VI/119 High accuracy computed water line list - BT2 (Barber+, 2006) =============================================================================== A high accuracy computed water line list - BT2. Barber R.J., Tennyson J., Harris G.J., Tolchenov R.N. =2006MNRAS.368.1087B =============================================================================== ADC_Keywords: Atomic physics Keywords: water - line list - BT2 - molecular spectra Abstract: A computed list of H2O infra-red transition frequencies and intensities is presented. The list, BT2 was produced using a discrete variable representation two-step approach for solving the rotation-vibration nuclear motions. It is the most complete water line list in existence, comprising over 500 million transitions (65% more than any other list) and is also the most accurate (over 90% of all experimental levels are within 0.3cm^-1^ of the BT2 values). Its accuracy has been confirmed by extensive testing against astronomical and laboratory data. The line list has been used to identify water lines in a variety of objects including: comets, sunspots, a brown dwarf and the nova-like object V838 Mon. Comparison of the observed intensities with those generated by BT2 enables physical values to be derived for these objects. The line list can also be used to provide an opacity for models of the atmospheres of M-dwarf stars and assign previously unknown water lines in laboratory spectra. Description: The data are in two parts. The first, the 'Levels File' (levels.dat) is a list of 221,097 energy levels, ordered by J and symmetry block. About 25,000 of these energy levels have been labelled with the appropriate angular momentum (J,Ka,Kc) and vibrational (v1,v2,v3) quantum numbers. The second part of BT2 is the 'Transitions File'. This has 505,806,202 entries. Each transition references upper and lower energy levels in the Levels File and gives the Einstein Aif coefficient for the transition. In uncompressed form the BT2 Transitions File is 12.6Gb of data. Therefore, in order to facilitate use of the list, the transitions have been ordered by frequency and separated into 16 smaller files, each representing a specific frequency range. These have labels of the form: 1H2-16O__BT2__02750-03500-BT2.trans where the two five digit numbers represent the lower and upper ends of the frequency range for that particular file. These files are zipped and need to be unzipped using the command 'bunzip2 filename'. File Summary: ------------------------------------------------------------------------------- Filename Lrecl Records Description ------------------------------------------------------------------------------- README.txt 79 - This file 1H2-16O__BT2__00000-00250-BT2.trans 48 17490214 00000-00250 cm-1 1H2-16O__BT2__00250-00500-BT2.trans 48 17022667 00250-00500 cm-1 1H2-16O__BT2__00500-00750-BT2.trans 48 16530697 00500-00750 cm-1 1H2-16O__BT2__00750-01000-BT2.trans 48 16098481 00750-01000 cm-1 1H2-16O__BT2__01000-01500-BT2.trans 48 30866787 01000-01500 cm-1 1H2-16O__BT2__01500-02000-BT2.trans 48 29161189 01500-02000 cm-1 1H2-16O__BT2__02000-02250-BT2.trans 48 13954798 02000-02250 cm-1 1H2-16O__BT2__02250-02750-BT2.trans 48 26727622 02250-02750 cm-1 1H2-16O__BT2__02750-03500-BT2.trans 48 37249656 02750-03500 cm-1 1H2-16O__BT2__03500-04500-BT2.trans 48 44635822 03500-04500 cm-1 1H2-16O__BT2__04500-05500-BT2.trans 48 39325124 04500-05500 cm-1 1H2-16O__BT2__05500-07000-BT2.trans 48 50083781 05500-07000 cm-1 1H2-16O__BT2__07000-09000-BT2.trans 48 52289428 07000-09000 cm-1 1H2-16O__BT2__09000-14000-BT2.trans 48 76679377 09000-14000 cm-1 1H2-16O__BT2__14000-20000-BT2.trans 48 31640191 14000-20000 cm-1 1H2-16O__BT2__20000-30000-BT2.trans 48 6050421 20000-30000 cm-1 1H2-16O__BT2.states 76 221097 The 221,097 energy levels (some with ro-vibrational assignments). ------------------------------------------------------------------------------- Byte-by-byte Description of transitions files: *-BT2.trans ------------------------------------------------------------------------------- Bytes Format Units Label Explanations ------------------------------------------------------------------------------- 1 - 12 I12 --- Level1 Reference level in Energy Level File 14 - 26 I12 --- Level2 Reference level in Energy Level File 28 - 38 E10.4 s-1 A Einstein A coefficient ------------------------------------------------------------------------------- Byte-by-byte Description of energy levels file: 1H2-16O__BT2.states ------------------------------------------------------------------------------- Bytes Format Units Label Explanations ------------------------------------------------------------------------------- 1 - 12 I12 --- Level [1,221097] Number of the level 14 - 25 F12.6 cm-1 E [0.,30000.] Energy of the level 27 - 32 I6 --- g_tot Total statistical degeneracy of the level 34 - 40 I7 --- J [0,50] Total angular momentum quantum number 42 A1 --- parity [+,-] 44 - 45 I2 --- Gamma [1,4] Symmetry block number (1) 47 - 56 I10 --- N Reference within the symmetry block 58 A1 --- nucspin [o,p] Nuclear spin isomer label(2) 60 - 61 A2 --- Gamma_rve [A1, A2, B1, B2] Rovibrational symmetry label 63 - 64 I2 --- v1 [0,8] v1 symmetric stretch quantum number(3) 66 - 67 I2 --- v2 [0,17] v2 bend quantum number 69 - 70 I2 --- v3 [0,7] v3 asymmetrics stretch quantum number 72 - 73 I2 --- Ka [0,47] Ka rotational quantum number 75 - 76 I2 --- Kc [0,50] Kc rotational quantum number ------------------------------------------------------------------------------- Note (1): Symmetry block numbered as in Table 1 of paper: --------------------------------------------------------- J parity (even/odd) e e e e o o o o vibrational basis symmetry (q) e e o o e e o o rotational parity (p) e o e o e o e o ortho/para state (O/P) P O O P O P P O Symmetry Block number (code) 1 3 4 2 3 1 2 4 ---------------------------------------------------------- Note (2): o => ortho-H2O, p => para-H2O Note (3): unassigned quantum numbers are indicated with '*' ------------------------------------------------------------------------------- Contacts: R.J. Barber, bob(at)theory.phys.ucl.ac.uk J. Tennyson, j.tennyson(at)ucl.ac.uk G. J. Harris, greg(at)theory.phys.uc.ac.uk =============================================================================== (End) Bob Barber [Univ. Coll. London] 13-Jan-2006 updated to ExoMol format C. Hill (UCL) 11/6/2013