High resolution molecular beam study of the origin band of the B̃ 2Σ+–X̃ 2Σ+ system of yttrium imide

Abstract

The (0,0,0)–(0,0,0) band of the B̃ 2Σ+–X̃ 2Σ+ system of three isotopomers of yttrium imide (Y14NH, Y15NH, and Y14ND) has been studied by laser-induced fluorescence in a molecular beam apparatus. Rotational, fine, and nuclear magnetic hyperfine structures have been resolved and analyzed. The B̃ 2Σ+(0,0,0) state of Y14NH, Y14ND, and Y15NH is severely perturbed below J=30.5 by eight, three, and two vibronic states, respectively. Although, the nature of these perturbing states can only be speculated upon, their symmetries are either Σ2 or Π2, and this has made it possible to deperturb the B̃ 2Σ+ state successfully. The spectra can be reproduced within 140 MHz (0.0047 cm−1). The analyses confirm that the molecule is linear in both states with the nuclear arrangement Y–N–H. The bond lengths in the ground X̃ 2Σ+ state and the B̃ 2Σ+ state have been derived to be rY–N=1.877 57(13) Å, rN–H=1.0067(10) Å, and rY–N=1.8839(43) Å, rN–H=1.242(30) Å, respectively. The results are compared with the values of ab initio calculations on YNH and YN, and the experimental data on YN and YO. The atomic character of the unpaired electron in the ground state is 58% Y + 5s and 42% Y + 5p. The electron configurations for the ground X̃ 2Σ+ state and the B̃ 2Σ+ state are discussed and compared with ab initio calculations whenever possible.

Spectroscopic Investigation of the Electronic Structure of YN: The X1Σ+ Ground State and the New B1, C1 and D1 Excited Electronic States

“…The experimental conditions were similar to those used in our investigation of YNH (9). A rotating yttrium rod (Goodfellow, 99.9%) was ablated with the third harmonic beam (354.7 nm, 10-20 mJ/pulse) of a Nd:YAG laser (Lumonics, YM200) focused to an ∼1 mm 2 spot in the presence of He carrier gas doped with ∼1-2% NH 3 ( 14 NH 3 , Matheson; 15 NH 3 , MSD Isotopes, 95% 15 N).The He gas containing the YN molecules and other products of the yttrium plasma reaction with ammonia expanded into vacuum, cooling the internal degrees of freedom of the molecules.…”

Solvation of Yttrium with Ammonia: An Experimental and Theoretical Study

“…The binding energies for the YNH(NH 3 ) n-1 + NH 3 f YNH-(NH 3 ) n reaction are reported in Table 4. In all cases, the products of the reaction are more stable than the reactants.…”

“…The ammonia molecules lie essentially at 90°from the YNH axis. The H 3 N-Y-NH 3 angle is essentially 180°, 120°, and 90°in the YNH(NH 3 ) 2 , 3 ) n with n ) 0, 1, 2, 3 …”

“…YNH(NH 3 ) 3 , and YNH(NH 3 ) 4 complex, respectively (see Table 1). Therefore, the corresponding overall geometries are Tshaped, trigonal pyramidal, and square pyramidal.…”

“…It is known that yttrium imide is formed readily when ammonia is introduced in the plasma resulting from the laser vaporization of yttrium, but this may result from ion, excited states, or high-temperature chemistry. 3,4 Here, we demonstrate that indeed neutral yttrium atoms thermalized at 300 K react with ammonia to produce YNH. In addition, we show that further interactions with ammonia lead to the solvation of YNH rather than additional oxidative addition.…”