Offset-locked CO2 waveguide laser study of formic acid: Reassessment of far-infrared laser assignments

A number of infrared transitions of formic acid were measured to a precision of better than 100 kHz. In the light of these new data, far-infrared laser measurements were reassessed. Available microwave data were also incorporated in deriving new parameters for the ν₆ and ν₈ states, including the $\text{ν}{}_6\text{ν}{}_8$a-type Coriolis interaction.