Extension of Microwave Absorption Spectroscopy to 0.37-mm Wavelength

Abstract

High-resolution sweep spectroscopy has been extended to submillimeter wavelengths as short as 0.37 mm. The sensitivity of microwave spectroscopy in the submillimeter region (0.37 to 1 mm) has been improved by more than an order of magnitude. The highest-frequency spectral lines measured are the $J=6\mathrm{}\to 7$ transition of ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ at 806 651.719 MHz and the $J=66\mathrm{}\to 67$ transition of ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ ${}_{}{}^{32}{}_{}{}^{}\mathrm{S}$ at 813 353.706 MHz. The rotational constant $B_0$ for DF is observed to be 325 584.96 MHz.