ISAJ Newsletter - Volume 9, Issue 2 (September 2024)

Upcoming Event: 15th ISAJ Annual Symposium

ISAJ will organize its 15th Annual Symposium on October 29 (Tuesday) 2024 in Embassy’s VCC Auditorium in Tokyo. This year’s theme is “Transformative Technologies for a Sustainable Future.”

Organized by Dr. Sahiba Bano (NIMS Namiki), Dr. Deeksha Arya (U. Tokyo) and Dr. Aaditya Manjanath (NIMS Sengen).

Call for Participation

• Submit your abstracts to make a presentation!
• Lend a hand in organizing; join the Organizing Committee!

Symposium Legacy

ISAJ has been organizing Annual Symposia since 2010. The primary objective is to promote interaction and exchange of ideas among Indian and Japanese scientists. Over the years, the symposium has achieved many other objectives:

• Platform to showcase excellent science by Indian researchers in Japan
• Opportunity for young Indian researchers to organize symposia
• Leadership development for the Indian research community

Symposia have been held in various locations including Embassy of India, University of Tokyo, AIST Tsukuba, Osaka University, online/hybrid mode, Tokai University, and Hokkaido University.

Be an organizer of ISAJ events! Join its executive committee!

Submit your proposals and ideas to [email protected] for organizational support.

From Editor’s Desk

Greetings and a warm welcome to the second issue of ISAJ Newsletter in 2024!

In this issue, we present you with one research article, an event report and a photo gallery, as well as about the upcoming 15th Annual Symposium. The Research Spotlight is on “An atomistic deep dive into chemical reactions” using an unconventional computational route to simulate reactions on supercomputers based on mathematical models.

The event report covers the visit of the director of CSIR Advanced Materials and Processes Research Institute (AMPRI), Bhopal, Dr. Avanish Kumar Srivastava, to National Research Institute for Materials Science in Tsukuba. The photo gallery features a short symposium for visiting high school students which ISAJ organized in collaboration with Japan Education Center and Information (JECI).

ISAJ has reached a milestone in organizing its annual symposia. It is going to organize its 15th Annual Symposium this month on the 29th October.

Research Spotlight: An Atomistic Deep Dive into Chemical Reactions

By Dr. Aaditya Manjanath, Research Center for Structural Materials, NIMS

Introduction

A chemical reaction is a process which involves a transformation of one set of substances (reactants) to another set (products), either initiated by an energy input (endothermic) or followed by an energy release (exothermic).

Two types of approaches are available when investigating reactions:

1. Experimental route: Substances combined using laboratory equipment
2. Computational route: Mathematical models based on fundamental principles simulated on supercomputers

The computational approach may be the only viable option for understanding ultrafast chemical reactions at sub-picosecond (10⁻¹² s) timescales, which may be difficult or unfeasible experimentally.

Ab Initio Molecular Dynamics (AIMD)

The simulation tool used to study chemical reactions is ab initio molecular dynamics (AIMD), wherein a feedback mechanism between electronic and nuclear degrees of freedom is embedded.

• Electronic degrees of freedom: Solving time-dependent Schrödinger equation for electrons
• Nuclear degrees of freedom: Treated as classical particles using Newton’s laws
• Wavefunction: Mathematical function containing entire system information

Limitations of Current Methods

The current state-of-the-art, time-dependent density functional theory molecular dynamics (TDDFT-MD), has been used extensively for excited-state dynamics. However, it depends on adiabatic local density approximation (ALDA), which:

• Is valid only for initial ground state
• Not valid for initially excited states
• Causes problems for endothermic processes like photochemical reactions

Novel TDGW-MD Method

In response to these issues, we developed non-adiabatic excited-state time-dependent GW molecular dynamics (TDGW-MD). This method:

• Fixes the band gap problem (underestimation of band gaps in semiconductors/insulators)
• Integrates GW accuracy into dynamics framework
• Ensures accurate energy estimation for chemical reaction dynamics

Workflow of TDGW-MD

1. Read structural information - System configuration and initial excited state
2. DFT calculation - Converge electronic state through self-consistent procedure
3. GW correction - Correct energy levels for accuracy
4. Solve TDSE - Using accurate GW information
5. Update coordinates - Using Newton’s laws for next time instant
6. Loop - Continue until defined MD steps reached

Methane Bond Dissociation Case Study

We employed TDGW-MD to study photolysis of methane (CH₄ → CH₃• + H•), important for hydrogen production in alternative energy applications.

Simulation Details:

• Started with electron excitation from HOMO to LUMO
• Time evolution tracked through charge density changes
• Dissociation observed at 34 femtoseconds

Results Comparison:

TDDFT-MD severely underestimates electron energies by 4-6 eV, while TDGW-MD results are in excellent agreement with experimental values.

Conclusion

TDGW-MD is necessary for accurate study of excited-state chemical reactions, particularly for:

• Ultrafast reactions at sub-picosecond timescales
• Photochemical processes
• Hydrogen production reactions
• Systems where conventional methods fail

Event Report: Visit of CSIR-AMPRI Director Dr. Avanish K. Srivastava

Renowned materials scientist Dr. Avanish Kumar Srivastava, Director of CSIR-Advanced Materials and Processes Research Institute (AMPRI), Bhopal, visited the National Institute for Materials Science (NIMS) at Tsukuba from July 4-5, 2024.

Welcome and Presentation

Dr. Srivastava was warmly greeted by Dr. Takahito Ohmura, Director of the Research Centre for Structural Materials (RCSM) at NIMS. He presented a steel idol of Lord Ganesha, 3D-printed at AMPRI, symbolizing the institute’s advanced manufacturing capabilities.

Scientific Talk

Dr. Srivastava delivered a talk entitled “New and Innovative Materials for a Range of Uses”, attended by scientists, researchers and students engaged in diverse materials research. Key highlights included:

• Recent research and technological breakthroughs from AMPRI
• Successful collaborations with industry and society
• CSIR-AMPRI success story in developing cutting-edge indigenous Raman spectrometers

Interactive Sessions

Research Discussion Session:

• Platform for Indian postdoctoral researchers at NIMS
• Discussion of collaborative and career opportunities with Indian institutions
• Exploration of ongoing projects and challenges at AMPRI

Personal Interactions:

• Met several scientists/group leaders at NIMS
• Discussed future collaboration opportunities
• Evening session for informal discussions

Embassy Reception

Dr. Srivastava was invited by Dr. Yashawant Dev Panwar, Counsellor (S&T), Embassy of India in Tokyo, to a reception on June 6, 2024. Attendees included:

• Deputy Chief of Indian Mission Mr. Madhu Sudan
• Officials from Japan Society for Promotion of Science (JSPS)
• Prominent scientists in Japan

Photo Gallery: ISAJ-JECI High School Symposium

ISAJ organized a short symposium for visiting high school students in collaboration with Japan Education Center and Information (JECI) at the Embassy of India auditorium on August 5, 2024.

Distinguished Speakers:

• H.E. Ambassador Mr. S. George
• Dr. S. Kaul (ISAJ Chair)
• Capt. R. Adhikari (President JECI)
• Dr. Y. Ohmiya
• Dr. A. Manjanath
• Dr. A. Singh
• Dr. R. Wadhwa
• Dr. Anubhav
• Dr. R. Garg

This outreach event engaged the next generation of scientists, fostering interest in India-Japan scientific collaboration among high school students.