Angle-resolved photoemission spectroscopy from first-principles quantum Monte Carlo

Angle-resolved photoemission spectroscopy (ARPES) allows to visualize in momentum space the probability weight maps of electrons emitted from molecules deposited on a substrate¹. Within the plane wave approximation, these maps can be reproduced through the square modulus of the Fourier transform of the hole-quasi-particle wave function (hQPWFs), also known as Dyson orbital, associated to the electron that is photoemitted^2,3. The QPWFs naturally include all the correlation effects between the electrons involved in the process. On the other hand, the interpretation of these maps usually relies on the plane wave approximation, through the Fourier transform of single particle orbitals obtained from Density Functional Theory (DFT). Here we propose a many body approach based on quantum Monte Carlo (QMC) to directly calculate the hQPWFs of molecules in momentum space, reproducing ARPES data. Through the comparison between these correlated QMC images and their single particle counterparts, we visualize features that solely arise from many-body effects.

(1) P. Puschnig et al. Science (2009) 326, 702; (2) M. Dauth et al. New J. Phys. (2014) 16, 103005; (3) M. Barborini et al. J. Chem. Theory Comput. (2016), 12 (11), 5339-5349