The rotational spectra, potential function, Born-Oppenheimer breakdown, and magnetic shielding of SnSe and SnTe

Abstract

The pure rotational spectra of 27 isotopic species of SnSe and SnTe have been measured in the frequency range of 5-24 GHz using a Fabry-Perot-type resonator pulsed-jet Fourier-transform microwave spectrometer. Gaseous samples of both chalcogenides were prepared by laser ablation of suitable target rods and were stabilized in supersonic jets of Ar. Global multi-isotopolog analyses of all available high-resolution data produced spectroscopic Dunham parameters Y01, Y11, Y21, Y31, Y02, and Y12 for both species, as well as Born-Oppenheimer breakdown (BOB) coefficients delta01 for Sn, Se, and Te. A direct fit of the same data sets to an appropriate radial Hamiltonian yielded analytic potential energy functions and BOB radial functions for the X 1Sigma+ electronic state of both SnSe and SnTe. Additionally, the magnetic hyperfine interaction produced by the dipolar nuclei 119Sn, 117Sn, 77Se, and 125Te was observed, yielding first determinations of the corresponding spin-rotation coupling constants.

The 115Sn, 117Sn and 119Sn nuclear spin-rotation constants in stannous monoxide, SnO, and a new multi-isotopomer analysis

“…The absolute shielding scale for tin, put forward by Laaksonen and Wasylishen, places the absolute shielding constants for compounds of the type SnX 4 , X = H, Cl, CH 3 , in the region of 2100-2700 ppm. Our results also compare well with those shielding parameters determined by Bizzocchi et al for SnSe and SnTe [19].…”

“…Here D is the dipole moment of SnO, D = 4.32(10) D [2], and g J is the rotational g-factor for SnO, g J = À0.1623(5) . The values obtained are given in Table 6 and compared to the values from the other Snchalcogenides [19,29].…”

Rotational spectra, potential function, Born–Oppenheimer breakdown and magnetic shielding of SiSe and SiTe

“…The instrument utilises the coaxially oriented beam resonator arrangement (COBRA) [13,14], and is equipped with a laser-ablation pulsed molecular beam source with DC-discharge capabilities as already described in a preceding paper [15]. The solid samples were prepared using fine powder of the pure chalcogen (selenium or tellurium); the rod was formed by pressing the solid mixture, containing a small amount of an acrylic-acid based glue, onto a central stainless steel pin [15,16]. The pulsed beam of the Nd:YAG-laser (k = 1064 nm, 500 mJ pulse À1 ) is focused onto the rod and ablates metal atomic vapours at a repetition rate of 20 Hz.…”

“…The pulsed beam of the Nd:YAG-laser (k = 1064 nm, 500 mJ pulse À1 ) is focused onto the rod and ablates metal atomic vapours at a repetition rate of 20 Hz. Highly diluted silane (SiH 4 1%) in Argon (purity 3.5, 2-4 bar stagnation pressure) is injected from the back and the resulting gaseous mixture is then subjected to a DC-electric discharge inside the 3 mm channel of the nozzle prior to the expansion into the Fabry-Pérot type resonator of the FT-MW spectrometer [15]. Typically, applied DC voltages are 500-1500 V which correspond to average discharge currents of 300-1000 lA.…”

“…The analyses reported here for SiSe and SiTe were performed using LeRoy's DPOTFIT 1.1 programme [27], and using the same model successfully employed for the DPF of the spectroscopic data of tin [15] and lead chalcogenides [28]: V ð1Þ ad ðrÞ is the ''extended Morse oscillator" EMO 1 (3,3) potential function…”