Laser induced fluorescence spectra of expansion-cooled NOz/Ne samples (1 and 2 K) are reported for transitions that originate from the lowest rovibronic levels and terminate on levels near Do. At I K, nearly all transitions originate from N"=O. With the present resolution of 0.02 cm -1, the I K spectra are resolved rather well. The high density of transitions is due to couplings between rovibronic levels with different Nand K quantum numbers and with electronic characters that borrow oscillator strength from bright B 2 vibronic species of the mixed 2 A 1;2 B 2 electronic system. Just above reaction threshold, such rovibronic species comprise the manifold of levels sampled by optically prepared wave packets. However, at higher energies we argue that the density of B z vibronic species is a more relevant parameter to describe the nature of unimolecular reactions. Nuances of the optical excitation process are discussed.
The rovibrational absorption spectrum of the weakly bound cluster CO 2 -N 2 O has been observed in the region of the ν 3 CO 2 asymmetric stretch (∼2350 cm -1 ). Clusters were formed by supersonic expansion of a mixture of N 2 O:CO 2 in a 4:1 ratio using He carrier gas. Approximately 340 lines have been assigned. Both parallel and perpendicular transitions were observed. The ground state rotational constants A, B, and C are 0.294 924-(12), 0.058 004(6), and 0.048 400(6) cm -1 , respectively. The quartic centrifugal distortion constants are D j ) 5.03(17) × 10 -7 cm -1 , D jk ) -3.92(9) × 10 -6 cm -1 , D k ) 1.26(2) × 10 -5 cm -1 , δ j ) 1.61(92) × 10 -8 cm -1 , and δ k ) 1.77(80) × 10 -6 cm -1 . Ab initio calculations for several CO 2 -N 2 O equilibrium structures have been done on the Hartree-Fock self-consistent field level using a 6-311g* basis set. Møller-Plesset MP2 and MP3 calculations were carried out for the two possible slipped parallel configurations of the dimer. The planar slipped parallel geometry with the oxygen atom of N 2 O nearest the CO 2 monomer was found to be the most stable structure. The spectral constants and stabilization energies were compared to those of the CO 2 and N 2 O homodimers. A planar slipped parallel geometry is observed with the O of N 2 O nearly over the C of CO 2 . R cm and θ are 3.4701 Å and 60.1°, respectively, assuming the CO 2 and N 2 O are parallel to each other.
The Mars Science Laboratory (MSL), comprising a cruise stage; an aeroshell; an entry, descent, and landing system; and the radioisotope thermoelectric generator-powered Curiosity rover, made history with its unprecedented sky crane landing on Mars on August 6, 2012. The mission's primary science objective has been to explore the area surrounding Gale Crater and assess its habitability for past life. Because microbial contamination could profoundly impact the integrity of the mission and compliance with international treaty was required, planetary protection measures were implemented on MSL hardware to verify that bioburden levels complied with NASA regulations. By applying the proper antimicrobial countermeasures throughout all phases of assembly, the total bacterial endospore burden of MSL at the time of launch was kept to 2.78×10⁵ spores, well within the required specification of less than 5.0×10⁵ spores. The total spore burden of the exposed surfaces of the landed MSL hardware was 5.64×10⁴, well below the allowed limit of 3.0×10⁵ spores. At the time of launch, the MSL spacecraft was burdened with an average of 22 spores/m², which included both planned landed and planned impacted hardware. Here, we report the results of a campaign to implement and verify planetary protection measures on the MSL flight system.
The available data on the microwave spectrum of the hydroxyl radical are critically reviewed for information applicable to radio astronomy. Molecular properties such as the rotational constants, spinorbit, spin-spin and hyperfine coupling cons lams and cemrifugal distonion parameters employed in or derived from the analysis are tabulated. All the observed and predicted transitions of 060H, ~,OD, and DOH below 300 GHz and lower state energy levels less than 4000 cm-I are presented for the ground vibrational state. The laboratory data on IlOH is included, but no predicted transitions are presented due to thc limited data available. In addition to the transition frequencies the table contains the calculated line strengths and energies of the levels involved in the transition. An extensive bibliography of laboratory and astronomical studies of the hydroxyl'radical is presented as an aid to workers in both fields.,
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