In the present paper, the spectra of vibrational excited states for molecules (HO^3^5Cl, HO^3^7Cl, DO^3^5Cl and DO^3^7Cl) have been calculated using self consistant field configuration interaction (SCF-CI) approach. In these molecules (HO^3^7Cl, DO^3^5Cl and DO^3^7), the frequency shifts relative to HOCl species have been calculated out. These theoretical values is in agreement with observed values. From these calculated values on the vibrational excited states of molecules HO^3^5Cl, HO^3^7Cl, DO^3^5Cl and DO^3^7Cl, some unobserved vibrational excited states and their isotopic effects have been predicted based on the new potential energy surface of HOCl molecule.

Key words: EXCITED STATE, ISOTOPE EFFECT, SELF-CONSISTENT FIELD, HYDROGEN ISOTOPES, CONFIGURATION, CHLORINE ISOTOPES, HYPOCHLORIC ACID, POTENTIAL ENERGY SURFACES