The spin-rotation constants of the proton and tile fluorine nucleus in C

, Si

, Ge

, C

, Si

and Ge

were determined experimentally by the molecular beam magnetic resonance method. From the Hamiltonian and the high field approximation, the quantized energy level is given by the following equation. W

=-

H-

H-

, where

is one third of the trace of the C tensor. In the nuclear resonance experiment, the proton and the fluorine nuclear resonance curves consist of many unresolved lines given by v=-

H-

, and a Gaussian approximation is made to correlate

to the experimentally obtained half-width of the resonance curve. In the rotational resonance experiment, the five resonance peaks as predicted by v=-

H-

,

=0,

1 and

2, were all observed. The magnitude of car was determined by measuring the frequency distance between two adjacent peaks. The sign of

was determined by the side peak suppression technique. The technique is described, and the sign and magnitude of the spin-rotation constant cav are summarized as following: for C

-10.3

0.4tHz(from the rotational resonance), for SiH +3.71

0.08kHz(from the nuclear resonance), for Ge

+3.79

0.13kHz(from the nuclear resonance), for C

, -6.81

0.08kHz(from the rotational resonance), for Si

, -2.46

0.06kHz(from the rotational resonance), and finally for Ge

-1.84

0.04kHz(from the rotational resonance).onal resonance).esonance).