First International Conference on MOLDAVIAN RISKS – FROM ...

<strong>First</strong> <strong>International</strong> <strong>Conference</strong> on MOLDAVIAN RISKS - FROM GLOBAL TO LOCAL SCALE
16-19 May 2012, Bacau, Romania
QUANTITATIVE DETERMINATIONS OF CARBON OXIDES
FROM ATMOSPHERE AFTER ELECTRONIC ABSORPTION
SPECTRA
Iuliana Caraman 1 , Oxana Racovet 2 , Dumitru Untila 2 , Silvia Evtodiev 2 ,
Marius Stamate 1
1 “Vasile Alecsandri” University of Bacau. Romania
2 Laboratory of Scientific Research "Photonics and Metrology Physics",
Moldova State University
Corresponding author: Iuliana Caraman, iucaraman@yahoo.ca
Abstract: In the process of carbonates burning and different chemical reactions with
organic compounds participating are forming diverse CO2 and CO carbon oxides. These
gases concentration relation determines in a meaningful measure the level of alimentary
products fermentation process. So, different technologic processes conducting are
necessary quantitative determinations of carbon oxides concentration (CO2, CO). In
present are elaborated chemical methods of measuring, but these need much time and
special equipment. This shortcoming it is not characteristic for optical methods after
absorption spectrums. As it was demonstrated through experimental measurements, CO2
and CO molecules don’t posed absorption electronic bands in visible domain and UV near
spectrum. The first electronic stare, absolute gap, of CO2 molecule (stare 2 Σ + g) is found at
45320cm -1 higher than fundamental stare 2 П3/2. Thus, fundamental absorption band of this
molecule is in the vacuum UV region (70000 ÷64000) cm -1 . In the paperwork it is analyzed
the intensity of the first overtone of the vibration bands v”=0 → v’=1 in dependence of the
CO2 and CO molecules concentration in atmosphere. These bands for CO2 and CO
molecules are situated respectively at ~ 4260 cm -1 and ~ 4700 cm -1 . Both absorption bands
on the 2168 cm - 1and 2347 cm -1 basis respective for CO2 and CO molecules and first
overtone represent bands with two branches P and R. for quantitative determinations of
these gases concentration in atmosphere was took the intensities ratio in the P branch
maximum of the R branch and the absorption intensity at 50 cm -1 from these maximums in
dependence of the gases concentration in atmosphere. Also, for verification there were
analyzed the P and R branches intensity ratio from the CO2 and CO molecules absorption
spectrums and the intensity at the maximum of vibration-rotation band of water vapors
from atmosphere. It was established the concentrations interval in which take place linear
dependence of the intensities ratio of CO2 and CO molecules concentration in normal
atmosphere. Investigations were made in the Laboratory of Scientific Research "Photonics
and Metrology Physics", Moldova State University.
Key words: carbon, concentration, absorption band, vibration-rotation.
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