The ground-state ionization potential of the He4 atom is found to be 5 945 204 223 (42) MHz. Along with lower-order contributions, this result includes all effects of relative order alpha4, alpha(3)m(e)/m(alpha), and alpha(5)ln(2)alpha. Effective operators derived in dimensionally regularized nonrelativistic quantum electrodynamics are employed. The average values of these operators are evaluat...

Using a time-dependent density-functional-theory (TDDFT) method that incorporates the exact exchange, we reproduce the measured ionization suppression for vanadium in 1500-nm lasers of 1.4 to 2.8 × 1013 W/cm2. The calculated ionization yields are 0.07 to 0.5 in 100 fs sin2 pulses. For weaker laser intensities a method with more configurations is needed to properly describe the multiphoton, rath...

The vacuum ultraviolet photoionization mass spectrum of As, is presented, from the ionization threshold to 600 A. The apparent adiabatic ionization potential is ~8.49 eV, but the true value may be significantly lower. Three broad autoionization features are observed, probably comprising members of a Rydberg series converging to the 3 ‘A, state of As:. The first fragment, Ass+, has an appearance...

We report here the development of a corona discharge (CD) initiated electrochemical (EC) electrospray ionization (ESI) technique using a standard electrospray ion source. This is a new ionization technique distinct from ESI, electrochemistry inherent to ESI, APCI, and techniques using hydroxyl radicals produced under atmospheric pressure conditions. By maximizing the observable CD at the tip of...