We report millimeter-wave measurements of the rotational spectrum of sulfine (CH2SO) in the 60–90 GHz region. Eight ground-state rotational transitions with Ka = 0, 1, and 2 were recorded using the Argonne Chirped-Pulsed Fourier Transform millimeter-Wave spectrometer, with CH2SO generated by oxidation of dimethyl sulfide at 1500 K. The observed line centers show systematic offsets of approximately 300–460 kHz relative to the predictions of the earlier measurements limited to frequencies below 26 GHz by Penn and Olsen. A combined fit of the present data with previously published transitions using Watson's S-reduction Hamiltonian in the Ir representation yields improved spectroscopic constants. The updated parameters predict transition frequencies in the millimeter and submillimeter regions with significantly reduced uncertainties, facilitating future astronomical searches for sulfine in the interstellar medium.
We describe the design and implementation of SURF (Spectroscopy User and Research Framework), an open-source, Python-based control and automation interface for the L-shaped Fourier transform microwave spectrometer (L-FTMW) at Tennessee Tech University. The L-FTMW combines high-resolution Fabry–Perot cavity and broadband chirped-pulse spectroscopy techniques in a single instrument; SURF currently provides graphical control of all supported instrument functions of the cavity subsystem. The software is organized into three layers that separate device communication, instrument coordination, and the graphical user interface. Six device-specific Python controller classes (in their own modules) manage the microwave synthesizer, arbitrary waveform generator, cavity tuning actuator, digital delay generators, oscilloscope, and microwave routing switch, while a central spectrometer class composes these modules into complete measurement routines. A PySide6 (Qt-based) graphical interface – kept responsive during long measurements by running acquisitions asynchronously in the background – exposes these routines through task-oriented tabs for cavity mode mapping, automated frequency scanning, manual device control, and spectral analysis, with live plotting and progress reporting throughout. Experiment configurations are stored in human-readable, schema-validated TOML files and automatically archived with every scan to support reproducibility. We discuss the design decisions, the development workflow, spectral validation, and the features intended to ease adaptation of the framework to other cavity FTMW instruments. SURF has operated reliably in both research and teaching-laboratory settings, where it enables students with no prior instrumentation experience to record rotational spectra.
