The Rotational Zeeman Effect of 1,2,4-Trifluorobenzene

Abstract

on the Occasion of his 65 th BirthdayThe rotational Zeeman effect of 1,2,4-trifluorobenzene has been studied for 8 low-J rotational transitions in magnetic fields between 1.9 and 2.4 Tesla. The observed susceptibility anisotropics and molecular ^/-values are: (2/aa-^b()-x cc) = 37.85(69) • 10~6 erg G~2 mole" \ (2xbb--/.cc-x aa) = 56.85(54)-IO'"6 erg G "2 mole"1, gaa= -0.0393(3), ^"=-0.0277(3), and gcc = 0.0042(2). The Zeeman parameters have been used to derive the molecular electric quadrupole moments and vibronic ground state expectation values for the electronic second moments. The observed out-ofplane quadrupole moment is discussed with reference to an additivity scheme proposed earlier. The observed out-of-plane component of the molecular magnetic susceptibility tensor is in excellent agreement with the value predicted earlier from the CNDO/2-7i-electron density alternation at the ring atoms.