INSTITUTE OF CHEMISTRY, EÖTVÖS UNIVERSITY

First-principles molecular spectroscopy


Description

Method development for the solution of the nuclear Schrödinger equation using variational and grid techniques.

Keywords

rotation-vibration motion, discrete variable representation, DOPI, DEWE, GENIUSH, Fortran

Selected articles

G. Czakó, T. Furtenbacher, A. G. Császár, and V. Szalay, Mol. Phys. 102, 2411 (2004). Read in PDF
E. Mátyus, G. Czakó, B. T. Sutcliffe, and A. G. Császár, J. Chem. Phys. 127, 084102 (2007). Read in PDF
E. Mátyus, G. Czakó, and A. G. Császár, J. Chem. Phys. 130, 134112 (2009). Read in PDF
C. Fábri, E. Mátyus, A. G. Császár, J. Chem. Phys 134, 074105 (2011). Read in PDF

Computation of quantum reaction rate coefficients


Description

Method development for the quantum chemical computation of reaction rates, state-to-state transition probabilities using …

Keywords

flux operator, reactive scattering, GENIUSH, Fortran

Spectroscopic networks


Description

Use of graph theory for the interpretation of high-resolution molecular spectra and linelists.

Keywords

graph theory, database management, MARVEL, C++

Selected articles

A. G. Császár and T. Furtenbacher, J. Mol. Spectrosc. 266, 99 (2011). Read in PDF

DEWE: Watson-operator-based polyatomic ro-vibrational program package


DEWE computes ro-vibrational energy levels and wave functions of polyatomic molecules. It is based on:
• Discrete variable representation (D)
• Eckart–Watson (EW) Hamiltonian expressed in rectilinear (normal) coordinates
• Exact (E) inclusion of the potential energy operator

Methodological details

Vibrational energy levels with arbitrary potentials using the Eckart–Watson Hamiltonians and the discrete variable representation
E. Mátyus, G. Czakó, and A. G. Császár, J. Chem. Phys. 127, 084102 (2007). Read in PDF
On variational computation of a large number of vibrational energy levels and wave functions for medium-sized molecules
E. Mátyus, J. Simunek, and A. G. Császár, J. Chem. Phys. 131, 074106 (2009). Read in PDF
Assigning quantum labels to variationally computed rotational-vibrational eigenstates of polyatomic molecules
E. Mátyus, C. Fábri, T. Szidarovszky, G. Czakó, W. D. Allen, and A. G. Császár, J. Chem. Phys. 133, 034113 (2010). Read in PDF

Applications

Capture of hydroxymethylene and its fast disappearance through tunnelling
P. R. Schreiner, H. P. Reisenauer, F. C. Pickard, A. C. Simmonett, W. D. Allen, E. Mátyus, and A. G. Császár, Nature 453, 906 (2008). Read in PDF
Variational quantum mechanical and active database approaches to the rotational-vibrational spectroscopy of ketene
C. Fábri, E. Mátyus, T. Furtenbacher, B. Mihály, T. Zoltáni, L. Nemes, and A. G. Császár, J. Chem. Phys. 135, 094307 (2011). Read in PDF

DOPI: triatomic ro-vibrational program package


DOPI computes ro-vibrational energy levels and wave functions of triatomic molecules. It is based on:
• Discrete variable representation (D)
• Sutcliffe–Tennyson Hamiltonian expressed in orthogonal (O) internal coordinates
• Direct-product basis (P)
• Iterative (I) eigensolver

Methodological details

Variational vibrational calculations using high-order anharmonic force fields
G. Czakó, T. Furtenbacher, A. G. Császár, and V. Szalay, Mol. Phys. 102, 2411 (2004). Read in PDF
The methylene saga continues: stretching fundamentals and zero-point energy of X 3B1 CH2
T. Furtenbacher, G. Czakó, B. T. Sutcliffe, A. G. Császár, and V. Szalay, J. Mol. Struct. 780-781, 283 (2006). Read in PDF
On the efficiency of treating singularities in triatomic variational vibrational computations. The vibrational states of H3+ up to dissociation
T. Szidarovszky, A. G. Császár, and G. Czakó, Phys. Chem. Chem. Phys. 12, 8373 (2010). Read in PDF

Applications

Accurate ab initio determination of spectroscopic and thermochemical properties of mono- and dichlorocarbenes
G. Tarczay, T. A. Miller, G. Czakó, and A. G. Császár, Phys. Chem. Chem. Phys. 7, 2881 (2005). Read in PDF
Bridging theory with experiment: a benchmark study of thermally averaged structural and effective spectroscopic parameters of the water molecule
G. Czakó, E. Mátyus, and A. G. Császár, J. Phys. Chem. A 113, 11665 (2009). Read in PDF

GENIUSH: general polyatomic quasi-variational ro-vibrational program package


GENIUSH computes ro-vibrational energy levels and wave functions for polyatomic molecules. The key features of GENIUSH are:
• General (GE), full- and reduced-dimensional DVR-based technique
• Numerically (N) constructed kinetic energy operator
• Internal (I) coordinates
• User specified Hamiltonian (USH)

Methodological details


Numerical kinetic energy operators in (quasi-)variational rovibrational computations
Toward black-box-type full- and reduced-dimensional variational (ro)vibrational computations
E. Mátyus, G. Czakó, and A. G. Császár, J. Chem. Phys. 130, 134112 (2009). Read in PDF
Rotating full- and reduced-dimensional quantum chemical models of molecules
C. Fábri, E. Mátyus, and A. G. Császár, J. Chem. Phys. 134, 074105 (2011). Read in PDF

Further developments made possible by GENIUSH
Modelling Non-Adiabatic Effects in H3+: Solution of the Rovibrational Schrödinger Equation with Motion-Dependent Masses and Mass Surfaces
E. Mátyus, T. Szidarovszky, and A. G. Császár, J. Chem. Phys. 141, 154111 (2014). Read in PDF
Numerically Constructed Internal-Coordinate Hamiltonian with Eckart Embedding and its Application for the Inversion Tunneling of Ammonia
C. Fábri, E. Mátyus, and A. G. Császár, Spectrochim. Acta A 119, 84 (2014). Read in PDF

Wavefunction analysis
Assigning Quantum Labels to Variationally Computed Rotational-Vibrational Eigenstates of Polyatomic Molecules
E. Mátyus, C. Fábri, T. Szidarovszky, G. Czakó, W. D. Allen, and A. G. Császár, J. Chem. Phys. 133, 034113 (2010). Read in PDF
The Role of Axis Embedding on Rigid Rotor Decomposition (RRD) Analysis of Variational Rovibrational Wave Functions
T. Szidarovszky, C. Fábri, and A. G. Császár, J. Chem. Phys. 136, 174112 (2012). Read in PDF


Applications

Temperature-dependent, effective structures of the 14NH3 and 14ND3 molecules
I. Szabó, C. Fábri, G. Czakó, E. Mátyus, and A. G. Császár, J. Phys. Chem. A 116, 4356 (2012). Read in PDF
Reduced-Dimensional Quantum Computations for the Rotational-Vibrational Dynamics of F--CH4 and F--CH2D2
C. Fábri, A. G. Császár, and G. Czakó, J. Phys. Chem. A 117, 6975-6983 (2013). Read in PDF
Rigidity of the Molecular Ion H5+
C. Fábri, J. Sarka, and A. G. Császár, J. Chem. Phys. 140, 051101 (2014). Read in PDF

MARVEL: Measured Active Vibrational Rotational Energy Levels


MARVEL computes ro-vibrational energy levels and their uncertainties from uniquely assigned measured transitions. The key steps of the MARVEL procedure are:
• Collection and critical evaluation of the measured, assigned transitions and their uncertainties
• Determination of tcomponents of the spectroscopic network (SN)
• Inversion of the transitions through a weighted least-squares-type procedure

Methodological details

MARVEL: measured active rotational–vibrational energy levels
T. Furtenbacher, A. G. Császár, and J. Tennyson, J. Mol. Spectry. 245, 115 (2007). Read in PDF
MARVEL: measured active rotational–vibrational energy levels. II. Algorithmic improvements
T. Furtenbacher and A. G. Császár, J. Quant. Spectr. Rad. Transfer 113, 929 (2012). Read in PDF

Applications

On employing H216O, H217O, H218O, and D216O lines as frequency standards in the 15-170 cm-1 window
T. Furtenbacher and A. G. Császár, J. Quant. Spectrosc. Rad. Transfer 109, 1234 (2008). Read in PDF
IUPAC Critical Evaluation of the Rotational-Vibrational Spectra of Water Vapor. Part I. Energy Levels and Transition Wavenumbers for H217O and H218O
J. Tennyson, P. F. Bernath, L. R. Brown, A. Campargue, M. R. Carleer, A. G. Császár, R. R. Gamache, J. T. Hodges, A. Jenouvrier, O. V. Naumenko, O. L. Polyansky, L. S. Rothman, R. A. Toth, A. C. Vandaele, N. F. Zobov, L. Daumont, A. Z. Fazliev, T. Furtenbacher, I. F. Gordon, S. N. Mikhailenko, and S. V. Shirin, J. Quant. Spectr. Rad. Transfer 2009, 110, 573-596 Read in PDF
IUPAC critical evaluation of the rotational-vibrational spectra of water vapor. Part II. Energy levels and transition wavenumbers for HD16O, HD17O, and HD18O
J. Tennyson, P. F. Bernath, L. R. Brown, A. Campargue, A. G. Császár, L. Daumont, R. R. Gamache, J. T. Hodges, O. V. Naumenko, O. L. Polyansky, L. S. Rothman, R. A. Toth, A. C. Vandaele, N. F. Zobov, S. Fally, A. Z. Fazliev, T. Furtenbacher, I. F. Gordon, S.-M. Hu, S. N. Mikhailenko, and B. Voronin, J. Quant. Spectr. Rad. Transfer 111, 2160 (2010). Read in PDF