The clustering of rovibrational energy levels in the highly excited H~2O molecule has been investigated by using a variational procedure and the bending-rotation Hamiltion in which the radial cooridates are fixed to their equilibrium values. This clustring effects begins with thecritical value of total angular momentum J~c, which for H~2O is 26. The appearance of four-fold clusters of energy levels as consequence of molecular geometry stabilization is predicted. This clustering structure has not been brokendown in the excited vibrational states.

Key words: FUNCTION, QUANTUM MECHANICS, VARIATIONAL METHOD, TRIATOMIC MOLECULE, CRITICAL STATE