## Vladimir A. Mandelshtam

Professor, Chemistry

School of Physical Sciences

PH.D., Inst. of Spectroscopy, Acad. of Sciences of USSR, 1991

B.S., M.S., 1987, Moscow Institute of Steel and Alloys

Phone: (949) 824-5509

Fax: (949) 824-8571

Email: mandelsh@uci.edu

University of California, Irvine

2103 Natural Sciences II

Mail Code: 2025

Irvine, CA 92697

School of Physical Sciences

PH.D., Inst. of Spectroscopy, Acad. of Sciences of USSR, 1991

B.S., M.S., 1987, Moscow Institute of Steel and Alloys

Phone: (949) 824-5509

Fax: (949) 824-8571

Email: mandelsh@uci.edu

University of California, Irvine

2103 Natural Sciences II

Mail Code: 2025

Irvine, CA 92697

**Research Interests**

Theoretical and Computational Chemistry

**URL**

**Academic Distinctions**

Emerson Fellow, 1998

UCI Faculty Career Development Awards, 1999, 2001

Alfred P. Sloan Research Fellow, 2002-2004

UCI Faculty Career Development Awards, 1999, 2001

Alfred P. Sloan Research Fellow, 2002-2004

**Appointments**

1991-1997, University of Southern California

1997-1998, University of California, San Diego

1997-1998, University of California, San Diego

**Research Abstract**

Theoretical and computational methods provide a powerful tool for the study of chemical dynamics and often help us to understand the experiments. One area of our research is the development of such methods and their application to studying the dynamics of small molecules, radicals and clusters. If the quantum effects, such as tunneling or resonance phenomena, are essential, even the simplest chemical reactions involving only three atoms, e.g. H + O

_{2}--> OH + O, turn out to be very difficult to model numerically. This is because we cannot simply assume that the atoms move classically, i.e. according to Newton's equations of motion. In such cases we have to deal with the quantum equations for the wavefunctions (or wave packets), e.g. the time dependent SchrÃ¶dinger equation. Besides that, no matter whether they are classical or quantum the small molecules sometimes exhibit very complex behavior that we often call chaotic. Our goals are to develop numerical methods that can solve such problems most efficiently and to interpret the results of the numerical calculations. Our computational methods range from ab initio, which are designed to solve the quantum equations exactly, to those that try to employ certain approximations, such as semiclassical, simplifying the calculations while retaining the physically relevant properties of the system. There is no question about the role of computational methods in theoretical chemistry. They often allow us to look at the matter without actually conducting the experiment. However, their role in experimental chemistry is not always appreciated. A signal measured in an experiment has to be processed. Making certain assumptions about the data often helps us to reveal relevant physical information about the system in question. At this stage the efficiency of the experiment depends on how good our assumptions are and how sophisticated the computational methods we use for the signal processing are. Quite interestingly, the ideas of signal processing go back to Baron de Prony who more than 200 years ago believed that*all*physical processes could be described by a multi-exponential decay. This idea, somewhat modified and generalized, has recently found numerous applications in diverse areas, including chemistry. We are interested in several such applications, which range from quantum dynamics calculations to modern pulsed NMR experiments. Multidimensional NMR spectra are used for structure determination of large organic molecules. Enormous multidimensional data arrays are generated in such experiments and usually processed by conventional methods of spectral analysis based on the multidimensional Fourier transformation. In conjunction with A.J. Shaka we are applying to NMR data a new signal processing method, the*filter diagonalization method*(FDM) to replace the Fourier transform. This allows us to not only obtain higher resolved NMR spectra, but also to devise new experiments and produce new types of spectra that are more useful for structure determination.

Publications

**Thermodynamic Properties of Classical Lennard-Jones Clusters:**

**(a)**The size-temperature phase diagram for small Lennard-Jones clusters, P.A. Frantsuzov and V.A. Mandelshtam,

*Phys. Rev. E*

**2005**,

*72,*037102

(Link to article text)

**(b)**Structural transitions and melting in LJ

_{74-78}Lennard-Jones clusters from adaptive exchange Monte Carlo simulations, V.A. Mandelshtam, P.A. Frantsuzov and F. Calvo,

*J. Phys. Chem.*

**2006**,

*110,*5326.

(Link to article text)

**(c)**Multiple structural transformations in Lennard-Jones clusters: Generic versus size-specific behavior, V.A. Mandelshtam and P.A. Frantsuzov,

*J. Chem. Phys.*

**2006**,

*124,*20451

(Link to article text)

**(d)**Low-temperature structural transitions:

circumventing the broken-ergodicity problem, V.A. Sharapov, D. Meluzzi and V. A. Mandelshtam,

*Phys. Rev. Lett.*,

**2007**,

*98,*105701.

(Link to article text)

**(d)**Solid-Solid structural transformations in

Lennard-Jones clusters: Accurate simulations versus the Harmonic

Superposition Approximation, V.A. Sharapov and V. A. Mandelshtam,

*J. Phys. Chem.*,

**2007**,

*111,*10284.

(Link to article text)

**
**

**Quantum Statistical Mechanics**

**(a)**Gaussian resolutions for equilibrium density matrices, P.A. Frantsuzov, A. Neumaier and V.A. Mandelshtam,

*Chem. Phys. Lett.*

**2003**,

*381,*117-122.

(Link to article text

**(b)**Thermodynamics and equilibrium structure of Ne

_{38}cluster: Quantum Mechanics versus Classical, C. Predescu, P.A. Frantsuzov, A. Neumaier and .A. Mandelshtam,

*J. Chem. Phys.*

**2005**,

*122,*154305.

(Link to article text)

**(c)**Structural Transformations and Melting in Neon Clusters: Quantum Mechanics versus Classical Mechanics, P.A. Frantsuzov, D. Meluzzi and V.A. Mandelshtam,

*Phys. Rev Lett.*

**2006**,

*96,*113401.

(Link to article text)

**(d)**Equilibrium properties of quantum water clusters by the

Variational Gaussian Wavepacket Method, P.A. Frantsuzov and V.A. Mandelshtam,

*J. Chem. Phys.*

**2008**,

*128,*094304.

(Link to article text)

**(e)**Quantum transitions in Lennard-Jones clusters, J. Deckman, P.A. Frantsuzov and V.A. Mandelshtam,

*Phys. Rev. E*

**2008**,

*77,*052102.

(Link to article text)

**(e)**Quantum Disordering versus Melting in Lennard-Jones Clusters, J. Deckman and V.A. Mandelshtam,

*Phys. Rev. E.*

**2009**,

*79,*022101.

(Link to article text)

**(f)**Effects of quantum delocalization on structural changes of Lennard-Jones clusters, J. Deckman and V.A. Mandelshtam,

*J. Phys. Chem. A.*

**2009**,

*113,*7394.

(Link to article text)

**
**

**Resonance calculations using FDM:**

**(a)**Bound states and resonances of the hydroperoxyl radical HO

_{2}. An accurate quantum mechanical calculation using filter diagonalization, V.A. Mandelshtam, T.P. Grozdanov, and H.S. Taylor,

*J. Chem. Phys.*

**1995**,

*103,*10074-10084.

(Link to article text)

**(b)**The quantum resonance spectrum of the H

_{3}

^{+}molecular ion for J=0. An accurate calculation using filter diagonalization, V.A. Mandelshtam and H.S. Taylor,

*J. Chem. Soc., Faraday Trans.*

**1997**,

*93,*847-860.

(Link to article text)

**(c)**The unimolecular dissociation of the OH stretching states of HOCl: Comparison with experimental data, J. Weiss, J. Hauschildt, and R. Schinke, O. Haan, S. Skokov and J. M. Bowman, V. A. Mandelshtam, K. A. Peterson,

*J. Chem. Phys.*

**2001**,

*115,*8880-8887.

(Link to article text)

**
**

**Periodic orbit quantization:**

**(a)**High Resolution Quantum Recurrence Spectra: Beyond the Uncertainty Principle, J. Main, V.A. Mandelshtam and H.S. Taylor,

*Phys. Rev. Lett.*

**1997**,

*78,*4351-4354.

(Link to article text)

**(b)**Periodic orbit quantization by harmonic inversion, J. Main, V.A. Mandelshtam and H.S. Taylor,

*Phys. Rev. Lett.*

**1997**,

*79,*825-828.

(Link to article text)

**
**

**Using cross-correlation functions for semiclassical quantization:**

**(a)**Extraction of tunneling splittings from a real-time semiclassical propagation, V.A. Mandelshtam, M. Ovchinnikov,

*J. Chem. Phys.*

**1998**,

*108,*9206-9209.

(Link to article text)

**(b)**Semiclassical Spectra and Diagonal Matrix Elements by Harmonic Inversion of Cross-Correlated Periodic Orbit Sums, J.

Main, K. Weibert, V. A. Mandelshtam, and G. Wunner,

*Phys. Rev. E*

**1999**,

*60,*1639-1642.

(Link to article text)

**
**

**Superresolution methods for multidimensional spectral analysis:**

**(a)**The multidimensional filter diagonalization method. I. Theory and numerical implementation, V.A. Mandelshtam,

*J. Magn. Reson.*

**2000**,

*144,*343-356.

( Link to article text)

**(b)**The multidimensional filter diagonalization method. II. Applications to 2D, 3D and 4D NMR experiments, A.A. De Angelis, H. Hu, V.A. Mandelshtam, and A.J. Shaka,

*ibid.*357-366.

(Link to article text)

**(c)**RRT: The Regularized Resolvent Transform for high resolution spectral estimation, J. Chen, A.J. Shaka and V. A. Mandelshtam,

*J. Magn. Reson.*

**2000**,

*147,*129-137.

(Link to article text)

**(d)**The extended Fourier transform for 2D spectral estimation, G.S. Armstrong and V.A. Mandelshtam,

*J. Magn. Reson.*

**2001**,

*153,*22-31.

(Link to article text)

**(e)**A detailed review article:

FDM: the Filter Diagonalization Method for data processing in NMR experiments, V.A. Mandelshtam,

*Progress in NMR Spectroscopy*

**2001**,

*38,*159-196.

(Link to article text)

**(f)**Processing DOSY spectra using the regularized resolvent transform, G. S. Armstrong, N. M. Loening, J. E. Curtis, A. J. Shaka and V. A. Mandelshtam,

*J. Magn. Reson.*

**2003**,

*163,*139-148.

( Link to article text)

**(g)**Regularized resolvent transform for direct calculation of 45 degrees

projections of 2D J spectra, G. S. Armstrong, J. H. Chen, K. E. Cano, A. J. Shaka and V. A. Mandelshtam,

*J. Magn. Reson.*

**2003**,

*164,*136-144.

( Link to article text)

**(h)**Ultra-high resolution 3D NMR spectra from limited-size data sets, J. H. Chen, D. Nietlispach, A. J. Shaka and V. A. Mandelshtam,

*J. Magn. Reson.*

**2004**,

*169,*215-224.

( Link to article text)

**(i)**Rapid high-resolution 4-dimensional NMR spectroscopy using the filter diagonalization method and its advantages for detailed structural elucidation of oligosaccharides, G.S. Armstrong, V. A. Mandelshtam, A. J. Shaka and B. Bendiak,

*J. Magn. Reson.*

**2005**,

*173,*160-168.

( Link to article text)

**
**

**1D FDM for NMR:**

**(a)**Reference deconvolution, phase correction and line listing of NMR spectra by the 1D filter diagonalization method, H. Hu, Q.N. Van, V. A. Mandelshtam and A.J. Shaka,

*J. Magn. Reson.*

**2000**,

*134,*76-87.

(Link to article text)

**(b)**Multiscale filter diagonalization method for spectral analysis of noisy data with nonlocalized features, J. Chen and V.A. Mandelshtam,

*J. Chem. Phys.*

**2000**,

*112,*4429-4437.

(Link to article text)

**
**

**Efficient numerical methods for quantum scattering:**

**(a)**Pseudo-time Schrödinger equation with absorbing potential for quantum scattering calculations, A. Neumaier and V.A. Mandelshtam,

*Phys. Rev. Lett.*,

**2001**,

*86,*5031-5034.

(Link to article text)

**(b)**Further generalization and numerical implementation of pseudo-time Schrödinger equations for quantum scattering calculations, A. Neumaier and V.A. Mandelshtam,

*J. Theor. Comp. Chem.*,

**2002**,

*1,*0000

(Link to article text)

**(c)**A simple recursion polynomial expansion of the Green's function with absorbing boundary conditions. Application to the reactive scattering, V.A. Mandelshtam and H.S. Taylor,

*J. Chem. Phys.*

**1995**,

*103,*2903-2907.

(Link to article text)

**(d)**Harmonic inversion of time signals and its applications, V.A. Mandelshtam and H.S. Taylor,

*J. Chem. Phys.*

**1997**,

*107,*6756-6769.

(Link to article text)

**(e)**A low-storage filter diagonalization method for quantum eigenenergy calculation or for spectral analysis of time signals, V.A. Mandelshtam and H.S. Taylor,

*J. Chem. Phys.*

**1997**,

*106,*5085-5090.

(Link to article text)

**
**

**Inversion of time cross-correlation functions:**

**(a)**Harmonic inversion of time cross-correlation functions. The optimal way to perform quantum or semiclassical dynamics calculations, V.A. Mandelshtam,

*J. Chem. Phys.*

**1998**,

*108,*9999-10007.

(Link to article text)

**(b)**RRT: the Regularized Resolvent Transform for quantum dynamics calculations, V.A. Mandelshtam,

*J. Phys. Chem*,

**2001**,

*105,*2764-2769.

(Link to article text)

**(c)**On harmonic inversion of

cross-correlation functions by the filter diagonalization method, V.A. Mandelshtam,

*J. Theor. Comp. Chem.*,

**2003**,

*2,*1-9.

(Link to article text)

**Link to this profile**

**Last updated**

03/15/2010