Computational Study and Laboratory Spectroscopy of Prebiotic Molecules Produced by O( 1 D) Insertion Reactions Brian Hays, Bridget Alligood DePrince, and Susanna Widicus Weaver Emory University

Prebiotic Astrochemistry Photolysis Reactions H 2 O + h OH + H H 2 + O CH 3 OH + h CH 3 + OH CH 3 O + H CH 2 OH + H NH 3 + h NH 2 + H Radical-Radical Recombination Reactions CH 2 OH + OH CH 2 (OH) 2 CH 3 O + CH 2 OH CH 3 OCH 2 OH CH 2 OH + NH 2 NH 2 CH 2 OH H2OH2O CO H 2 CO CH 3 OH NH 3 HO CO HCO CH 3 O NH 2 CH 3 CH 2 OH H H HO h NH 2 CH 2 OH CH 2 (OH) 2 CH 3 OCH 2 OH Garrod, Widicus Weaver, & Herbst, Ap. J. 682 (2008)

Prebiotic Astrochemistry Photolysis Reactions H 2 O + h OH + H H 2 + O CH 3 OH + h CH 3 + OH CH 3 O + H CH 2 OH + H NH 3 + h NH 2 + H Radical-Radical Recombination Reactions CH 2 OH + OH CH 2 (OH) 2 CH 3 O + CH 2 OH CH 3 OCH 2 OH CH 2 OH + NH 2 NH 2 CH 2 OH H2OH2O CO H 2 CO CH 3 OH NH 3 HO CO HCO CH 3 O NH 2 CH 3 CH 2 OH H H HO h NH 2 CH 2 OH CH 2 (OH) 2 CH 3 OCH 2 OH Garrod et. al. Ap. J. 682 (2008)

Prebiotic Astrochemistry Ices evaporate, releasing molecules into the interstellar medium Photo Credit:T.A. Rector and T. Abbott, U. Alaska and NOAO, AURA, NASA. NGC 3582

Prebiotic Astrochemistry Ices evaporate, releasing molecules into the interstellar medium Molecules can undergo ion-neutral reactions in the gas phase Charnley, S. B. 1997, in IAU Colloq. 161, (Bologna: Editrice Compositori), 89

Proposed Formation Route for Laboratory Spectroscopy Molecules unstable under terrestrial conditions; no laboratory spectrum available Produce these molecules using efficient O( 1 D) insertion reactions

O( 1 D) Insertion Reactions Barrierless reactions of excited oxygen atoms and closed shell molecules Insert into X-H bonds – X= H, C, N Chang and Lin, Chem. Phys. Lett. 363 (2002) eV energy E O( 1 D) O( 3 P) Products undergo unimolecular dissociation unless excess vibrational energy is quenched

O( 1 D) Insertion Reactions Does O( 1 D) preferentially insert into N-H or C-H bonds? aminomethanol

O( 1 D) Insertion Reactions Does O( 1 D) preferentially insert into N-H or C-H bonds? n-methyl hydroxylamine forms from O( 1 D) insertion into N-H bond aminomethanol n-methylhydroxylamine

Calculations GAUSSIAN 09 i using the Emory University Cherry L. Logan Emerson Center for Scientific Computing Molecules included: methanediol, methoxymethanol, aminomethanol, n-methylhydroxylamine Geometry optimization, torsional barrier energies, dipole moments, conformer energies, and rotational constants using MP2/AUG-cc-pVTZ level of theory Spectra predicted with CALPGM ii program suite i. Firsch et. al., Gaussian 09 Revision ii. Pickett, J. Mol. Spectrosc. 1991, 148, 371–377

Methanediol ConstantMethanediol A (GHz) B (GHz) C (GHz) μ X (Debye) μ Y (Debye) μ Z (Debye) Hydroxyl wag ~ 1689 cm -1 O( 1 D) + methanol methanediol

Methoxymethanol ConstantMethoxymethanol A (GHz) B (GHz) C (GHz) μ X (Debye) μ Y (Debye) μ Z (Debye) Hydroxyl wag ~ 1697 cm -1 Methyl rotor ~ 669 cm -1 O( 1 D) + dimethylether methoxymethanol

Aminomethanol and n-methylhydroxylamine n-methylhydroxylamine aminomethanol O( 1 D) + methylamine

Aminomethanol ConstantAminomethanol A (GHz) B (GHz) C (GHz) μ X (Debye) μ Y (Debye) μ Z (Debye)1.341 Amine wag ~2140 cm -1 Hydroxyl wag ~684 cm -1

N-methylhydroxylamine ConstantCalculationsExperimental i A (GHz) B (GHz) C (GHz) μ X (Debye) μ Y (Debye) μ Z (Debye)-0.130(-0.012) 1/2 ~0 V 3 barrier predicted = 1384 cm -1 experimentall = 1243 cm -1 i. Sung and Harmony, J. Mol. Spec. 74, (1979) Methyl rotor ~1384 cm -1 Hydroxyl wag ~2405 cm -1

Experiment Direct absorption spectroscopy using Perry multipass coupled to submm source Detection within a supersonic expansion using double modulation lock-in amplification scheme

Experiment Direct absorption spectroscopy using Perry multipass coupled to submm source Detection within a supersonic expansion using double modulation lock-in amplification scheme See Carroll et al. FC04

Possible O( 1 D) Insertion Sources 185 nm CH 3 OH + Ar O( 1 D) Interaction region N2ON2O 253 nm Interaction region O 3 + CH 3 OH + Ar Larger initial number density Low absorption coefficient Methanol also absorbs at 185 nm, necessitating fast mixing Small spot to focus UV lamp Small initial number density Large absorption coefficient Methanol does not absorb at 253 nm, no fast mixing necessary Focus UV at throat of the expansion

Ozone Spectra

Future Work Search for O 2 ( 1 Δ ) as an indicator of O( 1 D) production Optimize insertion mechanism to produce known molecule: CH 4 + O( 1 D) → CH 3 OH Search for target molecules in lab Search for molecules in interstellar medium

Acknowledgments The Widicus Weaver group: Jake Laas, Jay Kroll, & Thomas Anderson Dr. Michael Heaven for helpful discussions Dr. Brooks Pate for loan of equipment Cherry L. Logan Emerson Center for Scientific Computing NASA APRA Grant NNX11AI07G NASA Herschel OT1 Analysis Program RSA No