Isotope effects in dipole-bound anions of acetone

Precision measurements using the Rydberg charge-exchange and electric field-detachment methods find that the dipole-bound electron affinity (EA) of acetone (C₃H₆O) is 55 ± 10 μeV greater than for deuterated acetone (C₃D₆O). The result agrees well with a theoretical prediction obtained with high-level electronic-structure and anharmonic vibrational calculations. The dipole moments calculated for the vibrationally averaged structures of C₃H₆O and C ₃D₆O show that the isotope effect (2% reduction) on the EA of acetone is mainly due to a slight reduction (0.5%) of the average dipole moment upon deuteration.