Hot NH3 Spectra for Astrophysical Applications

Abstract

We present line lists for ammonia (NH${}_3$) at high temperatures obtained by recording Fourier transform infrared emission spectra. Calibrated line lists are presented for twelve temperatures (300 -- 1300${}^{\circ }$C in 100${}^{\circ }$C intervals and 1370${}^{\circ }$C) and each line list covers the 740 -- 2100 cm${}^{-1}$ range, which includes the majority of the ${\nu }_2$ umbrella bending mode region (11 $\mu$m) and the ${\nu }_4$ asymmetric bending mode region (6.2 $\mu$m). We also demonstrate the useful technique of obtaining empirical lower state energies from a set of spectra recorded at different sample temperatures. Using our NH${}_3$ spectra, we have estimated lower state energies ($E_{Low}$ in cm${}^{-1}$) and our values have been incorporated into the line lists along with calibrated wavenumbers ($\tilde{\nu }$ in cm${}^{-1}$) and calibrated line intensities ($S^{\prime }$ in cm/molecule) for each line. We expect our hot NH${}_3$ line lists to find direct application in the modelling of planetary atmospheres and brown dwarfs.

References in corpus (4)

• Atomic and Molecular Opacities for Brown Dwarf and Giant Planet Atmospheres
• Low-Mass Dwarf Template Spectra from the Sloan Digital Sky Survey
• CFBDS J005910.90-011401.3: reaching the T-Y Brown Dwarf transition?
• Physical and Spectral Characteristics of the T8 and Later-Type Dwarfs

Cited by in corpus (8)

• ExoMol molecular line lists XXXV: a rotation-vibration line list for hot ammonia
• New H2 collision-induced absorption and NH3 opacity and the spectra of the coolest brown dwarfs
• Temperature-dependent molecular absorption cross sections for exoplanets and other atmospheres
• Empirical line lists and absorption cross sections for methane at high temperature
• Laboratory spectra of hot molecules: data needs for hot super-Earth exoplanets
• The Dawes Review 3: The Atmospheres of Extrasolar Planets and Brown Dwarfs
• A near infrared line list for \NH: Analysis of a Kitt Peak spectrum after 35 years
• High-resolution absorption measurements of NH3 at high temperatures: 2100 - 5500