Rotation–vibration interactions in (HF)2. II. Rotation–vibration interactions in low-lying vibrational states

189

164

The interdependence of the description of the internal geometry and the corresponding kinetic energy operator T is investigated in detail for a general n-atomic molecule. For both space-fixed and body-fixed reference frames compact expressions of T are derived which are applicable to any set of nϪ1 translationally and rotationally invariant internal vectors in a spherical polar parametrization. Simple analytical forms are given for reduced masses and kinetic coupling constants, which are the only vector specific parameters in the final rovibrational kinetic energy expression. The kinetic energy assumes the most separable form for an entirely orthogonal set of internal vectors. A highly efficient computer program for the calculation of rovibrational spectra of tetratomic molecules has been developed on the basis of this formulation. Calculations on the HF dimer and the metastable molecule HOCO illustrate the accuracy and flexibility of this approach.

Section: B "Hf…supporting

confidence: 91%

Section: B "Hf…mentioning

confidence: 99%

Section: B "Hf…mentioning

confidence: 99%

See 1 more Smart Citation

Rovibrational Hamiltonians for general polyatomic molecules in spherical polar parametrization. I. Orthogonal representations

Mladenović

2000

189

164

“…First, by being able to calculate observable properties from first principles, one can improve his or her understanding of the underlying physics behind the observed phenomena. [3][4][5] In addition, by noting discrepancies between experiment and theory, one can modify potential energy surfaces in order to improve this agreement. [6][7][8][9][10] Over the past several decades, advances in theoretical approaches [11][12][13][14][15][16] and computational resources have made it possible to calculate the vibrational spectrum of a variety of strongly bound tri-and tetra-atomic molecules and clusters.…”

Section: Introductionmentioning

confidence: 99%

Rotation–vibration interactions in (HF)2. I. Using parallel supercomputers to calculate rotation–vibration energy levels

McCoy

Hayes

1999

Self Cite

Articles you may be interested inUsing fixed-node diffusion Monte Carlo to investigate the effects of rotation-vibration coupling in highly fluxional asymmetric top molecules: Application to H2D+ J. Chem. Phys. 138, 034105 (2013); 10.1063/1.4774318 On the variational computation of a large number of vibrational energy levels and wave functions for mediumsized molecules J. Chem. Phys. 131, 074106 (2009); 10.1063/1.3187528 Photodissociation of HOBr. I. Ab initio potential energy surfaces for the three lowest electronic states and calculation of rotational-vibrational energy levels and wave functionsAn algorithm for calculating rotation-vibrational energy levels and wave functions for AB-CD tetra-atomic systems is presented. By transforming the wave equation into a large sparse eigenvalue problem, we can take advantage of the implicitly restarted Lanczos method developed by Sorensen and co-workers. The algorithm has been applied to calculations of the lowest 40 bound states of (HF) 2 , (DF) 2 and HF•DF with even and odd parities. The lowest 40 energies and corresponding wave functions for (HF) 2 with Jϭ0 and even parity can be calculated in 10.5 minutes on 126 processors of a CRAY T3E. The resulting energy levels are found to be in excellent agreement with the previously reported values of Zhang, et al. ͓J. Chem. Phys. 102, 2315 ͑1995͔͒.

“…On the experimental side, much work has been done to determine its structure and tunneling dynamics, [9][10][11][12][13][14] vibrational predissociation lifetimes, [15][16][17][18][19][20] and rotational product state distributions. [21][22][23][24] On the theoretical side, the dimer has also been studied in a variety of ways, using quantum Monte Carlo methods, [25][26][27] four-dimensional rigid rotor 28 -31 and full six-dimensional ͑6D͒ bound state calculations, [32][33][34][35][36][37] as well as vibrational predissociation calculations. 33,[37][38][39] In the theoretical work, several potential energy surfaces ͑PESs͒ have been used, 25,[40][41][42] 43 which is based on explicitly correlated second-order Møller-Plesset calculations, and which is adjusted to reproduce the experimental dissociation energy and monomer stretch frequencies.…”

Section: Introductionmentioning

confidence: 99%

Spectrum and vibrational predissociation of the HF dimer. I. Bound and quasibound states

Vissers

Groenenboom

Avoird

2003

We present full six-dimensional calculations of the bound states of the HF dimer for total angular momentum Jϭ0,1 and of the quasibound states for Jϭ0 that correspond with vibrational excitation of one of the HF monomers, either the donor or the acceptor in the hydrogen bond. Transition frequencies and rotational constants were calculated for all four molecular symmetry blocks. A contracted discrete variable representation basis was used for the dimer and monomer stretch coordinates R,r A ,r B ; the generation of the monomer basis in the dimer potential leads to significantly better convergence of the energies. We employed two different potential energy surfaces: the SQSBDE potential of Quack and Suhm and the SO-3 potential of Klopper, Quack, and Suhm. The frequencies calculated with the SO-3 potential agree very well with experimental data and are significantly better than those from the SQSBDE potential.