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, GENIUSH, Fortran
Selected articles
G. Czakó, T. Furtenbacher, A. G. Császár, and V. Szalay, Mol. Phys. 102, 2411 (2004).
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E. Mátyus, G. Czakó, B. T. Sutcliffe, and A. G. Császár, J. Chem. Phys. 127, 084102 (2007).
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E. Mátyus, G. Czakó, and A. G. Császár, J. Chem. Phys. 130, 134112 (2009).
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C. Fábri, E. Mátyus, A. G. Császár, J. Chem. Phys 134, 074105 (2011).
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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
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).
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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).
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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).
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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).
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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).
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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).
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Rotating full- and reduced-dimensional quantum chemical models of molecules
C. Fábri, E. Mátyus, and A. G. Császár, J. Chem. Phys. 134, 074105 (2011).
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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).
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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).
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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).
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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).
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Rovibrational resonances
Rotational-Vibrational Resonance States
A. G. Császár, I. Simkó, T. Szidarovszky, G. C. Groenenboom, T. Karman, and A. van der Avoird,
Phys. Chem. Chem. Phys. 22, 15081-15104 (2020).
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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).
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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).
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Rigidity of the Molecular Ion H5+
C. Fábri, J. Sarka, and A. G. Császár, J. Chem. Phys. 140, 051101 (2014).
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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).
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MARVEL: measured active rotational–vibrational energy levels. II. Algorithmic improvements
T. Furtenbacher and A. G. Császár, J. Quant. Spectr. Rad. Transfer 113, 929 (2012).
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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).
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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
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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).
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