=============================================================================== ExoMol molecular line lists: The spectrum of nitric acid MRNAS 2015 A.I. Pavlyuchko, S.N Yurchenko and J. Tennyson Nitric acid is a possible biomarker in the atmospheres of exoplanets. An accurate line lists is computed for nitric acid (HNO3). This line list covers wavelenghts longer than 1.42 um (0-7000 cm-1) and temperatures up to 500 K. The line list is computed using a hybrid variational-perturbation theory and empirically tuned potential energy and dipole surfaces. It comprises almost 7 billion transitions involving rotations up to J = 100. Comparisons with spectra from the HITRAN and PNNL databases demonstrate the accuracy of our calculations. Synthetic spectra of water - nitric acid mixtures suggest that nitric acid has features at 7.5 and 11.25 um are capable of providing a clear signature for HNO3; the feature at 11.25 um is particularly promising. Partition functions plus full line lists of transitions are made available in an electronic form as supplementary data to the article and at www.exomol.com. Description: The data for each isotopologue are in two parts. The first, 1H-14N-16O3__AIJS.states contains a list of rovibronic states. Each state is labelled with the total angular momentum, state degeneracy, total parity, vibrational quantum number, projection of the electronic, spin and total angular momenta. Each state has a unique number, which is the number of the row in which it appears in the file. This number is the means by which the state is related to the second part of the data system, the transitions files. Because of their size, the transitions are listed in 71 separate files, each containing all the transitions in a 100 cm-1 wavenumber range. These and their contents are ordered by increasing frequency. The name of the file includes the lowest frequency in the range; thus the 1H-14N-16O3__AIJS__00500-00600.trans file contains all the transitions in the frequency range 500-600 cm-1. The transition files 1H-14N-16O3__AIJS*.trans contain three columns: the reference number in the energy file of the upper state; that of the lower state; and the Einstein A coefficient of the transition. File Summary: ------------------------------------------------------------------------------- FileName Explanations ------------------------------------------------------------------------------- README__AIJS.txt This file 1H-14N-16O3__AIJS*.trans Transition files 1H-14N-16O3__AIJS.states Labelled rovibronic states 1H-14N-16O3__AIJS.pf Partition function of HNO3 ------------------------------------------------------------------------------- Byte-by-byte description of files 1H-14N-16O3__AIJS*.trans ------------------------------------------------------------------------------- Bytes Format Units Label Explanations ------------------------------------------------------------------------------- 1- 12 i12 --- N' Upper state ID 14- 25 i12 --- N" Lower state ID 27- 36 e10.4 s-1 A Einstein A-coefficient of the transition ------------------------------------------------------------------------------- Byte-by-byte description of file 1H-14N-16O3__AIJS.states ------------------------------------------------------------------------------- Bytes Format Units Label Explanations ------------------------------------------------------------------------------- 1- 12 i12 --- N State ID, non-negative integer index 14- 25 i12 cm-1 E State energy term value in cm-1 27- 32 i6 --- g Total state degeneracy 34- 40 i7 --- J J-quantum number J$ is the total angular momentum excluding nuclear spin 45- 46 a1 --- A'/A" Total symmetry 53- 55 i2 --- n1 Normal mode vibrational quantum number 56- 58 i2 --- n2 Normal mode vibrational quantum number 59- 61 i2 --- n3 Normal mode vibrational quantum number 62- 64 i2 --- n4 Normal mode vibrational quantum number 65- 67 i2 --- n5 Normal mode vibrational quantum number 68- 70 i2 --- n6 Normal mode vibrational quantum number 71- 73 i2 --- n7 Normal mode vibrational quantum number 74- 76 i2 --- n8 Normal mode vibrational quantum number 77- 79 i2 --- n9 Normal mode vibrational quantum number ------------------------------------------------------------------------------- Contacts: S.N. Yurchenko, s.yurchenko@ucl.ac.uk J. Tennyson, j.tennyson@ucl.ac.uk ===============================================================================