Home – Home – Jornals – Atmospheric and Oceanic Optics 2014 number 5

Wall-collision broadening and shift of the water vapor absorption lines was measured within 5000-5600 cm^–1 with the IFS 125 HR Fourier spectrometer. It has been shown, that tight confinement of the molecules by the nanopores of silica aerogel leads to the strong lines broadening and shift. The half-widths at half maximum of spectral lines of the water vapor under nano-environment are on the average 23 times larger than those for the free molecules at a pressure of 10 mbar. A model that simulates the absorption profile of H₂O molecule, confined in nanopores, is presented. It assumes that half-width Γ of the absorption H₂O molecule is a sum of two parts, Γ_Wall and Γ_if. The first part, Γ_Wall, is connected with the wall collisions and it gives the main contribution to the half-width for all absorption lines. The best correlation between experimental and calculated half-widths is obtained when the second rotationally depended part, Γ_if, is connected with the collisions between (H₂O) molecules having (in comparison with free H₂O molecules) modified electro-optical parameters due to influence of pore’s surface. The data on the half-widths and center shifts for some strongest H₂O lines have been presented. The agreement between calculated and experimental half-width is satisfactory.