In:
Review of Scientific Instruments, AIP Publishing, Vol. 87, No. 6 ( 2016-06-01)
Kurzfassung:
Concentration-modulated noise-immune cavity-enhanced optical heterodyne molecular spectroscopy (NICE-OHMS) is implemented for the first time on a continuous gas-flow pinhole supersonic expansion discharge source for the study of cooled molecular ions. The instrument utilizes a continuous-wave optical parametric oscillator easily tunable from 2.5 to 3.9 μm and demonstrates a noise equivalent absorption of ∼1 × 10−9 cm−1. The effectiveness of concentration-modulated NICE-OHMS is tested through the acquisition of transitions in the ν1 fundamental band of HN2+ centered near 3234 cm−1, with a signal-to-noise of ∼40 obtained for the strongest transitions. The technique is used to characterize the cooling abilities of the supersonic expansion discharge source itself, and a Boltzmann analysis determines a rotational temperature of ∼29 K for low rotational states of HN2+. Further improvements are discussed that will enable concentration-modulated NICE-OHMS to reach its full potential for the detection of molecular ions formed in supersonic expansion discharges.
Materialart:
Online-Ressource
ISSN:
0034-6748
,
1089-7623
Sprache:
Englisch
Verlag:
AIP Publishing
Publikationsdatum:
2016
ZDB Id:
209865-9
ZDB Id:
1472905-2
SSG:
11