Millimeter‐wave rotational spectroscopy of MgOD and CaOD (X2Σ+)
摘要:
Pure rotational spectra of CaOD and MgOD have been recorded in the range 200–390 GHz using millimeter/sub-mm direct absorption spectroscopy. Transitions arising from the (000), (010), (020), and (100) modes have been measured for the 2Σ+ ground electronic states of these free radicals. The data were analyzed successfully using a linear 2Σ+ model for CaOD; for MgOD, only the (000) and (010) states could be fit with this Hamiltonian. Moreover, the (010) data required the addition of a substantial pΠ term to account for contamination of excited 2Π electronic states. For both species, the α2 vibration–rotation term was found to be negative, in contrast to MgOH and CaOH, suggesting a less anharmonic contribution to the bending potential in CaOD and MgOD. These measurements also indicate a shorter O–H bond in MgOH than the other alkaline earth hydroxide radicals, which likely results because this species is quasilinear.
The millimeter-wave spectrum of the MgOH radical (X 2Σ+)
作者:W.L. Barclay、M.A. Anderson、L.M. Ziurys
DOI:10.1016/0009-2614(92)85959-e
日期:1992.8
The pure rotational spectrum of the ground electronic state (X 2Σ+) of the MgOH radical has been observed using millimeter/sub-millimeter direct absorption spectroscopy, as well as that of MgOD, and the less abundant magnesium isotopically-substituted species 25MgOH and 26MgOH. The free radicals were created in a Broida-type oven by the reaction of metal vapor with hydrogen peroxide. The spin—rotation
High resolution spectroscopy of MgOH (X 2Σ+) in its V2 mode: Further evidence for quasilinearity
作者:A. J. Apponi、M. A. Anderson、L. M. Ziurys
DOI:10.1063/1.480455
日期:1999.12.22
Pure rotational spectraof the MgOH and MgOD radicals have been recorded in the v2bending vibration of their X 2Σ+ground electronic statesusing millimeter-wave direct absorption spectroscopy. Multiple rotational transitions arising from the v2l=11,22,20,31,33,42,and 44substates have been measured in the frequency range 240–520 GHz for these species. Both the spin-rotation and l-type doubling interactions have been resolved in the spectra. The complete data sets for MgOH and MgOD have been analyzed using a linear model for the Hamiltonian which takes into account higher order (l=±4)l-type interactions. The global analyses were adequate, but anomalous behavior was apparent in both molecules. In particular, the Bvvs v2relation was found to be highly nonlinear, large variations in the l-type doubling constant q were observed with vibrational level, and r0,rs,and r̃estructures determined differed substantially. Such findings suggest that MgOH is highly quasilinear,comparable to HNCO. The competition between ionic and covalent bonding is therefore becoming apparent in the lighter alkaline earth hydroxide species.