Photoionization studies of (BH3)n (n= 1,2)

Article abstract of DOI:10.1063/1.454569

The results of photoionization mass spectrometric studies on B2H6, and BH3 ( produced by pyrolysis of B2H6) are presented.The photoion yield curves of B2Hn⁺ (n = 2-6) and BHn⁺ (n = 2-3) from B2H6, as well as BHn+ (n = 1-3) from BH3 have been obtained.It is shown that the combination of appearance potential measurements for BH3⁺ (B2H6) and BH3⁺ (BH3) yields a poor upper limit for -ΔH _{dimerization,0 K} (BH3) of 52.7 kcal/mol, while the combination of BH2⁺ (B2H6) and BH2⁺ (BH3) provides a better upper limit (46.6+/-0.6 kcal/mol) for this quantity.However, the threshold for BH⁺ (BH3), combined with auxiliary data, provides the best current experimental value, ( 34.3-39.1 )+/-2 kcal/mol.This experimental value is in good agreement with a recent ab initio calculation, and is arrived at by using the best current estimate of ΔH_f(B2H6), rather than a radically different value proposed in that paper.The ionization potential of BH3, ΔH_f (BH2⁺), and the atomization energy of BH3 obtained experimentally are in excellent agreement with other ab initio calculations.The upper limits on heats of formation for the ionic species B2Hn⁺ ( n = 2-6) are obtained, and plausible structures are discussed for these species, based on the current energetics and various ab initio calculations.Finally, the fragmentation behavior of photoions from diborane is shown to have a more facile explanation by quasiequilibrium theory than by a molecular orbital picture, with the probable exception of BH3⁺ (B2H6).

Full text of DOI:10.1063/1.454569

Photoionization studies of (BH3) n (n=1,2)
B. Ruščić, C. A. Mayhew, and J. Berkowitz
Citation: The Journal of Chemical Physics 88, 5580 (1988); doi: 10.1063/1.454569
View online: http://dx.doi.org/10.1063/1.454569
View Table of Contents: http://scitation.aip.org/content/aip/journal/jcp/88/9?ver=pdfcov
Published by the AIP Publishing
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This article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http://scitation.aip.org/termsconditions. Downloaded to IP:
128.135.12.127 On: Thu, 09 Oct 2014 14:33:07

This article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http://scitation.aip.org/termsconditions. Downloaded to IP:
128.135.12.127 On: Thu, 09 Oct 2014 14:33:07

This article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http://scitation.aip.org/termsconditions. Downloaded to IP:
128.135.12.127 On: Thu, 09 Oct 2014 14:33:07

This article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http://scitation.aip.org/termsconditions. Downloaded to IP:
128.135.12.127 On: Thu, 09 Oct 2014 14:33:07

This article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http://scitation.aip.org/termsconditions. Downloaded to IP:
128.135.12.127 On: Thu, 09 Oct 2014 14:33:07

This article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http://scitation.aip.org/termsconditions. Downloaded to IP:
128.135.12.127 On: Thu, 09 Oct 2014 14:33:07

This article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http://scitation.aip.org/termsconditions. Downloaded to IP:
128.135.12.127 On: Thu, 09 Oct 2014 14:33:07

This article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http://scitation.aip.org/termsconditions. Downloaded to IP:
128.135.12.127 On: Thu, 09 Oct 2014 14:33:07

This article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http://scitation.aip.org/termsconditions. Downloaded to IP:
128.135.12.127 On: Thu, 09 Oct 2014 14:33:07

This article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http://scitation.aip.org/termsconditions. Downloaded to IP:
128.135.12.127 On: Thu, 09 Oct 2014 14:33:07

This article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http://scitation.aip.org/termsconditions. Downloaded to IP:
128.135.12.127 On: Thu, 09 Oct 2014 14:33:07