CHARACTERIZATION OF $C_3HSi^-$

Author Institution: Departamento de Astrofisica Molecular e Infrarroja; Instituto de Estructura de la Materia, C.S.I.C., Serrano 121; Madrid 28006, SPAIN; Departamento de Astrofisica Molecular e Infrarroja; Instituto de Estructura de la Materia, C.S.I.C., Serrano 121; Madrid 28006, SPAINStructural and spectroscopic properties of the astrophysically relevant $SiC_3H^-$ 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}-SiC_3H^- (X^1 \Sigma^- ) $ is notorious. The B0 rotational constant of ${l}-Si^{12}C_3H^- $ and ${l}-Si^{12}C_3D^- $, the dipole moment, excitation energies to the lowest electronic states and electron affinities have been estimated