Extrapolated difference technique for the determination of atomization energies of Sm, Eu, and Yb bromides

• Vaporization of LnBr3–GdBr3 and LnBr2–BaBr2 (Ln: Sm, Eu, Yb) systems was studied.
• Ionization efficiency curves for fragment M+ ions were measured.
• Extrapolated difference technique was developed for determination of atomization energies.
• Atomization energies of LnBr3 and LnBr2 (Ln: Sm, Eu, Yb) molecules were determined.

An approach for the determination of atomization energies based on the extrapolated difference technique in the framework of Knudsen effusion mass spectrometry is proposed. Its essence is the use of thermodynamic data for the determination of the appearance energy of fragment ions of a reference and a special mathematical treatment of the ionization efficiency functions. The advantages of this approach are demonstrated for the cases of incongruently vaporizing lanthanide bromides that suffer from decomposition or disproportionation at high temperatures. The atomization energies for SmBr2 (7.78 ± 0.12 eV), EuBr2 (7.51 ± 0.11 eV), YbBr2 (7.25 ± 0.13 eV), SmBr3 (11.09 ± 0.10 eV), and YbBr3 (10.23 ± 0.09 eV) molecules have been determined for the first time.

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