Microwave spectroscopy and molecular structure of isonitrosyl hydroxide

Microwave spectroscopy and molecular structure of isonitrosyl hydroxide (HOON) Kyle N. Crabtree, Oscar Martinez, Jr. , and Michael C. Mc. Carthy Harvard-Smithsonian Center for Astrophysics Marat R. Talipov Marquette University Sergey L. Khursan Ufa Scientific Centre Gerard D. O’Connor University of Sydney

HONO and atmospheric chemistry Nitrous acid (HONO) involved in heterogeneous atmospheric/soil nitrogen cycle H. Su et al. 2011, Science, 333, 1616 -1618 G. Maier et al. 2000, Chem. Eur. J. 6, 800 -808

HONO and atmospheric chemistry Nitrous acid (HONO) involved in heterogeneous atmospheric/soil nitrogen cycle Product of OH + NO rxn assumed to be HONO, but X + NO XNO and XON in ice matrices (X = Cl, F, etc). So what about HOON? H. Su et al. 2011, Science, 333, 1616 -1618 G. Maier et al. 2000, Chem. Eur. J. 6, 800 -808

HOON in the literature S. Nakamura et al. 1987, J. Am. Chem. Soc. 109, 4142 -4148 T. Fueno et al 1991, Theo. Chim. Acta 82, 299 -308

HOON in the literature S. Nakamura et al. 1987, J. Am. Chem. Soc. 109, 4142 -4148 T. Fueno et al 1991, Theo. Chim. Acta 82, 299 -308

Possible stability of HOON? HOON calculated to be stable (CCSD(T)/aug-ccp. VTZ); admixture of radical-pair, ion-pair, and covalently-bound nitrene character Trans isomer more stable than cis (DE 7 k. J/mol) M. R. Talipov et al. 2013, J. Phys. Chem. A, 117, 679 -685

HOON vs. HOOO Detected by FTM spectroscopy H 2 O + O 2 discharge O—O bond: 1. 68 Å D(O—O) = 12 k. J mol-1 HOON Not detected H 2 O + NO discharge? O—O bond: 1. 89 Å (calc) D(O—O) = 33 k. J mol-1 (calc) Suma et al. 2005, Science, 308, 1885 -1886; Talipov et al. 2013, J. Phys. Chem. A, 117, 679 -685; Mc. Carthy et al. 2012, J. Chem. Phys. 136, 034303; Le Picard et al. 2010, Science, 328, 1258 -1262

Techniques: FTM spectroscopy Fourier transform spectrometer (5 -43 GHz, 1 MHz bandwidth) Supersonic expansion discharge nozzle H 2 O(g) + NO diluted in Ne HV

Techniques: FTM spectroscopy Fourier transform spectrometer (5 -43 GHz, 1 MHz bandwidth) Supersonic expansion discharge nozzle H 2 O(g) + NO diluted in Ne pol pulse HV

Techniques: FTM spectroscopy Fourier transform spectrometer (5 -43 GHz, 1 MHz bandwidth) Supersonic expansion discharge nozzle H 2 O(g) + NO diluted in Ne HV

Techniques: FTM spectroscopy Fourier transform spectrometer (5 -43 GHz, 1 MHz bandwidth) Supersonic expansion discharge nozzle FT of FID spectrum Doppler splitting H 2 O(g) + NO diluted in Ne HV

Techniques: MW-MW double resonance f. FTM J = 2 f. FTM J = 1 J = 0

Techniques: MW-MW double resonance f. FTM f. DR f. FTM J = 2 J = 1 J = 0

Techniques: MW-MW double resonance f. FTM f. DR f. FTM J = 2 J = 1 J = 0

Techniques: MW-MW double resonance f. FTM f. DR f. FTM J = 2 J = 1 J = 0

Search for HOON Geometry & vibrational corrections: CCSD(T)/aug-cc-p. VTZ cis-HOON A 0: 89200 MHz B 0: 8220 MHz C 0: 7520 MHz ma: 2. 2 D mb: 1. 0 D trans-HOON A 0: 84170 MHz B 0: 8745 MHz C 0: 7909 MHz ma: 1. 5 D mb: 1. 7 D

Search for HOON Geometry & vibrational corrections: CCSD(T)/aug-cc-p. VTZ cis-HOON A 0: 89200 MHz B 0: 8220 MHz C 0: 7520 MHz ma: 2. 2 D mb: 1. 0 D trans-HOON A 0: 84170 MHz B 0: 8745 MHz C 0: 7909 MHz ma: 1. 5 D mb: 1. 7 D

Search for HOON Geometry & vibrational corrections: CCSD(T)/aug-cc-p. VTZ cis-HOON A 0: 89200 MHz B 0: 8220 MHz C 0: 7520 MHz ma: 2. 2 D mb: 1. 0 D trans-HOON A 0: 84170 MHz B 0: 8745 MHz C 0: 7909 MHz ma: 1. 5 D mb: 1. 7 D

Search for HOON Geometry & vibrational corrections: CCSD(T)/aug-cc-p. VTZ cis-HOON A 0: 89200 MHz B 0: 8220 MHz C 0: 7520 MHz ma: 2. 2 D mb: 1. 0 D cis: 15740 MHz trans: 16650 MHz trans-HOON A 0: 84170 MHz B 0: 8745 MHz C 0: 7909 MHz ma: 1. 5 D mb: 1. 7 D

Potential detection 14 N hyperfine splitting Theoretical values: cis: 15740 MHz trans: 16650 MHz

Potential detection 14 N hyperfine splitting Corresponding 202 -101 transition found at 32605 MHz. Linked by double resonance Theoretical values: cis: 15740 MHz trans: 16650 MHz

Additional evidence: isotopic shifts B-1 Ib = Smiri, b 2 (likewise for A & C) b c NO + H 2 O a

Additional evidence: isotopic shifts B-1 Ib = Smiri, b 2 (B+C)calc (likewise for A & C) (B+C)obs normal b c NO + H 2 O a (B+C)calc (B+C)pred isotopologue

Additional evidence: isotopic shifts B-1 Ib = Smiri, b 2 (B+C)calc (likewise for A & C) (B+C)obs normal b c NO + H 2 O (B+C)calc (B+C)pred isotopologue f(101 -000) iso = fnormal - Dfiso a

Additional evidence: isotopic shifts B-1 Smiri, b 2 Ib = (B+C)calc (likewise for A & C) (B+C)obs normal b 15 N c 15 NO a + H 2 O (B+C)calc (B+C)pred isotopologue f(101 -000) iso = fnormal - Dfiso Species Df cis (calc) Df trans (calc) Df (obs) HOO 15 N 405 399 393 Frequencies in MHz

Additional evidence: isotopic shifts B-1 Ib = Smiri, b 2 (B+C)calc (likewise for A & C) (B+C)obs normal b (B+C)calc (B+C)pred isotopologue f(101 -000) iso = fnormal - Dfiso c 18 O NO + H 218 O a Species Df cis (calc) Df trans (calc) Df (obs) HOO 15 N 405 399 393 HO 18 ON 133 141 139 Frequencies in MHz

Additional evidence: isotopic shifts B-1 Ib = Smiri, b 2 (B+C)calc (likewise for A & C) (B+C)obs normal b 18 O c NO + H 218 O (B+C)calc (B+C)pred isotopologue f(101 -000) iso = fnormal - Dfiso a Species Df cis (calc) Df trans (calc) Df (obs) HOO 15 N 405 399 393 HO 18 ON 133 141 139 H 18 OON 983 939 Frequencies in MHz

Additional evidence: isotopic shifts B-1 Ib = Smiri, b 2 (B+C)calc (likewise for A & C) (B+C)obs normal b c D NO + D 2 O (B+C)calc (B+C)pred isotopologue f(101 -000) iso = fnormal - Dfiso a Species Df cis (calc) Df trans (calc) Df (obs) HOO 15 N 405 399 393 HO 18 ON 133 141 139 H 18 OON 983 939 DOON 516 905 848 Frequencies in MHz

Detection of trans-HOON + isotopologues Species (# lines) HOON (38) DOON (17) HOO 15 N (13) H 18 OON (17) HO 18 ON (13) Spectroscopic constants derived for all species Abundance: 3% relative to HONO

Semi-experimental equilibrium structure determination (reexp) Combine observed ground-state rotational constants with ab initio zero-point corrections Inertial defect: D = C-1 − A-1 − B-1

Semi-experimental equilibrium structure determination (reexp) Combine observed ground-state rotational constants with ab initio zero-point corrections Inertial defect: D = C-1 − A-1 − B-1

Semi-experimental equilibrium structure determination (reexp) Combine observed ground-state rotational constants with ab initio zero-point corrections Inertial defect: D = C-1 − A-1 − B-1 Species D (amu Å2) HOO 15 N 0. 00167 HOON HO 18 ON H 18 OON DOON 0. 00163 0. 00233 0. 00146 0. 00405

Semi-experimental equilibrium structure determination (reexp) Combine observed ground-state rotational constants with ab initio zero-point corrections Inertial defect: D = C-1 − A-1 − B-1 r(O-O) r(O-H) OON r(O-N) HOO Species D (amu Å2) HOO 15 N 0. 00167 HOON HO 18 ON H 18 OON DOON 0. 00163 0. 00233 0. 00146 0. 00405

Structure of HOON Semi-experimental (reexp) CCSD(T)/aug-cc-PV 5 Z MRCC/aug-cc-p. VTZ High-precision structure: lengths to 0. 001 Å, angles to <0. 1 Surprisingly large differences between reexp and ab initio O—O bond length > 1. 91 Å K. N. Crabtree et al. 2013, Science, 342, 1354 -1357

O-O bond in HOON K. N. Crabtree et al. 2013, Science, 342, 1354 -1357

O-O bond in HOON K. N. Crabtree et al. 2013, Science, 342, 1354 -1357

Summary and prospects K. N. Crabtree et al. 2013, Science, 342, 1354 -1357

Summary and prospects cis-HOON? K. N. Crabtree et al. 2013, Science, 342, 1354 -1357

Summary and prospects 17 O cis-HOON? 17 O K. N. Crabtree et al. 2013, Science, 342, 1354 -1357

Summary and prospects Cl 17 O cis-HOON? 17 O K. N. Crabtree et al. 2013, Science, 342, 1354 -1357 F