qceims

QCEIMS and movies from QCEIMS trajectories

Quantum Chemistry Electron Ionization Mass Spectrometry (QCEIMS) is a program for the prediction of mass spectra from first principles. It is based on a combination of Molecular Dynamics and elements of statistical theory, shown schematically below:"

To obtain the qceims executables and the related tools and scripts, please contact qceims@thch.uni-bonn.de

QCEIMS manual¹

For the original publication of the theory see:
S. Grimme, Towards First Principles Calculation of Electron Impact Mass Spectra of Molecules, Angew. Chem. Int. Ed., (2013), 52, 6306-6312.²

For a showcase of the prediction of the EI mass spectra of five organic drug molecules, see:
C. A. Bauer, S. Grimme, First principles calculation of electron ionization mass spectra for selected organic drug molecules, Org. Biomol. Chem., (2014), 12, 8737-8744.³

For QCEIMS studies of the fragmentation reactions of the nucleobases, see:
C. A. Bauer, S. Grimme, Elucidation of Electron Ionization Induced Fragmentations of Adenine by Semiempirical and Density Functional Molecular Dynamics, J. Phys. Chem. A, (2014), 118, 11479-11484a.⁴
C. A. Bauer, S. Grimme, Automated quantum chemistry based molecular dynamics simulations of electron ionization induced fragmentations of the nucleobases uracil, thymine, cytosine, and guanine, Eur. J. Mass Spectrom. (2015), 21, 125-140.⁵

For an overview over the QCEIMS program, a survey of the literature, and a small benchmark, see:
C. A. Bauer, S. Grimme, How to Compute Electron Ionization Mass Spectra from First Principles, J. Phys. Chem. A, (2016), 120, 3755-3766.⁶

For the implementation of a negative ion mode in QCEIMS and a simulation of negatively charged nitrile molecules, see:
V. Ásgeirsson, C. A. Bauer, S. Grimme, Unimolecular decomposition pathways of negatively charged nitriles by ab initio molecular dynamics, Phys. Chem. Chem. Phys., (2016), 18, 31017-31026.⁷

For the implementation of the GFN-xTB Hamiltonian into QCEIMS and the prediction of EI mass spectra across the periodic table, see:
V. Ásgeirsson, C. A. Bauer, S. Grimme, Quantum Chemical Calculation of Electron Ionization Mass Spectra for General Organic and Inorganic Molecules, Chem. Sci., (2017), 8, 4879-4895. ⁸

Recent publication:

J. Koopman, S. Grimme, Calculation of Electron Ionization Mass Spectra with Semiempirical GFNn-xTB Methods, ACS Omega (2019), 4, 15120-15133. DOI: 10.1021/acsomega.9b02011⁹

Movies (under construction)

5dodecanone_alpha¹⁰
c2h2_loss_in_indole ¹¹
c2h3_loss_triple_diss_in_octane¹²
c5h5_from_phenol ¹³
ethyl_from_pentyl_from_octane_with_h-shift.mpg¹⁴
h-transfer_in_butylbenzene_1 ¹⁵
h-transfer_in_butylbenzene_2 ¹⁶
h-transfer_in_butylbenzene_3 ¹⁷
h2_loss_in_octane ¹⁸
h2_loss_in_octane_2 ¹⁹
mclafferty_alternative_in_ethylacetate ²⁰
mclafferty_in_2pentanone ²¹
mclafferty_in_butanal ²²
mclafferty_in_ethylacetate²³
triple_diss_in_ethylacetate ²⁴
adenine-mz28²⁵
adenine-mz54²⁶
adenine-mz81²⁷
adenine-mz108²⁸
keto-c-mz69²⁹
rda-uracil³⁰
mc_L-2-hexanone³¹
phenol-65³²
phenol-66³³
taxol_annotated³⁴
tropylium³⁵
methanesulfonamide³⁶

QCEIMS and movies from QCEIMS trajectories

Movies (under construction)

Links