scholarly journals Analytic gradients for multiconfiguration pair-density functional theory with density fitting: Development and application to geometry optimization in the ground and excited states

2021 ◽  
Vol 154 (7) ◽  
pp. 074108
Author(s):  
Thais R. Scott ◽  
Meagan S. Oakley ◽  
Matthew R. Hermes ◽  
Andrew M. Sand ◽  
Roland Lindh ◽  
...  
2017 ◽  
Vol 19 (44) ◽  
pp. 30089-30096 ◽  
Author(s):  
Jie J. Bao ◽  
Laura Gagliardi ◽  
Donald G. Truhlar

MC-PDFT is more accurate than CR-EOM-CCSD(T) or TDDFT when averaged over the first four adiabatic excitation energies of CN.


Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 1947
Author(s):  
Delano P. Chong

After geometry optimization, the electron spectra of indole and four azaindoles are calculated by density functional theory. Available experimental photoemission and excitation data for indole and 7-azaindole are used to compare with the theoretical values. The results for the other azaindoles are presented as predictions to help the interpretation of experimental spectra when they become available.


Author(s):  
Riddhish Pandharkar ◽  
Matthew R. Hermes ◽  
Christopher J. Cramer ◽  
Donald G. Truhlar ◽  
Laura Gagliardi

RSC Advances ◽  
2021 ◽  
Author(s):  
Guanzhao Wen ◽  
Xianshao Zou ◽  
Rong Hu ◽  
Jun Peng ◽  
Zhifeng Chen ◽  
...  

Ground- and excited-states properties of N2200 have been studied by steady-state and time-resolved spectroscopies as well as time-dependent density functional theory calculations.


2013 ◽  
Vol 91 (9) ◽  
pp. 872-878 ◽  
Author(s):  
Stanislav R. Stoyanov ◽  
Cindy-Xing Yin ◽  
Murray R. Gray ◽  
Jeffrey M. Stryker ◽  
Sergey Gusarov ◽  
...  

The vanadium and nickel components in heavy oils and bitumen are important impurities in catalytic processing and form aggregates with other asphaltene components. Metalloporphyrins are commonly analyzed using the characteristic Soret band in the UV–vis absorption spectrum. However, the Soret band of metalloporphyrins in petroleum is broadened and weaker than expected based on the concentration of Ni and V in heavy oils and the extinction coefficients of isolated porphyrins. We hypothesize that the low intensity and broadening of the Soret band could be due to axial coordination of the metal center or fusion (annelation) of aromatic rings on the porphyrin π-system. This hypothesis is examined using the density functional theory for geometry optimization and time-dependent density functional theory (TD-DFT) for calculation of excited states of nickel(II) and vanadyl porphyrins with axially coordinated ligands and annelated polyaromatic hydrocarbons. Predictions of the excited electronic states performed using the tandem of TD-DFT and conductor-like polarizable continuum model of solvation support this hypothesis and provide insight into the extent of Soret band broadening and intensity decrease due to coordination and annelation. These computational results, validated with respect to visible absorption spectra, are important for understanding asphaltene aggregation and spectroscopic characterization and suggest methods for removal of transition metals from heavy oil.


2014 ◽  
Vol 16 (28) ◽  
pp. 14455-14462 ◽  
Author(s):  
Edward A. Briggs ◽  
Nicholas A. Besley

Different dispersion correction parameters are required to describe the interaction when the molecule is in an excited Rydberg state.


ChemPhysChem ◽  
2014 ◽  
Vol 15 (18) ◽  
pp. 3892-3892
Author(s):  
Csaba Daday ◽  
Carolin König ◽  
Johannes Neugebauer ◽  
Claudia Filippi

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