Precise Atomic-Mass Differences in the Region

A high-resolution mass spectrometer has been used to determine precise atomic-mass differences for 31 mass spectral doublets amongst the rare-earth chlorides. The precision of these determinations is in the range 0.6 μu to 3.8 μu, i.e. (2.5 to 25) × 10−9. The new data, when combined with previous data from this laboratory and with the known 37Cl–35Cl difference, provide mass-spectroscopically-derived connections between all naturally occurring odd-A nuclides from 141Pr to 169Tm and between all even-A nuclides from 142Nd to 170Er.