Reactions of beryllium atoms with hydrogen. Matrix infrared spectra of novel product molecules
作者:Thomas J. Tague、Lester Andrews
DOI:10.1021/ja00078a057
日期:1993.12
Beryllium atoms formed by pulsed laser ablation have been codeposited with gaseous mixtures of hydrogen diluted in argon (concentrations varied from 25:1 to 100:1) onto a substrate at 10 K. Infrared spectroscopy on the reaction mixture identified six novel product molecules-BeH, BeH2, BeBeH, HBeBH, HBeHBeH, and HBe(H)2-BeH. Assignments of infrared absorption bands were made on the basis of broad-band photolysis and annealing behavior, isotopic substitutions, and ab initio calculations performed at the MBPT(2) level. The major products initially are BeH (1970.0 cm-1) and the previously unobserved BeH2 molecule (upsilon3 = 2159.1 cm-1, upsilon2 = 697.9 cm-1) with formation of the three dimers HBeBeH, HBeHBeH, and HBe(H)2BeH at the expense of the initial reaction products upon annealing of the matrix to 30 K. The former dimer involves a stable Be-Be bond, and the latter dimers incorporate bridging hydrogen atoms. The new Be2H molecule (2013.7, 540.0 cm-1) is a minor product in these experiments, which exhibits a stronger Be-Be bond than Be2.