(2+1) REMPI spectra of the I2–Krand I2–N2van der Waals complexes and the (2+1[prime ]) ZEKE[ndash ]PFI photoelectron spectrum of I2+–Kr

Abstract

We present the (2 + 1) mass-resolved resonance-enhanced multiphoton ionisation (REMPI) spectrum of the [2Π3/2]c5d;Ωg (Ω = 0,2) Rydberg states of the I2–Kr van der Waals complex. Anharmonic progressions in the I2···Kr van der Waals stretching mode have been observed with e values of 49 ± 2 and 47 ± 2 cm−1 for the [2Π3/2]c5d;Ω = 0g and [2Π3/2]c5d;Ω = 2g states, respectively. The [2Π3/2]c5d;Ω = 2g state of I2–Kr has been used as an intermediate in a two-colour (2 + 1′) zero kinetic energy pulsed-field ionisation (ZEKE–PFI) photoelectron study of the 2Π3/2,g state of the I2+–Kr ionic complex. The adiabatic ionisation energy was determined to be 74248 ± 3 cm−1. An anharmonic vibrational progression in the I2+···Kr van der Waals stretching mode was observed giving a value of e = 55 ± 2 cm−1 for the 2Π3/2,g state of the complex. The [2Π1/2]c6s;Ω = 1g Rydberg state of the I2–N2 van der Waals complex has also been observed using REMPI spectroscopy. Anharmonic progressions in the I2···N2 van der Waals stretching mode have been observed with e = 71 ± 2 cm−1. Comparisons are made between the spectroscopic data obtained for the Rydberg states of I2–Kr and I2–N2 with the analogous Rydberg states in I2–Ar.