Two-photon laser-optogalvanic spectroscopy of the odd-parity Rydberg series of krypton

We report new data on the odd-parity bound and autoionized Rydberg series of krypton using single-colour two-photon laser-optogalvanic spectroscopy. These series were excited from the and metastable levels. A total of 10 odd-parity , , , , , and unresolved (or ) Rydberg series are observed. The , , (or ) and Rydberg series have been observed up to n = 49, 44, 39 and 36 respectively. The interchannel interaction among the overlapping Rydberg series has been studied using the multichannel quantum-defect theory. In addition, the two-photon parity-forbidden Rydberg series excited from the level is also observed.