Our recent work on spectroscopy include

         Recursive Lanczos approach to eigenproblems.1-5

         Chebyshev propagation.6-11

         Filter diagonalization.12-17

         Symmetry adaptation in recursive eigensolvers.3,18-20

         Highly excited vibrational spectra of triatomic systems.21-29

         Highly excited vibrational spectra of tetratomic systems.30-33

         Resonances.17,34-38

         Density matrix propagators.39

References:

1.        Guo, H., Chen, R. & Xie, D. Calculation of transition amplitudes with a single Lanczos propagation. J. Theo. Comp. Chem. 1, 173 (2002).

2.        Chen, R. & Guo, H. A single Lanczos propagation method for calculating transition amplitudes. J. Chem. Phys. 111, 9944 (1999).

3.         Chen, R. & Guo, H. A single Lanczos propagation method for calculating transition amplitudes. II. modified QL and symmetry adaptation. J. Chem. Phys. 114, 1467 (2001).

4.         Li, S., Li, G. & Guo, H. A single Lanczos propagation method for calculating transition amplitudes. III. S-matrix elements with a complex-symmetric Hamiltonian. J. Chem. Phys. 115, 9637 (2001).

5.         Chen, R. & Guo, H. Effect of spectral range on convergence in Lanczos algorithm: a numerical approach. Chem. Phys. Lett. 369, 650 (2003).

6.         Chen, R. & Guo, H. The Chebyshev propagator for quantum systems. Comput. Phys. Comm. 119, 19 (1999).

7.         Chen, R. & Guo, H. Evolution of quantum system in order domain of Chebychev operator. J. Chem. Phys. 105, 3569 (1996).

8.         Guo, H. A time-independent theory of photodissociation based on polynomial propagation. J. Chem. Phys. 108, 2466 (1998).

9.         Chen, R. & Guo, H. Discrete energy representation and generalized propagation of physical systems. J. Chem. Phys. 108, 6068 (1998).

10.       Guo, H. An efficient method to calculate resonance Raman amplitudes via polynomial propagation. Chem. Phys. Lett. 289, 396 (1998).

11.       Chen, R. & Guo, H. On the convergence scaling laws of Lanczos and Chebyshev recursion methods. J. Chem. Phys. 119, 5762 (2003).

12.       Chen, R. & Guo, H. A general and efficient filter-diagonalization method without time propagation. J. Chem. Phys. 105, 1311 (1996).

13.      Chen, R. & Guo, H. Determination of eigenstates via Lanczos based forward substitution and filter-diagonalization. J. Comput. Phys. 136, 494 (1997).

14.       Chen, R. & Guo, H. Calculation of matrix elements in filter diagonalization: A generalized method based on Fourier transform. Chem. Phys. Lett. 279, 252 (1997).

15.       Chen, R. & Guo, H. A low-storage filter-diagonalization method to calculate expectation values of operators non-commutative to the Hamiltonian. vibrational assignement of HOCl. Chem. Phys. Lett. 308, 123 (1999).

16.      Chen, R. & Guo, H. Efficient calculation of matrix elements in low storage filter diagonalization. J. Chem. Phys. 111, 464 (1999).

17.       Xie, D., Chen, R. & Guo, H. Comparison of Chebyshev, Faber and Lanczos propagation based methods in calculating resonaces. J. Chem. Phys. 112, 5263 (2000).

18.       Chen, R. & Guo, H. Symmetry enhanced spectral analysis via spectral method and filter-diagonalization. Phys. Rev. E57, 7288 (1998).

19.       Chen, R., Guo, H., Liu, L. & Muckerman, J. T. Symmetry-adapted filter-diagonalization: Calculation of vibrational spectrum of planar acetylene from correlation functions. J. Chem. Phys. 109, 7128 (1998).

20.       Chen, R. & Guo, H. Extended symmetry-adapted discrete variable representation and accelarated calculation of HY. J. Chem. Phys. 110, 2771 (1999).

21.       Chen, R. & Guo, H. Benchmark calculations of bound states of HO2 via basic Lanczos algorithm. Chem. Phys. Lett. 277, 199 (1997).

22.       Ma, G., Chen, R. & Guo, H. Quantum calculations of highly excited vibrational spectrum of sulfur dioxide. I. Eigenenergies and assignments up to 15000 cm-1. J. Chem. Phys. 110, 8408 (1999).

23.       Ma, G. & Guo, H. Quantum calculations of highly excited vibrational spectrum of sulfur dioxide. II. Normal to local mode transition and quantum stochasticity. J. Chem. Phys. 111, 4032 (1999).

24.       Prosmiti, R., Farantos, S. C. & Guo, H. Assigning the transition from normal to local vibrational mode in SO2 by periodic orbits. Chem. Phys. Lett 311, 241 (1999).

25.       Xie, D., Ma, G. & Guo, H. Quantum calculations of highly excited vibrational spectrum of sulfur dioxide. III. Emission spectra from C state. J. Chem. Phys. 111, 7782 (1999).

26.       Parsons, B., Butler, L. J., Xie, D. & Guo, H. A combined experimental and theoretical study of resonance emission spectra of SO2(C1B2). Chem. Phys. Lett. 320, 499 (2000).

27.       Xie, D., Guo, H., Bludsky, O. & Nachtigall, P. Absorption and resonance emission spectra of SO2(X/C) calculated from ab initio potential energy and transition dipole moment surfaces. Chem. Phys. Lett. 329, 503 (2000).

28.       Li, G. & Guo, H. Accurate quantum calculation of vibrational level spectrum of H2O(X) up to dissociation limit. J. Mole. Spectrosc. 210, 90 (2001).

29.       Farantos, S. C., Lin, S. Y. & Guo, H. A regular isomerization path among chaotic vibrational states of CH2( a1A1). Chem. Phys. Lett. 399, 260 (2004).

30.       Chen, R., Ma, G. & Guo, H. Full-dimensional calculation of vibrational spectrum of hydrogen peroxide (HOOH). Chem. Phys. Lett. 320, 567 (2000).

31.       Chen, R., Ma, G. & Guo, H. Six-dimensional quantum calculation of highly excited vibrational energy levels of hydrogen peroxide and its deuterated isotopomers. J. Chem. Phys. 114, 4763 (2001).

32.       Xu, D., Chen, R. & Guo, H. Probing highly excited vibrational eigenfunctions using a modified single Lanczos method: Application to acetylene (HCCH). J. Chem. Phys. 118, 7273 (2003).

33.       Xu, D., Guo, H., Zou, S. & Bowman, J. M. A scaled ab initio potential energy surface for acetylene and vinylidene. Chem. Phys. Lett. (2003).

34.       Chen, R. & Guo, H. Extraction of resonances via wave packet propagation in Chebyshev order domain: collinear H+H2 scattering. Chem. Phys. Lett. 261, 605 (1996).

35.      Chen, R., Guo, H., Skokov, S. & Bowman, J. M. Theoretical studies of rotation induced Fermi resonances in HOCl. J. Chem. Phys. 111, 7290 (1999).

36.       Li, G. & Guo, H. Doubling of Chebyshev correlation function for calculating narrow resonances using low-storage filter diagonalization. Chem. Phys. Lett. 336, 143 (2001).

37.       Li, G. & Guo, H. Efficient calculation of resonance positions and widths using doubled Chebyshev autocorrelation functions. Chem. Phys. Lett. 347, 443 (2001).

38.       Lin, S. Y., Guo, H. & Farantos, S. C. Resonances of CH2(a1A1) and their roles in unimolecular and bimolecular reactions. J. Chem. Phys. 122, 124308 (2005).

39.       Guo, H. & Chen, R. Short-time Chebyshev propagator for the Liouville-von Neumann equation. J. Chem. Phys. 110, 6626 (1999).