Radio Frequency Spectrum of the X 2π State of 7Li16O

The molecular beam electric resonance spectrum of the high temperature free radical 7Li16O is measured in areas of the region 5–12 350 MHz. ΔJ=0, ΔF=0, ±1 electric dipole transitions are observed in the Π3/22 and Π1/22 spin—orbit components of the ground electronic state. Transitions of the two lowest vibrational states are analyzed. The fine structure parameters are: v=0v=1AΠ−112.0(1) cm−1−108(1) cm−1〈 Π | (A/2+B)L+ | Σ 〉 〈 Π | BL+ | Σ 〉−139.3(2)cm−1−139.5(2.0) cm−1ωe800(100) cm−1μ6.84(3) D.The Frosch and Foley hyperfine parameters are: aΠ + 1/2 (bΠ + cΠ)3.98(1) MHz3.83(3) MHzaΠ − 1/2 (bΠ + cΠ)8.25(4) MHz6.76(8) MHzbΠ−19.67(14) MHz−20.2(5) MHzdΠ1.94(10) MHz1.65(3) MHz〈 Π | aL+ | Σ 〉−11.0(1.4) MHzeQq00.444(8) MHzeQq20.109(18) MHz.The observed fine structure constants are in excellent agreement with Van Vleck's model of pure precession and with detailed calculations of Wahl.