Microwave Spectrum of the SD+3 Ion: Molecular Structure

Area of Science:

• Molecular Spectroscopy
• Quantum Chemistry
• Astrochemistry

Background:

• The sulfonium radical ion (SH+3) and its deuterated analog (SD+3) are important in interstellar chemistry.
• Understanding their precise molecular structures is crucial for interpreting astronomical observations.

Purpose of the Study:

• To accurately measure the spectral lines of the SD+3 ion.
• To determine the rotational and centrifugal distortion constants for SD+3.
• To derive the precise molecular structures (rz and re) of SH+3 and SD+3.

Main Methods:

• Measurements of J = 1-0 to 4-3 spectral lines of SD+3 in the 152-610 GHz region.
• Generation of the SD+3 ion using a hollow-cathode discharge in a D2S and D2 gas mixture.
• Source-modulated microwave spectroscopy in a free space absorption cell.

Main Results:

• Determined rotational constant B0 and centrifugal distortion constants DJ and DJK for SD+3.
• Derived the rz structures of SH+3 (rz = 1.36512(22) Å, thetaz = 94.098(26)°) and SD+3 (rz = 1.36086(16) Å, thetaz = 94.1211(195)°).
• Estimated the re structure of SH+3 (re = 1.35001(113) Å, thetae = 94.181(135)°) based on structural shifts.

Conclusions:

• The study provides precise structural parameters for SH+3 and SD+3 ions.
• These findings contribute to a better understanding of the properties and behavior of these molecular ions in various chemical environments.
• The derived structures are valuable for theoretical calculations and astrophysical modeling.