Special Issue Preface pubs.acs.org/JPCA
Introduction to the Special Issue on “ESDMC - 2013: Electronic Structure and Dynamics of Molecules and Cluster” he conference entitled “Electronic Structure and Dynamics on Molecules and Cluster (ESDMC - 2013)” held on February 17−20, 2013, at the Indian Association for the Cultivation of Science, Kolkata, India, highlighted theoretical developments in the following areas: (a) the beyond Born− Oppenheimer effect on photoabsorption spectra and reactive scattering processes; (b) molecule−surface scattering considering static surfaces and the surfaces at different temperatures; (c) electronic structure calculations to obtain accurate global (adiabatic) potential energy surfaces (PESs) and nonadiabatic coupling terms to construct diabatic PESs; (d) experiments in beyond Born−Oppenheimer situations and molecule−surface scattering processes. Both young and experienced scientists working on these funamentally important fields from all over world attended and presented their research work (http:// www.iacs.res.in/conferences/esdmc/files/Program_schedule. pdf) at this conference. This special issue in The Journal of Physical Chemistry A is a followup to the conference covering these diverse research activities. The issue is also enriched by contributions from several experimentalists. The Born−Oppenheimer (BO) approximation introduces a distinction between the fast electrons and slow moving nuclei in molecules. It has two important natural outcomes, viz. the adiabatic PESs and the nonadiabatic coupling terms (NACTs). The adiabatic PESs and the NACTs are the origin of the driving forces for governing the motion of the atoms in a molecular system. Even if a molecular process occurs in the ground state, the excited electronic states may affect the ground state dynamics very strongly due to the presence of the socalled “nonadiabatic coupling” terms and the BO approximate equation fails to calculate correct transition probabilities no matter how sophisticated a numerical algorithm is used for its solution. Several scattering calculations on one surface, two surfaces, and three surfaces have shown serious discrepancies between single-surface ordinary and multiple-surface “beyond” BO results. With the advancement of more precise product detection methods, experiments are being employed to measure rovibrationally state-to-state integral and differential cross-sections very accurately and theoretical attempts have been made to interpret such results on various tri/tetraatomic reactive systems. During the 1980s to 1990s many calculations of state-to-state scattering cross-sections were performed by solving the time-independent/dependent nuclear Schr̈odinger equation using Jacobi as well as hyperspherical coordinates. There are recent developments on time-dependent methodology using the hyperspherical coordinate system to calculate reactive cross-sections. Such contributions including recent experimental and theoretical developments in this area are presented in this special issue. During the last thirty years, molecule−surface scattering processes have been the focus of attention to understand the underlying mechanism at the microscopic level by both molecular beam experiments and first principle based
T
© 2013 American Chemical Society
theoretical approaches. Accurate experimental data are available for comparison with theoretically calculated data. Elastic and inelastic transition probabilities and chemisorption (sticking to the surface) and physisorption (weakly attached with the surface) of the diatom after colliding with low index metal surfaces are the observables. Quantum dynamics has been performed by several groups with a rigid surface, where the surface and surface−molecule interaction potential have been calculated by ab initio DFT calculation. Inclusion of two important effects appeared as a necessity to make the calculations realistic. One concerns the effect of surface modes and the other is electron hole pair that includes the effect of surface temperature. So far there are few attempts on both the aspects by employing first principle based treatment to compare the theoretical outcome with experimentally measured data. The conference had several talks on both experimental and theoretical progress to demonstrate the detailed advancement in this area, which is reflected in this special issue as well. Dynamical calculations on the Born−Oppenheimer and nonBorn−Oppenheimer PESs require an accurate global surface. For beyond Born−Oppenheimer dynamical processes, the calculation of nonadiabatic coupling terms is also a necessity. In the case of molecule−surface scattering dynamics, the molecule interacts with many surface atoms and the corresponding BO PES can be evaluated by employing approximate DFT methodologies. There were multiple talks on electronic structure theories and calculations for BO (adiabatic) surface, beyond BO (diabatic) surface, and molecule−surface interaction, where similar contributions came up in this special issue. The conference also had the purpose of celebrating the 65th birth anniversary of my former Ph.D. supervisor and colleague, Professor S. P. Bhattacharyya, Emeritus Professor, Department of Chemistry, IITB, India, who is an excellent scientist, a great teacher, and an extraordinary human being. Two consecutive sessions of this conference were dedicated to celebrate the occasion. Professor Bhattacharyya served our institute vis-à-vis the Department of Physical Chemistry for more than three decades. It would not be out of place to mention that the department has a rich tradition of high quality scientific research in the field of spectroscopy and theoretical chemistry. It was initiated by Professor Sadhan Basu in the mid-1950s and these areas were flourishing at the time of Professor Mihir Chowdhury and Professor Debashis Mukherjee.
Satrajit Adhikari, Guest Editor
■
Department of Physical Chemistry, Indian Association for the Cultivation of Science
AUTHOR INFORMATION
Corresponding Author
E-mail:
[email protected]. Special Issue: Structure and Dynamics: ESDMC, IACS-2013 Published: September 12, 2013 8495
dx.doi.org/10.1021/jp405524r | J. Phys. Chem. A 2013, 117, 8495−8496
The Journal of Physical Chemistry A
■
Special Issue Preface
ACKNOWLEDGMENTS While organizing this conference, I received overwhelming intellectual support through the participation by both the Indian and foreign scientists across the countries. The scientific organizations in India like DST, CSIR, BRNS, and my institute IACS helped us generously by providing the reasonable funding. Moreover, the technical help from the administration of IACS is gratefully acknowledged. Finally, I thank Professor George C. Schatz, Editor-in-Chief, and Professor Anne B. McCoy, Deputy Editor, for their kind support in the publication of this special issue.
8496
dx.doi.org/10.1021/jp405524r | J. Phys. Chem. A 2013, 117, 8495−8496
