Beyond the Ground State: Predicting Electron Ionization Mass Spectra Using Excited-State Molecular Dynamics.

ABSTRACT: Here, we provide an algorithm that introduces excited states into the molecular dynamics prediction of the 70 eV electron ionization mass spectra. To decide the contributions of different electronic states, the ionization cross section associated with relevant molecular orbitals was calculated by the binary-encounter-Bethe (BEB) model. We used a fast orthogonalization model/single and double state configuration interaction (OM2/CISD) method to implement excited states calculations and combined this with the GFN1-xTB semiempirical model. Demonstrated by predicting the mass spectrum of urocanic acid, we showed better accuracies to experimental spectra using excited-state molecular dynamics than calculations that only used the ground-state occupation. For several histidine pathway intermediat

SUBMITTER: Wang S 

PROVIDER: S-EPMC11492808 | biostudies-literature | 2022 Sep

REPOSITORIES: biostudies-literature