Determination of the first ionization potential of einsteinium by resonance ionization mass spectroscopy (RIMS)

• Published in: Journal of alloys and compounds Vol. 271; pp. 876 - 878
• Main Authors: Peterson, J.R., Erdmann, N., Nunnemann, M., Eberhardt, K., Huber, G., Kratz, J.V., Passler, G., Stetzer, O., Thörle, P., Trautmann, N., Waldek, A.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 12-06-1998
• Subjects: Einsteinium; First ionization potential; RIMS; First ionization potential; Einsteinium; RIMS
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/S0925-8388(98)00238-2

The first ionization potential of einsteinium (IP
Es) was determined by resonance ionization mass spectroscopy (RIMS) using samples with ≤10
12 atoms of
254Es (
T
1/2=276 days). This method is based on the measurement of photoionization thresholds as a function of applied electric field strength, followed by extrapolation to zero field strength to yield IP
Es. An atomic beam of Es was created by heating a filament on which einsteinium was electrodeposited from an aqueous solution onto a tantalum backing and covered with titanium metal. Es atoms were ionized via a three-step excitation scheme, and the ions mass-selectively detected in a time-of-flight (TOF) mass spectrometer. The excitation scheme used included a previously unknown EsI level at 32 924.9 cm
−1. Furthermore, an autoionizing state at 51 447.3 cm
−1 was also found. The first ionization potential of Es was determined to be 6.3676(5) eV (≡51 358(5) cm
−1).