Selected ATcT [1, 2] enthalpy of formation based on version 1.122 of the Thermochemical Network [3]

This version of ATcT results was partially described in Ruscic et al. [4], and was also used for the initial development of high-accuracy ANLn composite electronic structure methods [5].

Species Name Formula Image    ΔfH°(0 K)    ΔfH°(298.15 K) Uncertainty Units Relative
TrihydrogenH(HH) (g, 2s 2A1' Ry)[H]1[H][H]1745.878743.094± 0.062kJ/mol3.02382 ±

Representative Geometry of H(HH) (g, 2s 2A1' Ry)

spin ON           spin OFF

Top contributors to the provenance of ΔfH° of H(HH) (g, 2s 2A1' Ry)

The 1 contributors listed below account for 94.8% of the provenance of ΔfH° of H(HH) (g, 2s 2A1' Ry).

Please note: The list is limited to 20 most important contributors or, if less, a number sufficient to account for 90% of the provenance. The Reference acts as a further link to the relevant references and notes for the measurement. The Measured Quantity is normaly given in the original units; in cases where we have reinterpreted the original measurement, the listed value may differ from that given by the authors. The quoted uncertainty is the a priori uncertainty used as input when constructing the initial Thermochemical Network, and corresponds either to the value proposed by the original authors or to our estimate; if an additional multiplier is given in parentheses immediately after the prior uncertainty, it corresponds to the factor by which the prior uncertainty needed to be multiplied during the ATcT analysis in order to make that particular measurement consistent with the prevailing knowledge contained in the Thermochemical Network.

Reaction Measured Quantity Reference
94.888.1 H(HH) (g, 2s 2A1' Ry) → H(HH) (g, 2p 2A2" Ry) ΔrH°(0 K) = 923.9 ± 5 cm-1Herzberg 1981, Herzberg 1980, Dabrowski 1980, Herzberg 1982, est unc

Top 10 species with enthalpies of formation correlated to the ΔfH° of H(HH) (g, 2s 2A1' Ry)

Please note: The correlation coefficients are obtained by renormalizing the off-diagonal elements of the covariance matrix by the corresponding variances.
The correlation coefficient is a number from -1 to 1, with 1 representing perfectly correlated species, -1 representing perfectly anti-correlated species, and 0 representing perfectly uncorrelated species.

Species Name Formula Image    ΔfH°(0 K)    ΔfH°(298.15 K) Uncertainty Units Relative
100.0 TrihydrogenH(HH) (g, Ry)[H]1[H][H]1745.878743.199± 0.062kJ/mol3.02382 ±
22.6 TrihydrogenH(HH) (g, 2p 2A2" Ry)[H]1[H][H]1756.931754.146± 0.015kJ/mol3.02382 ±
20.5 Trihydrogen cation[H3]+ (g)[H]1[H+][H]11110.3041106.696± 0.013kJ/mol3.02327 ±
20.5 Trihydrogen cation[H3]+ (g, para)[H]1[H+][H]11110.3041106.697± 0.013kJ/mol3.02327 ±
20.5 Trihydrogen cation[H3]+ (g, ortho)[H]1[H+][H]11110.5771106.695± 0.013kJ/mol3.02327 ±
2.4 Dioxidenium[HO2]+ (g)O[O+]1110.871107.98± 0.11kJ/mol33.00619 ±

Most Influential reactions involving H(HH) (g, 2s 2A1' Ry)

Please note: The list, which is based on a hat (projection) matrix analysis, is limited to no more than 20 largest influences.

Reaction Measured Quantity Reference
1.00088.1 H(HH) (g, 2s 2A1' Ry) → H(HH) (g, 2p 2A2" Ry) ΔrH°(0 K) = 923.9 ± 5 cm-1Herzberg 1981, Herzberg 1980, Dabrowski 1980, Herzberg 1982, est unc
1.00089.1 H(HH) (g, Ry) → H(HH) (g, 2s 2A1' Ry) ΔrH°(0 K) = 0 ± 0 cm-1triv

1   B. Ruscic, R. E. Pinzon, M. L. Morton, G. von Laszewski, S. Bittner, S. G. Nijsure, K. A. Amin, M. Minkoff, and A. F. Wagner,
Introduction to Active Thermochemical Tables: Several "Key" Enthalpies of Formation Revisited.
J. Phys. Chem. A 108, 9979-9997 (2004) [DOI: 10.1021/jp047912y]
2   B. Ruscic, R. E. Pinzon, G. von Laszewski, D. Kodeboyina, A. Burcat, D. Leahy, D. Montoya, and A. F. Wagner,
Active Thermochemical Tables: Thermochemistry for the 21st Century.
J. Phys. Conf. Ser. 16, 561-570 (2005) [DOI: 10.1088/1742-6596/16/1/078]
3   B. Ruscic and D. H. Bross,
Active Thermochemical Tables (ATcT) values based on ver. 1.122 of the Thermochemical Network (2016); available at
4   B. Ruscic,
Active Thermochemical Tables: Sequential Bond Dissociation Enthalpies of Methane, Ethane, and Methanol and the Related Thermochemistry.
J. Phys. Chem. A 119, 7810-7837 (2015) [DOI: 10.1021/acs.jpca.5b01346]
5   S. J. Klippenstein, L. B. Harding, and B. Ruscic,
Ab initio Computations and Active Thermochemical Tables Hand in Hand: Heats of Formation of Core Combustion Species.
J. Phys. Chem. A 121, 6580-6602 (2017) [DOI: 10.1021/acs.jpca.7b05945]
6   B. Ruscic,
Uncertainty Quantification in Thermochemistry, Benchmarking Electronic Structure Computations, and Active Thermochemical Tables.
Int. J. Quantum Chem. 114, 1097-1101 (2014) [DOI: 10.1002/qua.24605]

The aggregate state is given in parentheses following the formula, such as: g - gas-phase, cr - crystal, l - liquid, etc.

The listed uncertainties correspond to estimated 95% confidence limits, as customary in thermochemistry (see, for example, Ruscic [6]).
Note that an uncertainty of ± 0.000 kJ/mol indicates that the estimated uncertainty is < ± 0.0005 kJ/mol.

Website Functionality Credits
The reorganization of the website was developed and implemented by David H. Bross (ANL).
The find function is based on the complete Species Dictionary entries for the appropriate version of the ATcT TN.
The molecule images are rendered by Indigo-depict.
The XYZ renderings are based on Jmol: an open-source Java viewer for chemical structures in 3D.

This work was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences and Biosciences under Contract No. DE-AC02-06CH11357.