15min:

N. INOSTROZA, Departamento de Astrofísica Molecular e Infrarroja, Instituto de Estructura de la Materia, C.S.I.C., Serrano 121, Madrid 28006, SPAIN; M. L. SENENT, Departamento de Astrofísica Molecular e Infrarroja, Instituto de Estructura de la Materia, C.S.I.C., Serrano 121, Madrid 28006, SPAIN.

Structural and spectroscopic properties of the astrophysically relevant SiC₃H^- anion are investigated at the RCCSD(T) and CASSCF levels of theory. The molecule presents a total of 12 isomers (4 lineal and 8 cyclic), all of them showing singlet ground electronic states. The stability of the linear isomer l-SiC₃H^- (X^{1 -} ) is notorious. The B0 rotational constant of l-Si¹²C₃H^- and l-Si¹²C₃D^- , the dipole moment, excitation energies to the lowest electronic states and electron affinities have been estimated.