135La

135La, or lanthanum-135, is a radionuclide of the lanthanum element (Z=57) with a mass number of 135. It is not found in appreciable quantities in nature; natural lanthanum is dominated by 139La, with trace amounts of other isotopes. 135La has been observed only in laboratory-produced samples, generated in high-energy nuclear reactions.

Production methods include projectile fragmentation and spallation of heavier nuclei at accelerator facilities, as well as fusion-evaporation reactions using enriched targets. As a proton-rich isotope, its existence and properties are studied in the context of the structure of mid-heavy, odd-A nuclei near Z=57.

135La is radioactive and short-lived. It decays by beta emission to nuclides in the vicinity of barium or cerium, depending on the decay path, often accompanied by gamma rays from excited-state de-excitation. The precise half-life and decay scheme have been determined in some experiments but remain subject to measurement and depend on the particular synthesis route and daughter states.

Its role in applications is predominantly in basic nuclear physics research, including studies of nuclear structure, decay schemes of proton-rich lanthanides, and benchmarking of theoretical models. No practical uses are associated with 135La due to its fleeting existence.

Further data can be found in nuclear data compilations such as the National Nuclear Data Center and the Chart of Nuclides.