Knowledge Bank

Water vapor lineshifts induced by nitrogen pressure have been measured at NIST (USA) and LPMA (France) using Fourier-spectrometers with a multi-pass absorption cells of 32 and 84 meters at 0.0025 and $0.01cm-1$ resolution in 1850 - 2230 $cm-1$ and 4900 - 5600 $cm-1$ spectral region. The special procedure have been used minimize errors connected with the assymetry of the contours due to apparatus effects in high pressure FTS-spectra. The fitting of Voigt contour parameters was used to obtain lineshift parameters. Accuracy of lineshift coefficient determination was better than 1 mk/atm. The lineshift coefficients have been determined for well resolved isolated lines belonging to 010-000 and 011-000 bands with high quantum numbers J up to 18. The lineshift coefficients have been calculated using the Anderson method and cut-of-free procedure. The dipole-quadrupole, quadrupole-quadrupole, dipole-hexadecapole and polarizational interactions were included in the calculations. The contributions of different type of intermolecular potentials and their dependences on J value will be discussed.