Calculated photoelectron spectra of isotopomers of the propargyl radical (H2C3H): An explicitly correlated coupled cluster study

Explicitly correlated coupled cluster theory at the (U)CCSD(T∗)-F12a level has been employed to study the vibrational structure of the first two bands of the low-temperature photoelectron spectra of four different isotopomers of the propargyl radical with C2v symmetry (H2C3H, H2C3D, D2C3H, and D2C3D). A five-dimensional anharmonic model is employed to calculate the peak positions and relative intensities. While the first band of the PE spectra of all four isotopomers is dominated by the adiabatic peak, the second band shows a progression in the pseudoantisymmetric CC stretching vibration v3 with relative intensities of 100:68:23:5:1 for n = 0-4 in the case of the most abundant isotopomer.