title: Density Functional Exploration of C4H3N Isomers.
abstract: Molecules having C4H3N stoichiometry are of astrophysical interest. Two of these, methylcyanoacetylene (CH3C3N) and its structural isomer allenyl cyanide (H2CCCHN), have been observed in interstellar space, while several more have been examined in laboratories. Here we describe, for a broad range of C4H3N isomers, density functional calculations (B3LYP/aug-cc-pVTZ) of molecular parameters including the energetics, geometries, rotational constants, electric dipole moments, polarizabilities, vibrational IR frequencies, IR absorption intensities, and Raman activities. Singlet-triplet splittings as well as singlet vertical electronic excitation energies are given for selected species. The identification of less stable C4H3N molecules, generated in ongoing spectroscopic experiments, relies heavily on these quantum chemical predictions.
authors.affiliation: Institute of Physical Chemistry, Polish Academy of Sciences , ul. Kasprzaka 44/52, 01-224 Warsaw, Poland.
authors.forename: Thomas
authors.initials: T
authors.lastname: Custer
authors.affiliation: Institute of Physical Chemistry, Polish Academy of Sciences , ul. Kasprzaka 44/52, 01-224 Warsaw, Poland.|Institut des Sciences Moléculaires d'Orsay (ISMO), CNRS, Université Paris-Sud, Université Paris-Saclay , F-91405 Orsay, France.
authors.forename: Urszula
authors.initials: U
authors.lastname: Szczepaniak
authors.affiliation: Institute of Physical Chemistry, Polish Academy of Sciences , ul. Kasprzaka 44/52, 01-224 Warsaw, Poland.
authors.forename: Marcin
authors.initials: M
authors.lastname: Gronowski
authors.affiliation: Institute of Physical Chemistry, Polish Academy of Sciences , ul. Kasprzaka 44/52, 01-224 Warsaw, Poland.
authors.forename: Emilia
authors.initials: E
authors.lastname: Fabisiewicz
authors.affiliation: Aix-Marseille Université , CNRS, PIIM, UMR 7345, 13013 Marseille, France.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Couturier-Tamburelli
authors.affiliation: Institute of Physical Chemistry, Polish Academy of Sciences , ul. Kasprzaka 44/52, 01-224 Warsaw, Poland.
authors.forename: Robert
authors.initials: R
authors.lastname: Kołos