Study of overtones and combination bands in the infrared spectrum of ONCl

Abstract The 2ν 1 , 2ν 1 +ν 3 , 2ν 1 +ν 2 , 2ν 1 +2ν 2 , 3ν 1 , 3ν 1 +ν 3 and 4ν 1 infrared bands of ONCl have been recorded. A least-squares calculation over a few lines of the 3ν 1 band of 16 O 14 N 35 Cl, with arms deviation of 0.003 cm − , provided values for several constants of the ν 1 =3 level.