Electric Dipole Moments of Acetone and of Acetic Acid Measured in Supersonic Expansion

Precise values for electric dipole moments of isolated acetone and acetic acid molecules were determined from the Stark effect measurements made on lowest J rotational transitions at conditions of supersonic expansion. The new results are μtot = μb = 2.9345(22) D for acetone from measurements on the 111 ← 101 transition, and μa = 0.8631(8), μb = 1.4345(11), μtot = 1.6741(10) D for acetic acid, from measurements on 111 ← 000 and 101 ← 000 transitions. A comparison with previous determinations and with results of quantum chemical calculations is presented.