New measurement of the fine structure in the 3 /sup 3/P state of /sup 4/He

The technique of level-crossing spectroscopy has been used to measure the fine-structure intervals in the 3 /sup 3/P state of /sup 4/He through the observation of the level crossings at 2277 and 3700 G. The magnetic fields at the crossing points were used in conjunction with calculated g values to obtain for the 3 /sup 3/P/sub 0/-3 /sup 3/P/sub 2/ fine-structure interval the value 8772.552 +- 0.040 MHz (4.5 ppm). These same data yielded for the lifetime of the 3 /sup 3/P state the value 97.6 +- 4.5 nsec and for the cross section for coherence-destroying collisions the value (718 +- 78) ..pi..a/sup 2//sub 0/.