Line mixing in the water vapour transitions of the ν 1  + ν 2  + ν 3 band perturbed by helium pressure.

The line mixing effect for two pairs of transitions with rotational quantum numbers (3 1 2) ← (4 1 3), (3 2 1) ← (4 2 2), (4 3 1) ← (3 3 0) and (4 2 2) ← (3 2 1) in the ν1 + ν2 + ν3 band of H2O has been studied. The measurements were performed at room temperature, at the spectral resolution of 0.01 cm−1 and in a wide pressure range of helium. Pressure-broadening and -shifting coefficients and mixing parameter were obtained with help of the line profile using the Rosenkranz first-order approximation. [ABSTRACT FROM PUBLISHER]