Nitrogen Substituted Polycyclic Aromatic Hydrocarbon As Capable
  Interstellar Infrared Spectrum Source Considering Astronomical Chemical
  Evolution Step To Biological Organic Purine And Adenine
  In order to find out capable chemical evolution step from astronomically
created organic in interstellar space to biological organic on the earth,
infrared spectrum of nitrogen substituted carbon pentagon-hexagon coupled
polycyclic aromatic hydrocarbon was analyzed by the density functional theory.
Ionization was modeled from neutral to tri-cation. Among one nitrogen and two
nitrogen substituted NPAH, we could find good examples showing similar IR
behavior with astronomically well observed one as like C8H6N1, C7H5N2, and
C7H5N2. We can imagine that such ionized NPAH may be created in interstellar
space by attacks of high energy nitrogen and photon. Whereas, in case of three
and four nitrogen substituted cases as like C6H4N3 and C5H3N4, there were no
candidate showing similar behavior with observed one. Also, IR of typical
biological organic with four and five nitrogen substituted one as like purine
and adenine resulted no good similarity with observed one. By such theoretical
comparison, one capable story of chemical evolution of PAH in interstellar
space was that one and two nitrogen substituted carbon pentagon-hexagon
molecules may have a potential to be created in interstellar space, whereas
more than three nitrogen substituted molecules including biological organic
purine and adenine may not be synthesized in space, possibly on the earth.
