Software Projects
Constrained Multi-Coordinate Driven Method
The program performs a reduced dimesnionality search with additional constraints on the weak predictors (Constrained Reduced Dimensionality method). The CRD method resembles the MCD method form Berente and Náray-Szabó [J. Phys. Chem. A 110 (2006) 772-778; doi: 10.1021/jp054116z], but the newly introduced constraints prevent the sudden changes in energy and geometry typical for driven methods. The CRD search is hadled with a C program while the necessary energy and force calculations are done with standard quantum chemical software (currently Gaussian 09) packages via an interface function. The analysis of the search and the generation of plots are managed with a set of shell scripts. The CRD methods performs best for chemical problems in which nearly degenerate conformers, such as a reacting solute surrounded by explicit solvent molecules, impede the localisation of the transition states or when alternative routes with similar or lower barriers misdirect the search for the reaction path of interest.
| languages: | C; perl and bash scripts |
| computer: | PC cluster with Linux (NTHU) |
| publications: | T. Lankau, C.-H. Yu; Phys. Chem. Chem. Phys. 16 (2014) 26658 - 26671; doi: 10.1039/C4CP03965C |
| S.-C. Yang, T. Lankau, C.-H. Yu; Green Chem. 16 (2014) 3999 - 4008; doi: 10.1039/C4GC01021C | |
| T. Lankau, C.-H. Yu; J. Chem. Phys. 138 (2013) 214102; doi: 10.1063/1.4807743 |
The Proton Movement in Idealized Hydrogen Bonds
This project consists of two parts. The first part is a C program to calculate the stationary wave function of a proton in a hydrogen bond which is described by a one-dimensional potential. The second part is a series of shell scripts and small C programs which connects the output of a Born-Oppenheimer molecular dynamics simulation (GAMESS US) with Gaussian 03 for the potential energy scans and the aforementioned C program to calculate the scpectroscopic properties of a thermally excited hydrogen bond.
| languages: | C; bash, tcsh and csh shell scripts |
| computer: | Apple iMac with OS X (office), PC cluster with Linux (NTHU / NCHC) |
| publications: | T. Lankau, C.-H. Yu; Phys. Chem. Chem. Phys. 13 (2011) 12758 - 12769; doi: 10.1039/c0cp02172e |
A Distributed Computing Algorithm for the Energy of Large Water Cluster
Stillinger's multi-center energy partition scheme [J. Chem. Phys. 53 (1970) 4544, doi: 10.1063/1.1673986] was applied to large water clusters and the individual quantum calculations for the smaller sub-cluster distributed over a heterogenous collection of UNIX based computers. The quantum calculations were done either with Gaussian 94, Gaussian 98 or GAMESS US while the calculation of the final energy and the distribution of the individual jobs (including basic load balancing) with my own code. The monetary driving force behind this program was to make various inexpensive computers form different sources work together on a single, large chemical problem.
| language: | C |
| computer: | IBM Power PC running on AIX |
| publications: | T. Lankau, A Computational Analysis of Hydrogen-Bonded Networks, Habilitation thesis, Hamburg 2005 |
| Download the habilitation thesis from my drop box. |
A Hückel-type Model for the 6s Molecular Orbitals in Platinum Clusters
The usability of a platinum cluster as a surface model depends on its electronic state and the population of the 6s molecular orbitals. To help the construction of the initial guess for the quantum calculations, a program was written to calculate the 6s molecular orbitals in these clusters using an extension of the Hückel model with an numerical approximation for the overlap integral.
| languages: | Pascal / C |
| computer: | Intel based PC |
| publications: | Nadja Tyzuk, Anwendung der Hückel Theorie in einem Cluster-Modell der Pt(111)-Oberfläche, Staatsexamen Thesis, Hamburg 2001 |
| T. Lankau, A Computational Analysis of the Platinum-Water-Vacuum Interface, PhD thesis, Hamburg 2000 | |
| Download the phd thesis from the server of the University Hamburg. |
Analysis of Mößbauer Spectra
The simulated annealing algorithm has been used to analyze the distribution of hyperfine paramaters in recorded Mößbauer spectra. The program has been successfully used to analyze the superparamagnetism of small particles in in silica supported iron oxide catalysts.
| language: | Object orientated version of Borland's Turbo Pascal for Windows |
| computer: | Intel based PCs with Windows 3.1 (to provide a graphical user interface) |
| publications: | T. Lankau, S. Bieber, K. Nagorny; Berichte der Bunsengesellschaft 102 (1998) 775 - 779; doi: 10.1002/bbpc.19981020511 |
| T. Lankau; 'Simulated Annealing' zur Auswertung von Mößbauerspektren mit verteilten Parametern; Diploma thesis, Hamburg 1994 | |
| notes: | The program has been used by other members of professor Nagorny's group for the analysis of their Mößbauer spectra. |
| A C++ version for IBM Power workstations (AIX) has been written later for pure number crunching. |