Experimental determination of spin–orbital coupling states of O<sub>2</sub>(−)

Only one electron affinity of oxygen, 43(1) kJ mol -1 is generally cited since the molecular orbital theory anion bond order [3/4] gives an electron affinity, 14 kJ mol -1 . However, electron correlation rules predict 27 bonding and 27 antibonding spin orbital coupling states. The relative bond orders (RBOs), 12/13 to [1/ 4] and the 13 valence electrons of superoxide are used to calculate electron affinities 103 to -243 kJ mol -1 consistent with experimental and theoretical values. These are used to construct 54 ionic Morse potentials.Chemistry students are taught that Lewis electron pair theory incorrectly predicts a singlet ground state for O 2 while Mulliken's molecular orbital theory and Pauling's three electron bonds predicts a triplet ground state. Their relative bond order (RBO), RBO = [(4 -1)/4] = [3/4] gives one positive electron affinity E a (O 2 ) = E a (O) -D e (O 2 ) (1 -RBO) = 14 kJ mol -1 . In 1973, Krauss et al. observed: ''The experimental and theoretical understanding of the excited states of O 2 -is very limited. Simple electron correlation rules determine that 24 energy curves arise from the interaction of ground state O( 3 PThe E a (O 2 ), 105, 90, 75, 55, and 30 kJ mol -1 determined from the Born Haber cycle, charge transfer complex absorption, and reduction potentials, ERED, were confirmed by electron capture detector (ECD) and other gas phase data. The ground state AE a (O 2 ), 106 kJ mol -1 was determined from the electron impact of NO 2 and two other methods. However, the theoretical and experimental E a (O 2 ) 108 to -800 kJ mol -1 in the National Institute of Standards and Technology website are benchmarked to the E a (O 2 ), 43(1) kJ mol -1 from negative ion photoelectron spectra, NPES. In 2006, this laboratory recognized the 24 primary states give rise to (6 9 9) = 54 [O -( 2 P)(6) ? O( 3 P) (9)] spin states. We reported 27 new E a (O 2 ), 13-103 kJ mol -1 from pulsed discharge electron capture detector (PDECD) data and identified peaks in the negative ion photoelectron spectra, NPES-95 at these energies. Here, we show literature data are consistent with these values as illustrated in Fig. 1 [4 -12].In 1993, Ohsaka et al. reported entropy changes for reduction, -DS et , from slopes of ERED versus T in aprotic solvents [13]. The slope for hexamethylphosphoramide gives a -DS et , 67.7 J mol -1 K -1 , equal to the Trouton's Rule entropy of vaporization while that for dimethyl sulfoxide gives an apparent -DS et , 133 J mol -1 K -1 . Over the past 2 years, Sunil Pai followed Ohsaka and measured nearly 100 CV for O 2 in dimethyl sulfoxide from 273 to 409 K as a part of his 2011 INTEL finalist paper, some of which are shown in Fig. 1. The ERED are calibrated to -DS et , 67.7 J mol -1 K -1 and the E a for the ''X'' state. The other ERED versus T plots give slopes, -DS et 0.0 to

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“…Here, we show literature data are consistent with these values as illustrated in Fig. 1 [4][5][6][7][8][9][10][11][12].…”

supporting

confidence: 88%

“…Experimental data giving the 27 spin states of superoxide from[4,[6][7][8][9][10][11]. Electrochemical data for O 2 from this work and[13].…”

mentioning

confidence: 86%

Paradigms and paradoxes: what are the 54 electron affinities of O2?

Chen

Anderson³

et al. 2011

Struct Chem

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“…The procedures for the calculation of the HIMPEC in Figure 1 have been previously described in detail. The curves for the diatomic molecules are presented for comparison with HIMPEC for guanine from this work [5,6,11,12,14,16].…”

Section: Experiments and Calculationsmentioning

confidence: 99%

“…We reported AE a (C,U,T) from the onsets identified using reduction potentials. These are shown in Figure 2 [5,[7][8][9][10][11][12][13][14][15][16][17][18][19]. Water molecules (10-15) will complete the inner hydration shell for C, U, and T anions based on the experimental sequential hydration energy, 0.20(5) eVand the bulk hydration energy of 2.34 eV.…”

Section: Molecular Simulation 721mentioning

confidence: 99%

“…Significantly different electron affinities were identified: (in eV) O 2 , 0.05(2)-1.07 (2); NO, 0.02(1)-0.91(10); Watson -Crick adenine -thymine (AT), 1.4(1); G, 1.66(2), 0.3(1); A, 1.10(2), 0.3(1), 0.02(1); C, 1.04(2), 0.77(2), 0.230(8), 0.216(1), 0.13 (12), 0.098(1), 0.085(8); U, 1.00(2), 0.80(5), 0.50(5), 0.30(5), 0.15 (12), 0.090(6); T, 0.99(1), 0.80(5), 0.50(5), 0.30(5), 0.12 (12), 0.068 (8). Twenty-seven E a (O 2 ) were assigned to predicted doublet and quartet states.…”

Section: Introductionmentioning

confidence: 99%

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The role of spin in biological processes: O₂, NO, nucleobases, nucleosides, nucleotides and Watson–Crick base pairs

Chen

2009

Molecular Simulation

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The experimental electron affinities of adenine, guanine, cytosine, thymine and uracil have been determined from reduction potentials and negative ion photoelectron spectra. Updated values for purine, pyrimidine and other nitrogen heterocyclics, which have not been measured in the gas phase, are presented. The electron affinity of Watson -Crick guanine -cytosine is estimated empirically. The experimental values are consistent with quantum mechanical semi-empirical multiconfiguration configuration interaction calculations. The bulk hydration energies of the nucleobase anions, 2.34 eV, determined from the experimental data and sequential anion hydration energy difference of about 0.20(5) eV suggest that 10 -15 water molecules complete the hydration shell. The electron affinities for the formation of doublet and quartet anions of the nucleobases, nucleosides, nucleotides and Watson -Crick base pairs are calculated. We postulate that low-lying quartet anion states and their spin distribution can and will participate in electron conduction, radiation damage, oxidation damage and repair, strand breakage and protein synthesis.

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Atmospheric pressure anion mass spectrometry: electron affinities and activation energies of thermal electron attachment – perfluoromethylcyclohexane, C₇F₁₄

Chen

Barrera

et al. 2015

Rapid Comm Mass Spectrometry

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There are multiple anions of c-C6 F11 -CF3 more stable than the neutral. Electron-capture detection and atmospheric pressure negative ion mass spectrometry are effective general methods for determining multiple electron affinities similar to the photodetachment, flowing afterglow, magnetron, negative surface ionization, swarm and beam procedures. Semi-empirical theoretical calculations support experimental results. Additional mass analysis studies of reactions of c-C6 F11 -CF3 with electrons over a wide range of temperatures, pressures and electron energies are desirable.

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Experimental determination of spin–orbital coupling states of O₂(−)

Cited by 14 publications

References 44 publications

Paradigms and paradoxes: what are the 54 electron affinities of O2?

Paradigms and paradoxes: what are the 54 electron affinities of O2?

The role of spin in biological processes: O₂, NO, nucleobases, nucleosides, nucleotides and Watson–Crick base pairs

Atmospheric pressure anion mass spectrometry: electron affinities and activation energies of thermal electron attachment – perfluoromethylcyclohexane, C₇F₁₄

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Experimental determination of spin–orbital coupling states of O2(−)

Cited by 14 publications

References 44 publications

Paradigms and paradoxes: what are the 54 electron affinities of O2?

Paradigms and paradoxes: what are the 54 electron affinities of O2?

The role of spin in biological processes: O2, NO, nucleobases, nucleosides, nucleotides and Watson–Crick base pairs

Atmospheric pressure anion mass spectrometry: electron affinities and activation energies of thermal electron attachment – perfluoromethylcyclohexane, C7F14

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Experimental determination of spin–orbital coupling states of O₂(−)

The role of spin in biological processes: O₂, NO, nucleobases, nucleosides, nucleotides and Watson–Crick base pairs

Atmospheric pressure anion mass spectrometry: electron affinities and activation energies of thermal electron attachment – perfluoromethylcyclohexane, C₇F₁₄