Molecular g Values, Magnetic Susceptibility Anisotropies, Molecular Quadrupole Moments, and the Second Moment of the Electronic Charge Distribution in OCF2, CH2CF2, cis-CHFCHF, and CH2F2

Abstract

The rotational molecular Zeeman effect is observed under high resolution and high magnetic fields in OCF2, CH2CF2, cis-CHFCHF, and CH2F2. The absolute values of the molecular g values (gaa, gbb, and gcc) and the signs and magnitudes of the magnetic susceptibility anisotropies [(2χaa − χbb − χcc) and (2χbb − χaa − χcc)] in the principal inertial axes are obtained and listed. Arguments are presented to show that all molecular g values are negative leading to the molecular quadrupole moments. For ease of comparison, the values are given below in an arbitrary x, y, and z axis system. The x and y axes are in the heavy-atom molecular plane, and the x axis bisects the FCF angle in all of the molecules. The units of χ are 10−6 erg/G2·mole and the units of Qxx are 10−26 esu·cm2. OCF2CH2=CF2cis-CHF=CHFH2CF2gxx− (0.0568 ± 0.0006)− (0.0421 ± 0.0005)− (0.0296 ± 0.0003)− (0.0411 ± 0.0004)gyy− (0.0747 ± 0.0004)− (0.0466 ± 0.0004)− (0.1015 ± 0.0009)− (0.0725 ± 0.0006)gzz− (0.0328 ± 0.0006)− (0.0119 ± 0.0004)− (0.0158 ± 0.0002)− (0.0398 ± 0.0004)(2χxx − χyy − χzz)+ (1.6 ± 0.9)− (2.3 ± 0.6)− (1.6 ± 0.3)+ (0.8 ± 0.4)(2χyy − χxx − χzz)+ (5.3 ± 0.6)+ (7.7 ± 0.5)+ (5.7 ± 0.4)− (3.9 ± 0.5)Qxx− (3.7 ± 0.7)+ (2.4 ± 0.5)+ (3.0 ± 0.3)+ (1.9 ± 0.3)Qyy− (0.2 ± 0.5)− (0.9 ± 0.4)− (1.7 ± 0.4)− (4.1 ± 0.4)Qzz+ (3.9 ± 1.1)− (1.5 ± 0.8)− (1.3 ± 0.5)+ (2.2 ± 0.6) The diagonal elements in the paramagnetic susceptibility tensor and the anisotropies in second moment of the electronic charge distributions are computed from the above results and the known molecular structures. The above results are used along with additivity relations for the second moment of the electronic charge distribution to give estimates of the diamagnetic and total magnetic susceptibility tensor elements.