Convergence of the density functional one-centre expansion for the molecular continuum: N 2 and (CH 3 ) 3 N

Abstract

A large-scale one-centre expansion with a radial B-spline basis set is implemented for bound and continuum states. A Kohn-Sham hamiltonian is employed with Hartree and exchange-correlation potentials calculated from the SCF electron density taken from a previous LCAO calculation. An inverse iteration method is used to obtain the continuum wavefunction, from which the cross section and asymmetry parameter are calculated. The convergence with respect to angular momentum and cut-o radius is analysed for N 2 . The relevance of multipolar contributions even at large distances is shown and suggestions for further improvements are given. In order to show that the present method is suitable to treat systems of moderate size, the (CH 3 ) 3 N molecule has also been calculated and the results are compared with experiment.

Full-dimensional theoretical description of vibrationally resolved valence-shell photoionization of H2O

“…We have evaluated the electronic continuum state ψαηlη by using the static-exchange density functional theory (DFT) 30,31 . This method has been shown to provide accurate photoionization cross sections for a large variety of molecules within the fixed nuclei approximation (see, e.g., Refs.…”

Vibrationally resolved photoelectron angular distributions from randomly oriented and fixed-in-space N2and CO molecules

“…[3,21], which is based on original work developed by Decleva and coworkers to treat molecular ionization at the molecule's equilibrium position [49][50][51][52]. Since the method has been described in detail in Refs.…”

The quantum chemistry of attosecond molecular science

“…For even larger molecules, the above methods are inapplicable due to the many electronic degrees of freedom. A successful methodology employed for a number of large molecules is the B‐spline static exchange density functional theory (DFT) method . In this approach, the CC expansion is reduced to a single term for each open ionization channel, that is, in Equation only the term with β = α is preserved in the sum over β and no short‐range functions are included.…”

“…A successful methodology employed for a number of large molecules is the B-spline static exchange density functional theory (DFT) method. 42,[95][96][97][98] In this approach, the CC expansion is reduced to a single term for each open ionization channel, that is, in Equation ( 9) only the term with β = α is preserved in the sum over β and no short-range functions Ξ N K are included. As a consequence, at variance with the methods described above, the static exchange DFT method cannot describe ionization accompanied by simultaneous excitation of a remaining electron, nor multiply excited states lying in the ionization continuum and the associated autoionizing decay.…”

“…For very large molecules, the all-B-spline static exchange DFT method 42,[95][96][97][98] is the only feasible alternative. As an illustration, Figure 7 shows a recent application of this method to describe the photoelectron spectrum of the tryptophan amino acid.…”