## Files in this item

FilesDescriptionFormat

application/pdf

587567.pdf (724kB)
PresentationPDF

application/pdf

1601.pdf (59kB)
AbstractPDF

## Description

 Title: Fit point-wise ab initio calculation potential energies to a multi-dimension morse/long-range model Author(s): Zhai, Yu Contributor(s): Le Roy, Robert J.; Li, Hui Subject(s): Spectroscopy of Large Amplitude Motions Abstract: \begin{wrapfigure}{r}{0pt} \includegraphics[scale=0.35]{mdmlr.eps} \end{wrapfigure} A potential energy surface (PES) is a fundamental tool and source of understanding for theoretical spectroscopy and for dynamical simulations. Making correct assignments for high-resolution rovibrational spectra of floppy polyatomic and van der Waals molecules often relies heavily on predictions generated from a high quality {\it ab initio} potential energy surface. Moreover, having an effective analytic model to represent such surfaces can be as important as the {\it ab initio} results themselves. For the one-dimensional potentials of diatomic molecules, the most successful such model to date is arguably the Morse/Long-Range'' (MLR) function developed by R.~J. Le~Roy and coworkers.\footnote{{\it Mol. Phys.} {\bf 105}, 663 (2007){\it J. Chem. Phys.} {\bf 131}, 204309 (2009){\it Mol.\ Phys.}\ {\bf 109}, 435 (2011).} It is very flexible, is everywhere differentiable to all orders. It incorporates correct predicted long-range behaviour, extrapolates sensibly at both large and small distances, and two of its defining parameters are always the physically meaningful well depth ${D}_e$ and equilibrium distance $r_e$. Extensions of this model, called the Multi-Dimension Morse/Long-Range (MD-MLR) function, %have been applied successfully to atom-plus-linear molecule systems\footnote{{\it Phys.\ Chem.\ Chem.\ Phys.}\ {\bf 10}, 4128 (2008){\it J.\ Chem.\ Phys.}\ {\bf 130}, 144305 (2009)}, linear molecule--linear molecule systems\footnote{{\it J. Chem. Phys.} {\bf 132}, 214309 (2010).} and atom--non-linear molecule\footnote{{\it J. Chem. Phys.} {\bf 140}, 214309 (2010).} system. have been applied successfully to atom-plus-linear molecule, linear molecule--linear molecule and atom--non-linear molecule systems.\footnote{{\it Phys.\ Chem.\ Chem.\ Phys.}\ {\bf 10}, 4128 (2008){\it J.\ Chem.\ Phys.}\ {\bf 130}, 144305 (2009){\it J. Chem. Phys.} {\bf 132}, 214309 (2010){\it J. Chem. Phys.} {\bf 140}, 214309 (2014){\it J. Chem. Phys.} {\bf 144}, 014301 (2016).} However, there are several technical challenges faced in modelling the interactions of general molecule-molecule systems, such as the absence of radial minima for some relative alignments, difficulties in fitting short-range potential energies, and challenges in determining relative-orientation dependent long-range coefficients. This talk will illustrate some of these challenges and describe our ongoing work in addressing them. Issue Date: 2016-06-20 Publisher: International Symposium on Molecular Spectroscopy Genre: Conference Paper / Presentation Type: Text Language: En URI: http://hdl.handle.net/2142/91111 Rights Information: Copyright 2016 by the authors Date Available in IDEALS: 2017-01-26
﻿