CASIMIR device at CIMAP, GANIL. 
From the exponential decrease of the peak intensities, destruction cross sections of pyridine 
were calculated in pure and mixed ices. Also, the appearance of radiolytic products were followed by in-situ 
infrared absorption.