Weeding the Astrophysical Garden Using Complete Experimental Spectra James P. McMillan, Christopher F. Neese, Satyakumar Nagarajan and Frank C. De Lucia Half a Decade of ALMA: Cosmic Dawns Transformed September 20, 2016 Indian Wells, CA

The problem of the ‘Weeds’ 6 Weeds found in the Hot Core of Orion KL Each Weed: Dense lab spectra, 100s – 1000s of lines Difficult to predict, 100s – 1000s of unpredicted spectral lines. Many unpredicted lines are of non-trival intensity Fortman et al. J.Mol.Spectrosc 280:11 (2012)

The problem of the ‘Weeds’ CH3CH2CN CH3CN CH2CHCN Goldsmith, P., Bergin, T., De Lucia, F. C., et al. 2006, Report from the Workshop on Laboratory Spectroscopy in Support of Herschel, SOFIA, and ALMA (Pasadena, CA: California Institute of Technology) Lines from perturbed excited vibrational states are difficult to predict CH3OH HCOOCH3 CH3CHO CH3OCH3

The problem of the ‘Weeds’ Incomplete Methyl Formate Predictions Each Weed: Dense lab spectra, 100s – 1000s of lines Difficult to predict, 100s – 1000s of unpredicted spectral lines. Many unpredicted lines are of non-trival intensity McMillan et al. ApJ 823:1 (2016)

Acquiring the Intensity Calibrated Complete Experimental Spectrum (CES) 10 Heaters Sample Transmitter THz Source Detector 6 meters Butterfly Valve Steps: 0 𝑡ℎ : Contamination 1 𝑠𝑡 : Pressure vs. Doppler Broadening 2 𝑛𝑑 : Acquire CES 0.02-0.2 K per scan; 1578 scans Local Thermodynamic Equilibrium

The Point-by-point Technique Doppler Broadened Naperian Absorbance: A(ν) =(1− 𝑒 − ℎ𝜈 𝑘𝑇 )( 𝑛𝐿 𝑄 )𝑆 𝑒 − 𝐸 𝑙 𝑘𝑇 𝐾 𝑇 𝑒 −ln 2 ( ν− 𝜈 0 𝛿𝜈 ) 2 A(ν) =(1− 𝑒 − ℎ𝜈 𝑘𝑇 )( 𝑛𝐿 𝑄 ) 𝑆 𝑒 − 𝐸 𝑙 𝑘𝑇 𝐾 𝑇 Doppler width: More constants: 𝛿ν= ν 𝑜 2 𝑁 𝑎 𝑘 𝑙𝑛(2) 𝑀 𝑐 2 𝑇 = W ν 𝑜 𝑇 K = 𝑊( 8 𝜋 3 3𝑐ℎ ln 2 𝜋 ) 𝐸 𝑙 = 𝐸 𝑙 +𝑘 ln 2 𝑊 2 (1− ν ν 𝑜 ) 2

The Point-by-point Technique Doppler Broadened Naperian Absorbance: A(ν) =(1− 𝑒 − ℎ𝜈 𝑘𝑇 )( 𝑛𝐿 𝑄 )𝑆 𝑒 − 𝐸 𝑙 𝑘𝑇 𝐾 𝑇 𝑒 −ln 2 ( ν− 𝜈 0 𝛿𝜈 ) 2 A(ν) =(1− 𝑒 − ℎ𝜈 𝑘𝑇 )( 𝑛𝐿 𝑄 ) 𝑆 𝑒 − 𝐸 𝑙 𝑘𝑇 𝐾 𝑇 Reduces to the familiar form Doppler width: More constants: 𝛿ν= ν 𝑜 2 𝑁 𝑎 𝑘 𝑙𝑛(2) 𝑀 𝑐 2 𝑇 = W ν 𝑜 𝑇 K = 𝑊( 8 𝜋 3 3𝑐ℎ ln 2 𝜋 ) 𝐸 𝑙 = 𝐸 𝑙 +𝑘 ln 2 𝑊 2 (1− ν ν 𝑜 ) 2

The Point-by-point Technique Input Output Calibrate T and nL/Q 𝐴 𝑝𝑒𝑎𝑘 =(1− 𝑒 − ℎν 𝑘𝑇 )(𝑆)( 𝑛𝐿 𝑄 ) 𝑒 − 𝐸 𝑙 𝑘𝑇 𝐾 𝑇 Fit a single scan; multiple lines Generate 𝐸 𝑙 and 𝑆 Fit a single frequency bin; all scans A(ν) =(1− 𝑒 − ℎ𝜈 𝑘𝑇 )( 𝑛𝐿 𝑄 ) 𝑆 𝑒 − 𝐸 𝑙 𝑘𝑇 𝐾 𝑇 Doppler width: More constants: 𝛿ν= ν 𝑜 2 𝑁 𝑎 𝑘 𝑙𝑛(2) 𝑀 𝑐 2 𝑇 = W ν 𝑜 𝑇 K = 𝑊( 8 𝜋 3 3𝑐ℎ ln 2 𝜋 ) 𝐸 𝑙 = 𝐸 𝑙 +𝑘 ln 2 𝑊 2 (1− ν ν 𝑜 ) 2

The Point-by-point Technique Predicts Complete Experimental Spectrum 1.) Simply Download the table of 𝑆 and 𝐸 𝑙 . 2.) Choose your temperature and plot! A(ν) =(1− 𝑒 − ℎ𝜈 𝑘𝑇 )( 𝑛𝐿 𝑄 ) 𝑆 𝑒 − 𝐸 𝑙 𝑘𝑇 𝐾 𝑇 McMillan et al. ApJ 823:1 (2016) Doppler width: More constants: 𝛿ν= ν 𝑜 2 𝑁 𝑎 𝑘 𝑙𝑛(2) 𝑀 𝑐 2 𝑇 = W ν 𝑜 𝑇 K = 𝑊( 8 𝜋 3 3𝑐ℎ ln 2 𝜋 ) 𝐸 𝑙 = 𝐸 𝑙 +𝑘 ln 2 𝑊 2 (1− ν ν 𝑜 ) 2

Astrophysical Analysis CH3CN In The Orion KL Hot Core Steps: 1.) Generate a complete experimental spectrum 2.) Convolve spectra with astrophysical line shape 3.) Adjust for column density Fortman et al. J.Mol.Spectrosc 280:11 (2012) 190K (LTE) Methyl Cyanide (CH3CN) ALMA

Astrophysical Analysis CH3CH2CN & CH2CHCN vs Orion Hot Core 190K - Ethyl Cyanide (CH3CH2CN) 190K - Vinyl Cyanide (CH2CHCN) ALMA CH313CN & Terrestrial vs Orion Hot Core 190K - 13C Methyl Cyanide 190K - Terrestrial Methyl Cyanide ALMA Fortman et al. J.Mol.Spectrosc 280:11-20 (2012)

Astrophysical Analysis Recover Temperature and Density Profiles Methyl Cyanide in the Orion Hot Core This new, velocity class based work, is featured on our poster! Still simulates to the accuracy of ALMA!

Laboratory Work Overview 210 – 270 Band Point-by-point Published ? Ethyl Cyanide Complete ApJ 725:1682--1687 (2010) Vinyl Cyanide ApJ 737:20 (2011) Methanol ApJ 795:56 (2014) Methyl Formate ApJ 823:1 (2016) Methyl Cyanide Draft in progress Dimethyl Ether In Progress No Acetaldehyde

Laboratory Work Overview 210 – 270 Band Point-by-point Published ? Ethyl Cyanide Complete ApJ 725:1682--1687 (2010) Vinyl Cyanide ApJ 737:20 (2011) Methanol ApJ 795:56 (2014) Methyl Formate ApJ 823:1 (2016) Methyl Cyanide Draft in progress Dimethyl Ether In Progress No Acetaldehyde

Laboratory Work Overview 210 – 270 Band Point-by-point Published ? Ethyl Cyanide Complete ApJ 725:1682--1687 (2010) Vinyl Cyanide ApJ 737:20 (2011) Methanol ApJ 795:56 (2014) Methyl Formate ApJ 823:1 (2016) Methyl Cyanide Draft in progress Dimethyl Ether In Progress No Acetaldehyde

Laboratory Work Overview 550 – 650 Band Point-by-point Published ? Ethyl Cyanide Complete ApJ 714:476-486 (2010) Methanol ApJ 782:2 (2014) Acetaldehyde Sample too old, to be redone No, but over 500 assignments made Methyl Cyanide Line shape issues, to be redone No, presented at the 2013 ISMS

Summary Simulation is spectrally complete Includes unanalyzed excited states Format available both as a line list catalog and in the point-by-point Shown that our results can be used for astronomy