The absorption spectrum of stable dimers in the long-wave wing of the rotation H2O band is estimated proceeding from available experimental data on the H2O continuum absorption in this region and calculations on the basis of the asymptotic line wing theory. The spectral line contour of the rotational band describing the spectral and temperature behavior of the H2O continuum absorption in the 8–12 μm range was used in the calculations. The spectrum derived does not conflict with computations with the dimer model of the continuum absorption.
water vapor, continuum absorption, spectral line wings, dimer absorption
1. Bauer A., Godon M., Carlier J., Ma Q., Tipping R.H. Absorption by H2O and H2O-N2 mixtures at 153 GHz // J. Quant. Spectrosc. Radiat. Transfer. 1993. V. 50, N 5. P. 463–475.
2. Kuhn T., Bauer A., Godon M., Buhler S., Kunzi K. Water vapor continuum: Absorption measurements at 350 GHz and model calculations // J. Quant. Spectrosc. Radiat. Transfer. 2002. V. 74. P. 545–562.
3. Furashov N.I., Katkov V.Yu. Humidity dependence of the atmospheric absorption coefficient in the transparency windows centered at 0.88 and 0.73 mm // Int. J. Infrared Mill. Waves. 1985. V. 6, N 8. P. 751–764.
4. Burch D.E., Gryvnak D.A. Method of calculating H2O transmission between 333 and 633 cm-1. Report AFGL-TR-79-0054. AFGL, 1979. 51 p.
5. Burch D.E. Continuum absorption by atmospheric H2O. Report AFGL-TR-81-0300. AFGL, 1982. 46 p.
6. Burch D.E. Continuum absorption by atmospheric H2O // Proc. SPIE. 1981. V. 277. P. 28–39.
7. Podobedov V.B., Plusquellic D.F., Siegrist K.E., Fraser G.T., Ma Q., Tipping R.H. New measurements of the water vapor continuum in the region from 0.3 to 2.7 THz // J. Quant. Spectrosc. Radiat. Transfer. 2008. V. 109. P. 458–467.
8. Odintsova T.A., Tretyakov M.Yu., Pirali O., Roy P. Water vapor continuum in the range of rotational spectrum of H2O molecule: New experimental data and their comparative analysis // J. Quant. Spectrosc. Radiat. Transfer. 2017. V. 187. P. 116–123.
9. Odintsova T., Tretyakov M.Yu., Zibarova A.O., Pirali O., Roy P., Campargue A. Far-infrared self-continuum absorption of H216O and H218O (15–500 cm−1) // J. Quant. Spectrosc. Radiat. Transfer. 2019. V. 227. P. 190–200.
10. Odintsova T.A., Tretyakov M.Y., Simonova A.A., Ptashnik I.V., Pirali O., Campargue A. Measurement and temperature dependence of the water vapor self-continuum between 70 and 700 cm-1 // J. Mol. Structure. 2020. V. 1210. P. 128046.
11. Odintsova T.A., Koroleva A.O., Simonova A.A., Campargue A., Tretyakov M.Yu. The atmospheric continuum in the “terahertz gap” region (15–700 cm-1): Review of experiments at SOLEIL synchrotron and modeling // J. Mol. Spectrosc. 2022. V. 386. P. 111603-1–111603-10.
12. Tret'yakov M.Yu., Koshelev M.A., Serov E.A., Parshin V.V., Odintsova T.A., Bubnov G.M. Dimer vody i atmosfernyj kontinuum // Uspekhi fiz. nauk. 2014. V. 184, N 11. P. 1199–1215.
13. Nesmelova L.I., Rodimova O.B., Tvorogov S.D. Kontur spektral'noj linii i mezhmolekulyarnoe vzaimodejstvie. Novosibirsk: Nauka, 1986. 216 p.
14. Bogdanova Yu.V., Rodimova O.B. Sootnoshenie mezhdu pogloshcheniem monomerami i dimerami vodyanogo para v predelah vrashchatel'noj polosy Н2О // Optika atmosf. i okeana. 2018. V. 31, N 5. P. 341–348; Bogdanova Yu.V., Rodimova O.B. Ratio between monomer and dimer absorption in water vapor within the H2O rotational band // Atmos. Ocean. Opt. 2018. V. 31, N 5. P. 457–465.
15. Clough S.A., Kneizys F.X., Davies R.W. Line shape and the water vapor continuum // Atmos. Res. 1989. V. 23, N 3–4. P. 229–241.
16. Bogdanova Yu.V., Rodimova O.B. Line shape in far wings and water vapor absorption in a broad temperature interval // J. Quant. Spectrosc. Radiat. Transfer. 2010. V. 111, N 15. P. 2298–2307.
17. Baranov Y.I., Lafferty W.J., Ma Q., Tipping R.H. Water-vapor continuum absorption in the 800–1250 cm−1 spectral region at temperatures from 311 to 363 K // J. Quant. Spectrosc. Radiat. Transfer. 2008. V. 109. P. 2291–2302.
18. Paynter D.J., Ptashnik I.V., Shine K.P., Smith K.M. Pure.water.vapour continuum measurements between 3100 and 4400 cm-1: Evidence for water dimer absorption in near atmospheric conditions // Geophys. Res. Lett. 2007. V. 34, N 12. P. L12808-1–5.
19. Viktorova A.A., Zhevakin S.A. Pogloshchenie mikroradiovoln dimerami vodyanogo para atmosfery // Dokl. AN SSSR. 1970. V. 194, N 3. P. 540–543.
20. Lee M.-S., Baletto F., Kanhere D.G., Scandolo S. Far-infrared absorption of water clusters by first-principles molecular dynamics // J. Chem. Phys. 2008. V. 128. P. 214506-1–5.
21. Scribano Y., Leforestier C. Contribution of water dimers absorption to the millimeter and far infrared atmospheric water continuum // J. Chem. Phys. 2007. V. 126. P. 234301-1–234301-12.
22. Ptashnik I.V., Shine K.P., Vigasin A.A. Water vapour self-continuum and water dimers: 1. Analysis of recent work // J. Quant. Spectrosc. Radiat. Transfer. 2011. V. 112. P. 1286–1303.
23. Podobedov V.B., Plusquellic D.F., Fraser G.T. Investigation of the water-vapor continuum in the THz region using a multipass cell // J. Quant. Spectrosc. Radiat. Transfer. 2005. V. 91. P. 287–295.