IR SPECTROSCOPY WITH A DOUBLE MODULATION SIDEBAND TECHNIQUE

Author Institution: Abteilung Physikalische Chemie, Universit\""{a}t Ulm, Einsteinallee; Laboratoire de Spectronomie, Mol\'{e}culaire et InstrumentationWe have applied both microwave and radio frequency modulation to $CO_{2}$ laser lines using only one CdTe modulator. As a result, a grid of closely spaced ($\Delta\nu\times 1 MHz$) and tunable infrared frequencies is generated. This technique was used to perform infrared-infrared double resonance experiments on the molecules $^{28}SiH_{4}$ and $^{28}SiF_{4}$ and to observe the Stark splitting due to extremely small dipole moments. As a preliminary result we obtained values for several dipole moment parameters which agree with measurements performed with other techniques