GTOBAS is a program for fitting Gaussian-type orbitals (GTOs) to Bessel and Coulomb functions over a finite range. The exponents of the GTOs are optimized using the method of Nestmann and Peyerimhoff [J. Phys. B 23 (1990) L773]. The appended module NUMCBAS provides the numerical Bessel and Coulomb functions required as input for the program. The use of GTO continuum basis sets is particularly i...

In the development of spectroscopy the symmetric top molecule ammonia, NH 3 , has always played an important role f rom an experimental, theoretical and astrophysical point of view, and it continues to do so. It's pyramidal structure leads to the well known inversional transitions in the 1.2 cm wave region, which were the first molecular lines to be measured in absorption by microwave technique...

The presence of electric or microwave fields can modify the long-range forces between ultracold dipolar molecules in such a way as to engineer weakly-bound states molecule pairs. These so-called field-linked [Avdeenkov et al., Phys. Rev. Lett. 90, 043006 (2003), Lassabli\`ere 121, 163402 (2018)], which separation two bound be orders magnitude larger than themselves, have been observed resonance...

When Bose-Einstein condensed ~BEC! systems are coupled, dramatic phenomena occur, owing to macroscopic phase coherence. Effective second-quantized Hamiltonians are often used as simple models @1–3,5–7# to bring out the characteristic behavior of these systems. Very similar Hamiltonians are used @8–10# to model striking effects in vibrational spectra of polyatomic molecules, related to classical...

The electron stimulated desorption of D anions from deuterated hydrocarbons condensed on a platinum substrate has been studied experimentally. D anion yield functions are reported for incident electron energies ranging from 0 to 20 eV: For each molecule studied, the yield function exhibits a single dissociative attachment resonance at approximately 10 eV: Above 15 eV; a linearly increasing D io...

The photodynamics of bacteriorhodopsin were studied by transient absorption and gain measurements after excitation with femtosecond pulses at 620 nm. With probing pulses at longer wavelengths (A> 770 nm) the previously reported formation of the J intermediate (with a time constant of 500f 100 fs) was confirmed. With probing pulses around 700 nm, a faster process with a relaxation time of 200 rt...

Approximate semiclassical solutions are developed for a system of a Morse oscillator coupled to a harmonic oscillator via a nonlinear perturbation. This system serves as a model for the interaction of an excited stretching mode with a bending mode in a polyatomic molecule. Three semiclassical methods are used to treat this model. In particular, a matrix diagonalization, a two-state model, and a...

Abstract Calculations are performed for electron collision with the methylene molecular ion C mathvariant="normal">H 2 + </mml:m...

We introduce a new numerical grid-based method on unstructured grids in the three-dimensional real-space to investigate the electronic structure of polyatomic molecules. The Voronoi-cell finite difference (VFD) method realizes a discrete Laplacian operator based on Voronoi cells and their natural neighbors, featuring high adaptivity and simplicity. To resolve multicenter Coulomb singularity in ...