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CAVIAR science meeting 29th Sept 2010 (National Physical Laboratory)

Stephen BallLeicester University

• Submitted to Atmospheric Chemistry & Physics: 2nd August• Editor assigned: 24th August• Editor’s report: 26th August• Manuscript + minor revisions submitted: 13th Sept• Accepted for discussion: 19th Sept• Production files submitted: 27th Sept• Type setting manuscript / galley proof / publication as an online

discussion paper…

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Result 1: The UCL_08 line list does a better job of fitting the water monomer structure than HITRAN08

Result 2: No evidence of a dimer feature like Pfeilsticker’s in the BBCRDS residual.…. but there might be something if the dimer band is very wide

Result 3: Dimer band would have to be extremely wide (HWHM > 100 cm-1) for any signal lurking in the BBCRDS residual to be consistent with (i) Keq and (ii) theoretical line strengths

Keq

??

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Where is the Leicester work now?

Leicester CAVIAR post-doc’s contract ended 30th April 2010.

SMB back in the lab this summer? – some apparatus improvements, but no new experiments.

• Dual heater around pulsed nozzle; Slit design• 10,000 cavity passes• The baseline noise on BBCRDS spectra of water monomer at low pressures demonstrate detection system is operating as well as for the Shillings et al study.

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Is it worth continuing?

Shillings et al (exp) & Garden et al 2008 (theory) suggest that dimer bands around 750 nm will be very broad: • difficult to observe in experiments under equilibrium conditions • requires non-equilibrium cooled experiments: the many dimer transitions that merge to form a wide feature at room temp now cooled to a series of narrower resolvable bands?

The hardware is in good shape; the apparatus is still available.

MChem 4th year project student – recruited:• SMB back in the lab next semester!

Kuyanov-Prozument