Feasibility of V/STOL concepts for short-haul transport aircraft

Feasibility of V/STOL concepts for short-haul transport aircraf

Rotational spectrum of cis–cis HOONO

The pure rotational spectrum of cis-cis peroxynitrous acid, HOONO, has been observed. Over 220 transitions, sampling states up to J(')=67 and K-a(')=31, have been fitted with an rms uncertainty of 48.4 kHz. The experimentally determined rotational constants agree well with ab initio values for the cis-cis conformer, a five-membered ring formed by intramolecular hydrogen bonding. The small, positive inertial defect Delta=0.075667(60) amu A(2) and lack of any observable torsional splittings in the spectrum indicate that cis-cis HOONO exists in a well-defined planar structure at room temperature

Rotational spectroscopy and dipole moment of cis-cis HOONO and DOONO

The rotational spectrum of cis-cis HOONO has been studied over a broad range of frequencies, 13–840 GHz, using pulsed beam Fourier-transform microwave spectroscopy and room-temperature flow cell submillimeter spectroscopy. The rotational spectrum of the deuterated isotopomer, cis-cis DOONO, has been studied over a subset of this range, 84–640 GHz. Improved spectroscopic constants have been determined for HOONO, and the DOONO spectrum is analyzed for the first time. Weak-field Stark effect measurements in the region of 84–110 GHz have been employed to determine the molecular dipole moments of cis-cis HOONO [µa=0.542(8) D,µb=0.918(15) D,µ=1.07(2) D] and DOONO [µa=0.517(9) D,µb=0.930(15) D,µ=1.06(2) D]. The quadrupole coupling tensor in the principal inertial axis system for the 14N nucleus has been determined to be chiaa=1.4907(25) MHz,chibb=–4.5990(59) MHz,chiab=3.17(147) MHz, and chicc=3.1082(59) MHz. Coordinates of the H atom in the center-of-mass frame have been determined with use of the Kraitchman equations, |aH|=0.516 Å and |bH|=1.171 Å. The inertial defects of HOONO and DOONO are consistent with a planar equilibrium structure with significant out-of-plane H atom torsional motion. Comparisons of the present results are made to ab initio calculations

Near-UV photolysis cross sections of CH_3OOH and HOCH_2OOH determined via action spectroscopy

Knowledge of molecular photolysis cross sections is important for determining atmospheric lifetimes and fates of many species. A method and laser apparatus for measurement of these cross sections in the near-ultraviolet (UV) region is described. The technique is based on action spectroscopy, where the yield of a photodissociation product (in this case OH) is measured as a function of excitation energy. For compounds yielding OH, this method can be used to measure near-UV photodissociation cross section as low as 10−23 cm2 molecule−1. The method is applied to determine the photodissociation cross sections for methyl hydroperoxide (CH3OOH; MHP) and hydroxymethyl hydroperoxide (HOCH2OOH; HMHP) in the 305–365 nm wavelength range. The measured cross sections are in good agreement with previous measurements of absorption cross sections

Evaluation of Experimental Zoysiagrasses in Southern Kansas

Kansas State University has been cooperating with Texas A&M AgriLife Research – Dallas to identify zoysiagrasses that are superior in quality to ‘Meyer,’ the industry standard, and that have equivalent or better freeze tolerance. Six of eight experimental crosses between select Zoysia cultivars were established in Wichita, Kansas, in 2009 and since that time have had consistently superior ratings in three or more measures

Near-IR photodissociation of peroxy acetyl nitrate

Measurements of the C-H overtone transition strengths combined with estimates of the photodissociation cross sections for these transitions suggest that near-IR photodissociation of peroxy acetyl nitrate (PAN) is less significant (Jnear−IR ~3×10^−8 s^−1 at noon) in the lower atmosphere than competing sinks resulting from unimolecular decomposition and ultraviolet photolysis. This is in contrast to the photochemical behavior of a related peroxy nitrate, pernitric acid (PNA), that undergoes rapid near-IR photolysis in the atmosphere with Jnear−IR ~10^−5 s^−1 at noon (Roehl et al., 2002). This difference is attributed to the larger binding energy and larger number of vibrational degrees of 10 freedom in PAN, which make 4[Greek nu]CH the lowest overtone excitation with a high photodissociation yield (as opposed to 2[Greek nu]OH in PNA)