Complete basis set limit ionization potentials of O3 and NO2 using the multiconfigurational spin tensor electron propagator method (MCSTEP) Original Research Article

We have calculated low-lying principal vertical ionization potentials (IPs) of O3 and NO2 with the multiconfigurational spin tensor electron propagator method (MCSTEP) using several different basis sets. We obtain an estimate of complete basis set limit (CBS) MCSTEP IPs. This is the first time CBS estimates have been used with MCSTEP. We show that MCSTEP is accurate and reliable compared with experiment at the CBS limit for obtaining low-lying vertical IPs for open shell molecules such as NO2 and highly correlated molecules such as O3. Our results confirm previous assignments of photoelectron peaks based on calculations made using less accurate methods.