The weak infrared spectrum of CO2-Ar corresponding to the (0111) <-- (0110) hot band of CO2 is detected in the region of the carbon dioxide ν3 fundamental vibration (~2340 cm-1),...

The infrared spectrum of CO 2 -Kr complex is studied in the region of the carbon dioxide ν 3 fundamental vibration ( � 2350 cm À 1 ). Tunable IR radiation from an OPO is employed to record absorption spectrum of the complex generated in a pulsed supersonic slit jet. The spectrum exhibits broadening and splitting of transitions due to mass dependence of the five Kr isotopes with natural abundances exceeding 2 %. Good simulation of the spectrum is achieved by scaling the vibrational and rotational parameters. This scaling model is partic-ularly important for the combination band involving the intermolecular bending mode where many isotope splittings are observed. As with other CO 2 -rare gas complexes, we also observe weak hot bands of CO 2 -Kr transitions corresponding to the hot band originating in the CO 2 intramolecular bend. From these we determine a splitting of 1.418 cm À 1 between the inplane and out-of-plane bend of CO 2 , due to the neighboring Kr atom.

The weak infrared spectrum of CO 2-Ar corresponding to the (v 1 , v l2 2 , v 3) = (01 1 1) ← (01 1 0) hot band of CO 2 is detected in the region of the carbon dioxide ν 3 fundamental vibration (∼2340 cm −1), using a tunable OPO to probe a pulsed supersonic slit jet expansion. While this method was previously thought to cool clusters to the lowest rotational states of the ground vibrational state, here we show that under suitable jet expansion conditions, sufficient population remains in the first excited bending mode of CO 2 (1-2%) to enable observation of vibrationally hot CO 2-Ar, and thus to investigate the symmetry breaking of the intramolecular bending mode of CO 2 in the presence of Ar. The bending mode of CO 2 monomer splits into an in-plane and an out-of-plane mode, strongly linked by a Coriolis interaction. Analysis of the spectrum yields a direct measurement of the in-plane / out-of-plane splitting measured to be 0.8770 cm −1. This aspect of intramolecular interactions has received little previous experimental and theoretical consideration. Therefore, we provide an additional avenue by which to study the intramolecular dynamics of this simplest dimer in its bending modes. Similar results are obtained for CO 2-Ne.

Spectra of water�CO 2 dimers are studied using a tunable midinfrared source to probe a pulsed slit jet supersonic expansion. H 2 O−CO 2 and D 2 O−CO 2 are observed in the CO 2 ν 3 fundamental region (≈2350 cm −1 ), D 2 O−CO 2 is also observed in the D 2 O ν 3 fundamental region (≈2790 cm −1 ), and HDO−CO 2 is observed in the HDO O−D stretch fundamental region (≈2720 cm −1 ), all for the first time in these regions. Analysis of the spectra yields excited state rotational parameters and vibrational shifts. They also yield the first experimental values of the ground state internal rotation tunneling splittings for D 2 O−CO 2 (0.003 cm −1 ) and HDO−CO 2 (0.0234 cm −1 ). The latter value is a direct determination made possible by the reduced symmetry of HDO−CO 2 . These results provide stringent and easily interpreted tests for theoretical water− CO 2 potential energy surface calculations.

The mid-infrared (MIR) contains the strong absorption signatures of many molecules that are of extreme interest in real-world sensing applications. The miniaturization of spectroscopic sensing equipment made possible by silicon photonics has the potential to revolutionize emission sensing in the MIR.Nanophotonic devices have greatly benefited from telecommunication technology in the near infrared (NIR) region. The industry has reached a level of maturity where high volume production of integrated circuitry can be done at low cost. Silicon based photonic devices can now support optical signals in the MIR past 8 microns with losses approaching those of the telecommunications band [1] making the region attractive for sensing applications.Absorption sensing with photonic devices has been demonstrated in silicon on sapphire, silicon nitride [2], and other silicon-on-insulator platforms. These methodologies have demonstrated the ability to sense analyte concentrations as low as 5000 ppmv (parts per million by volume), which is the workplace limit in many constituencies [3].We present our current state of research on the development of a high-quality factor MIR silicon-on-sapphire (SOS) photonic gas sensor for use in lab-on-a-chip sensing applications. An optical parametric oscillator (OPO) will be used as a MIR source to pump a grating coupled SOS ring cavity immersed in a controlled CO2 environment. The cavity will be geometrically engineered to allow for high sensitivity spectroscopy of trace CO2 near 2350cm-1. Design was conducted in COMSOL Multiphysics and Lumerical software suites. The sensor was patterned at Applied Nanotools in Edmonton, AB and is currently undergoing characterization in the laboratory at the University of Calgary.[1] R.