$${{{v}}_{2}}$$ -Dependences of the Rotational Contributions to the Effective Dipole Moment of the H₂O Molecule and Their Effect on the Broadening and Shift of Lines Induced by the Pressure of Buffer Gases

Abstract: The dependences of the rotational contributions to the effective dipole moment of the H₂O molecule on vibrational quantum number $${{{v}}_{2}}$$, which corresponds to the large-amplitude bending vibration of the molecule, have been determined numerically. Different representations for the dipole moment surface of the H₂O molecule and different potential functions that determine the set of vibrational states E($${{{v}}_{2}}$$) have been used in calculations. The effect of the calculated contributions on the broadening and shift of H₂O lines induced by the pressure of argon, krypton, hydrogen, and helium has been analyzed. It has been shown that this effect is significant for the shift of rotational lines and for the shift of lines from the vibrational bands for which the difference between the values of rotational quantum number K_a from the upper and lower states of the transition is greater than or equal to 3.