Mixed ramp-Gaussian basis sets
A new, fast paradigm for describing core electrons
In 2014, I co-proposed a fundamentally new type of basis set, mixed ramp-Gaussian basis sets, that have the potential to revolutionise our ability to computationally model core electrons. These basis sets retain Gaussians to describe the valence electron distribution, but use a new type of basis function, the ramp which has an electron-nuclear cusp, to describe the core electron distribution.
These basis sets show promise in describing the core electrons effectively while still having fast integral calculations .
The Ramp function
RampItUp Program: An initial implementation
The RampItUp program implements a mixed ramp-Gaussian integral package, specifically for calculations with the R-31G and R-31+G basis set. This is a preliminary version of the code; any bugs or difficulties compiling should be reported directly to the author at laura.mckemmish@gmail.com.
RampItUp is available from GitHub at https://github.com/lauramckemmish/RampItUp
This program can be compiled with gfortran by running: bash compile.sh
A sample input is MyTest.sh that works also with a running qchem installation. If you don't have qchem installed, please comment out the 'qchem' commands.
A selection of molecule inputs and basis sets is given in the Data subfolder.
Please let me know if you have trouble compiling or running this code and I will do my best to help you.
Please cite the following paper if you publish work using this code:
LK McKemmish, JCP, 142, 134104 (2015)
Available projects
Elucidating the structural-spectral relation for complex NMR spectra of peptides using computational chemistry with specialised and novel basis sets (collaborations).
Keywords: Computational Chemistry, Link with Experiment, Basis Set Design, NMR spectroscopy
For more details, check out:
Accurate Electron Densities at Nuclei Using Small Ramp-Gaussian Basis Sets
LK McKemmish, ATB Gilbert, J. Chem. Theory Comput. 142 (13), 134104
Using 1H and 13C NMR chemical shifts to determine cyclic peptide conformations: a combined molecular dynamics and quantum mechanics approach
QNN Nguyen, J Schwochert, DJ Tantillo, RS Lokey, Phys.Chem.Chem.Phys., 2018, 20, 14003
