Autoionization in I and I[sub 2] observed by multiphoton ionization and photoelectron spectroscopy: Two atomic iodine Rydberg series built on the ...5s[sup 2]5p[sup 4] [sup 3]P[sub 1] ion core and revised value for the I[sup +]([sup 3]P[sub 1]) limit.

Two well-developed Rydberg series of atomic iodine, built on the ...5s[sup 2]5p[sup 4] [sup 3]P[sub 1] ion core and assigned to nd[2][sub 5/2] and ns[1][sub 3/2] states with principal quantum numbers as high as n=47, have been observed by two photon (566≤λ≤600 nm) ionization of I(6s [sup 2]P[sub 3/2]), and time-of-flight photoelectron spectroscopy and mass spectrometry. The data reported here extend the nd[2][sub 5/2] and ns[1][sub 3/2] series by 27 and 23 terms, respectively. The limit for both series, 91 387.9±1.3 cm-1, revises upwards by 5.8 cm-1 the value for the I[sup +]([sup 3]P[sub 1]) state energy suggested by Minnhagen in 1962 [Ark. Fys. 21, 415 (1962)]. The quantum defects for the nd[2][sub 5/2] and ns[1][sub 3/2] series were determined to be 2.44±0.03 and 4.03±0.02, respectively. Several terms of a third, weaker series were also detected and tentatively assigned to nd[2][sub 3/2] states, also having the [sup 3]P[sub 1] ion core. Photoelectron peaks associated with direct, five photon ionization of I[sub 2] have been observed and are attributed to electronic autoionization of A [sup 2]Π[sub (3/2)u] ion core Rydberg states into the X [sup 2]Π[sub (1/2)g,(3/2)g] ionization continua. © 2003 American Institute of Physics. [ABSTRACT FROM AUTHOR]