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J/A+A/492/257     Collisional excitation of water in warm media   (Faure+, 2008)

Collisional excitation of water in warm astrophysical media. I. Rate coefficients for rovibrationally excited states Faure A., Josselin E. <Astron. Astrophys. 492, 257 (2008)> =2008A&A...492..257F
ADC_Keywords: Atomic physics Keywords: molecular data ; molecular processes ; ISM: molecules Abstract: The interpretation of water line emission from infrared and submillimetre observations requires a detailed knowledge of collisional rate coefficients over a wide range of levels and temperatures. We attempt to determine rotational and rovibrational rate coefficients for H2O colliding with both H2 and electrons in warm, molecular gas. Pure rotational rates are derived by extrapolating published data using a new method partly based on the information (phase space) theory of Levine and co-workers. Ro-vibrational rates are obtained using vibrational relaxation data available in the literature and by assuming a complete decoupling of rotation and vibration. Results. Rate coefficients were obtained for the lowest 824 ro-vibrational levels of H2O in the temperature range 200-5000K. Our data is expected to be accurate to within a factor of ∼5 for the highest rates (>10-11cm3/s). Smaller rates, including the ro-vibrational ones, should be generally accurate to within an order of magnitude. As a first application of this data, we show that vibrationally excited water emission observed in evolved stars is expected to be at least partly excited by means of collisions. Description: *Downward* pure rotational and ro-vibrational rates are provided for the 5 lowest vibrational levels of H2O and 11 temperatures (from 200 to 5000K). This corresponds to all possible transitions among the lowest 824th levels of H2O below 5000cm-1. Upward rates can be computed using the detailed balance relation (see article). Rate files are denoted as coll-ph2o-h2.dat and coll-oh2o-h2.dat for para-H20 and ortho-H20 colliding with H2, respectively, and coll-ph2o-e.dat and coll-oh2o-e.dat for para-H20 and ortho-H20 colliding with electrons, respectively. The labelling of para- and ortho-H2O levels in the rate files correspond to the labelling in files ortho-H2O.levels and para-H2O.levels. For vibrational levels the normal mode notation (v1v2v3) is employed (v1 corresponds to symmetric stretch, v2 to bending and v3 to antisymmetric stretch). File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file list.dat 100 6 List of files levels/* 37 2 *Energy levels of ortho-H2O and para-H2O rates/* 116 4 *De-excitation rates of para-H2O and ortho-H2O in collision with H2
Note on levels/*: Each level file contains the 11-lines header: # ! Energy levels of para-H2O # ! Ref: # ! Tennyson et al. J. Phys. Chem. Ref. Data, 30, 735-831 (2001) # ! Energy unit : # ! cm^-1 # ! Number of columns : # 6 # ! Number of Lines : # 413 # ! Level Energy J Ka Kc vib. Note on rates/*: Each rate file contains the 5-lines header: # ! NUMBER OF COLLISION TEMPERATURES # 11 # ! COLLISION TEMPERATURES # 200.0 400.0 800.0 1200.0 1600.0 2000.0 2500.0 3000.0 3500.0 4000.0 5000.0 # ! TRANS + UP + LOW + RATE COEFFS(cm^3 s^-1)
See also: VI/119 : High accuracy computed water line list - BT2 (Barber+, 2006) J/A+A/472/1029 : (De)excitation rates of H2O by H2 (Faure+, 2007) J/A+A/493/687 : Rotational excitation of formaldehyde by H2 (Faure+, 2009) J/MNRAS/399/425 : (De)excitation rates of ortho-NH3 and para-NH3 (Faure+, 2009) Byte-by-byte Description of file: list.dat
Bytes Format Units Label Explanations
1- 26 A26 --- FileName File name 28-100 A73 --- Title Title of the file
Byte-by-byte Description of file (# headlines): levels/*
Bytes Format Units Label Explanations
2- 4 I03 --- ilev Level number 7- 17 F11.6 cm-1 elev Energy value 21- 22 I2 --- J J quantum number 26- 27 I2 --- Ka Ka quantum number 31- 32 I2 --- Kc Kc quantum number 35- 37 I03 --- v1v2v3 v1v2v3 quantum numbers (G1)
Byte-by-byte Description of file (# headlines): rates/*
Bytes Format Units Label Explanations
1- 5 I5 --- itrans Transition number 9- 11 I03 --- i [2/413] Initial level 15- 17 I03 --- f [1/412] Final level 19- 26 E8.2 cm3/s k200 Rate coefficient at 200K 28- 35 E8.2 cm3/s k400 Rate coefficient at 400K 37- 44 E8.2 cm3/s k800 Rate coefficient at 800K 46- 53 E8.2 cm3/s k1200 Rate coefficient at 1200K 55- 62 E8.2 cm3/s k1600 Rate coefficient at 1600K 64- 71 E8.2 cm3/s k2000 Rate coefficient at 2000K 73- 80 E8.2 cm3/s k2500 Rate coefficient at 2500K 82- 89 E8.2 cm3/s k3000 Rate coefficient at 3000K 91- 98 E8.2 cm3/s k3500 Rate coefficient at 3500K 100-107 E8.2 cm3/s k4000 Rate coefficient at 4000K 109-116 E8.2 cm3/s k5000 Rate coefficient at 5000K
Acknowledgements: Alexandre Faure <afaure(at)obs.ujf-grenoble.fr> Global notes: Note (G1): The vibrational level is written as a 3-digit number v1v2v3, e.g. 010 or 120. It represents vibrational quanta in normal modes v1 (symmetric stretch), v2 (bending) and v3 (antisymmetric stretch), respectively.
History: * 28-Nov-2008: Original files * 27-Aug-2009: Some files removed (from author): levels: o-h2o.001.levels and p-h2o.001.levels) rates: o-h2o-h2-001-*, h2o-h2-001-*, o-h2o-e-001-*, p-h2o-e-001-*) * 25-Feb-2010: All original files removed, and replaced by NEW FILES
(End) Alexandre Faure [LAOG, France], Patricia Vannier [CDS] 18-Feb-2010
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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