Room temperature detection of the (H) dimer.

The hydrogen dimer, (H), is among the most weakly bound van der Waals complexes and a prototype species for first principles studies. The detection of the (H) infrared absorption spectrum was reported more than sixty years ago at a temperature of 20 K. Due to the sharp decrease of the (H) abundance with temperature, detection at room temperature was generally considered hardly achievable.

Assignment of the methanol OH-stretch overtone spectrum using the pattern recognition method.

We present the measurement and analysis of the 2OH stretching band of methanol between 7165 cm and 7230 cm cooled down to 26 ± 12 K in a buffer gas cooling experiment. Measurements were performed with a cavity ring-down spectrometer having a detection limit = 2 × 10 cm. A total of 350 rovibrational transitions were assigned and 62 rovibrational transitions were tentatively assigned.

First detection and absolute transition frequencies in the (3-0) band of D2.

Three electric quadrupole transitions in the second overtone band of D2 are newly measured by comb-referenced cavity ring down spectroscopy around 1.18 µm. These extremely weak transitions (line intensities smaller than 10-29 cm/molecule) are the first to be detected in the (3-0) band of D2.

Frequency stable and low phase noise THz synthesis for precision spectroscopy.

We present a robust approach to generate a continuously tunable, low phase noise, Hz linewidth and mHz/s stability THz emission in the 0.1 THz to 1.4 THz range.

Accurate absolute frequency measurement of the S(2) transition in the fundamental band of H near 2.03 μm.

A series of spectra of the quadrupolar electric S(2) transition of H in the 1-0 band near 4917 cm has been recorded at seven pressure values between 2 and 100 Torr. The comb-referenced cavity ring down spectroscopy (CR-CRDS) technique was used for the recording of this very weak transition. The accuracy of the spectrum frequency axis is achieved by linking the CRDS setup to an optical frequency comb referenced to a GPS-referenced 10 MHz rubidium clock.