A Molecular Hydrogen Production Model from Li and LiH in the Early Universe


Neutral isotopes and ions of H, He and Li define the chemistry of the early universe by collisional and radiative process, where under low temperature and radiation regime, only neutral species were essential in the cooling mass that gave origin to the first proto star structures. Nevertheless, up to now, in every kinetic model Li is permanently discarded from fundamental reactions due to its extremely low density. Contrarily to these previous models we have developed a novel kinetic model based on two consecutive reactions of Li and LiH with H, in order to generate a recursive process that fit well H2 production to temperatures as low as 200 K, according to the cosmological time at the end of the dark epoch. Our results show how Li and LiH merge as first catalyzers of the H to H2 chemical reaction and permit us to explain the expected abundance of H2 as the main coolant in the early universe as well as in cold regions of the cosmos.

Share and Cite:

R. Morales and M. Canales, "A Molecular Hydrogen Production Model from Li and LiH in the Early Universe," International Journal of Astronomy and Astrophysics, Vol. 3 No. 2, 2013, pp. 108-112. doi: 10.4236/ijaa.2013.32012.

Conflicts of Interest

The authors declare no conflicts of interest.


[1] P. J. E. Peebles, “Principles of Physical Cosmology,” Princeton University Press, Princeton, 1993.
[2] S. Weinberg, “The First Three Minutes: A Modern View of the Origin of the Universe,” Published by Basic Books, Perseus Books Group, New York, 1993.
[3] A. Dalgarno, “The Growth of Molecular Complexity in the Universe,” Faraday Discussions, Vol. 133, 2006, pp. 9-25. doi:10.1039/b605715b
[4] D. Galli and F. Palla, “The Chemistry of the Early Universe,” Astronomy & Astrophysics, Vol. 335, 1998, pp. 403-423.
[5] S. Bobino, M. Tacconi, F. A. Gianturco, D. Galli and F. Palla, “On the Relative Abundance of LiH and LiH+ Molecules in the Early Universe: New Results from Quantum Reactions,” Astrophysical Journal, Vol. 731, 2011, p. 107. doi:10.1088/0004-637X/731/2/107
[6] M. Tegmark, J. Silk, M. J. Rees, A. Blanchard, T. Abel and F. Palla, “How Small Were the First Cosmological Objects?” Astrophysical Journal, Vol. 474, No. 1, 1997, pp. 1-12. doi:10.1086/303434
[7] P. C. Stancil, S. Lepp and A. Dalgarno, “The Lithium Chemistry of the Early Universe,” Astrophysical Journal, Vol. 458, No. 401, 1996, pp. 401-406. doi:10.1086/176824
[8] P. C. Stancil and A. Dalgarno, “Stimulated Radiative Association of Li and H in the Early Universe,” Astrophysical Journal, Vol. 479, No. 2, 1997, pp. 543-546. doi:10.1086/303920
[9] T. de Jong, “The Density of H2 Molecules in Dark Interstellar Clouds,” Astronomy & Astrophysics, Vol. 20, 1972, pp. 263-274.
[10] E. Bodo, F. A. Gianturco and R. Martinazzo, “The GasPhase Lithium Chemistry in the Early Universe: Elementary Processes, Interaction Forces and Quantum Dynamics,” Physics Reports, Vol. 384, No. 3, 2003, pp. 85-119. doi:10.1016/S0370-1573(03)00243-6
[11] J. Larena, J. M. Alimi and A. Serna, “Big Bang Nucleosynthesis in Scalar Tensor Gravity: The Key Problem of the Primordial 7Li Abundance,” Astrophysical Journal, Vol. 658, No. 1, 2007, pp. 1-10. doi:10.1086/511028
[12] I. Levine, “Physical Chemistry,” 5th Edition, McGraw Hill, New York, 2005.
[13] P. Atkins and J. De Paula, “Physical Chemistry,” 8th Edition, Oxford University Press, New York, 2006.
[14] H. Margenau and G. M. Murphy, “The Mathematics of Physics and Chemistry,” Editorial Van Nostrand, 1956.
[15] S. Lepp, P. C. Stancil and A. Dalgarno, “Atomic and Molecular Processes in the Early Universe,” Journal of Physics B: Atomic, Molecular and Optical Physics, Vol. 35, No. 10, 2002, pp. R1-R24. doi:10.1088/0953-4075/35/10/201
[16] O. J. Bennet, A. S. Dickinson, T. Leininger and F. X. Gadea, “Radiative Association in Li+H Revisited: The Role of Quasi-Bound States,” Monthly Notices of the Royal Astronomical Society, Vol. 341, No. 1, 2003, pp. 361-368. doi:10.1046/j.1365-8711.2003.06422.x
[17] L. J. Dunne, J. N. Murrell and P. Jemmer, “Analytical Potential Energy Surface and Quasi-Classical Dynamics for the Reaction LiH(X,1?+)+H(2S) > Li(2S)+H2(X,1? g+),” Chemical Physics Letters, Vol. 336, No. 1-2, 2001, pp. 1-6. doi:10.1016/S0009-2614(01)00102-6
[18] H. Mizusawa, K. Omukai and R. Nishi, “Primordial Molecular Emission in Population III Galaxies,” Publication of the Astronomy Society of Japan, Vol. 57, 2005, pp. 951-967.
[19] J. P. Prieto, P. Padoan, R. Jimenez and L. Infante, “Population III Stars from Turbulent Fragmentation at Redshift 11,” Astrophysics Journal, Vol. 731, 2011, p. L38. doi:10.1088/2041-8205/731/2/L38
[20] T. Abel, P. Anninos, Y. Zhang and M. L. Norman, “Modeling Primordial Gas in Numerical Cosmology,” New Astronomy, Vol. 2, No. 3, 1997, pp. 181-207. doi:10.1016/S1384-1076(97)00010-9
[21] M. Canales and R. G. E. Morales, “A Kinetic Model for H2 Formation from Li in Pre-stellar Atmospheres,” Proceedings of the 7th Congress of Chilean Environmental Chemistry and Physics—Atmospheric Section, Concepción, 20-22 October 2011, p. 2.
[22] V. Bromm, P. S. Coppi and R. B. Larson, “The Formation of the First Stars. I. The Primordial Star-forming Cloud,” Astrophysical Journal, Vol. 564, No. 1, 2002, pp. 23-51. doi:10.1086/323947

Copyright © 2020 by authors and Scientific Research Publishing Inc.

Creative Commons License

This work and the related PDF file are licensed under a Creative Commons Attribution 4.0 International License.