Intensity calculations of HCN molecules

Accurate spectroscopic data of HCN are required for many astronomical calculations and modeling. HCN molecules are present in the atmosphere of carbon stars and in galactic centers. Ro-vibrational energy levels and intensity calculations were carried out using the full coupled cluster model and radau coordinates. Accurate ab initio calculated potential energy surface$^{1}$ and dipole moment surface$^{2}$ were used for computation. The computed values were compared with Hitran$^{99}$.$^{ }$