The topic of this research is the hitherto uninvestigatedabsorption of electromagnetic energy by polar symmetric-topmolecules in a static electric field, which arises by virtue ofdirect transitions between sublevels of a single rotationalstate. A short theoretical treatment of the Stark effect of arigid molecule is included. The factors governing the absorptionof quanta from the surrounding radiation field are discussedin a rudimentary derivation of a formula for the maximum linearabsorption coefficient of a gas.
A new microwave Stark-effect spectrometer constructed foran exploratory investigation is described. The instrumentoperates in an unusual manner whereby the spectral position ofthe absorption line is varied, while the frequency of the incidentradiation is held fixed. Included also is a treatment of the factors which determine and limit the sensitivity of thespectrometer.
Experiments which strongly indicate the existence of thesefield-created absorption lines are reported.
