Publications by authors named "Ritwik Mondal"

Electrochemistry of outer-sphere redox molecules involves an essentially intact primary coordination sphere with minimal secondary sphere adjustments, resulting in very fast electron transfer events even without a noble metal-based electrocatalyst. Departing from conventional electrocatalytic paradigms, we incorporate these minimal reaction coordinate adjustments of outer-sphere species to stimulate the electrocatalysis of energetically challenging inner-sphere substrates. Through this approach, we are able to show an intricate 8e and 9H transfer inner-sphere reductive electrocatalysis at almost half the energy input of a conventional inner-sphere electron donor.

View Article and Find Full Text PDF

The rising demand for portable energy conversion devices has spurred the advancement of direct liquid fuel cells (DLFCs) employing fuels such as alcohol, ammonia, hydrazine, and vitamin C. In these devices, various precious metal platforms have been explored to increase the de-electronation kinetics and reduce catalyst poisoning, but with substantial cost implications. We demonstrate the crucial role of ligands in non-precious organometallic complexes in influencing the de-electronation kinetics of fuel molecules through a unique substrate-ligand synergistic interaction.

View Article and Find Full Text PDF

Recent experimental confirmation of spin inertia in ferromagnets positions this well-developed material class as a prime candidate for THz frequency applications. Spin-torque driven critical spin dynamics, such as auto-oscillations, play the central role in many spin-based technologies. Yet, the pressing question on spin inertia's effect on spin-torque driven dynamics in ferromagnets has remained unexplored.

View Article and Find Full Text PDF

The extreme significance of heavy hydrogen (D) in medicinal, nuclear, and chemical sectors, despite its scarce natural abundance, underscores the vital imperative for inventing novel chemistries for its production. We showcase a spontaneous heavy hydrogen generator during commensurate electrical energy production by decoupling the direct chemistry of OD/D dual ions via a protium redox. This exergonic electrochemistry yields ∼357 mL of D in nearly 85 h of continuous operation, with a commensurate electrical energy output of 122 kJ/per mole of D.

View Article and Find Full Text PDF

Although the magnetic Gilbert damping was considered as a scalar quantity in micromagnetic and atomistic spin simulations, recent investigations show that the Gilbert damping parameter is a tensor. Here, we investigate the effect of anisotropic and chiral damping in one-sublattice ferromagnets and two-sublattice antiferromagnets. We employ linear response theory to calculate the susceptibility with the damping tensor and determine the ferromagnetic and antiferromagnetic resonance frequencies together with the effective damping.

View Article and Find Full Text PDF

To mitigate the mismatch between energy availability and energy demand due to day/night shifts and seasonal variations, intensive efforts have been dedicated to storing renewable energy in various energy storage modules. Redox flow batteries have an upper hand over conventional batteries as energy storage modules due to their capability of decoupling energy and power. However, interfacial events, such as mass transport and electron transfer, play pivotal roles in flow batteries' energy storage and conversion mechanisms.

View Article and Find Full Text PDF

The OH/H dual-ion gradient has a hidden electromotive force of 0.82 V under standard conditions; however, its non-redox nature completely prevents its direct interconversion as electrical driving force. We show by using organic molecules whose heterogeneous electron transfer is pH dependent, OH/H dual-ion energy can be directly harvested as electrical driving force for performing simultaneous electro-organic synthesis and hydrogen fuel production in an electricity effective manner.

View Article and Find Full Text PDF

Aqueous Zn-based batteries hold multiple advantages of eco-friendliness, easy accessibility, high safety, easy fabrication, and fast kinetics, while their widespread applications have been greatly limited by the relatively narrow thermodynamically stable potential windows (i. e., 1.

View Article and Find Full Text PDF

The magnetic inertial dynamics have previously been investigated for one sublattice ferromagnets. Here, we develop the magnetization dynamics in two-sublattice ferromagnets including the intra- and inter-sublattice inertial dynamics. First, we derive the magnetic susceptibility of such a ferromagnet.

View Article and Find Full Text PDF

A relativistic spin operator cannot be uniquely defined within relativistic quantum mechanics. Previously, different proper relativistic spin operators have been proposed, such as spin operators of the Foldy-Wouthuysen and Pryce type, that both commute with the free-particle Dirac Hamiltonian and represent constants of motion. Here we consider the dynamics of a relativistic electron spin in an external electromagnetic field.

View Article and Find Full Text PDF

The phenomenological Landau-Lifshitz-Gilbert (LLG) equation of motion remains as the cornerstone of contemporary magnetisation dynamics studies, wherein the Gilbert damping parameter has been attributed to first-order relativistic effects. To include magnetic inertial effects the LLG equation has previously been extended with a supplemental inertia term; the arising inertial dynamics has been related to second-order relativistic effects. Here we start from the relativistic Dirac equation and, performing a Foldy-Wouthuysen transformation, derive a generalised Pauli spin Hamiltonian that contains relativistic correction terms to any higher order.

View Article and Find Full Text PDF

Femtosecond magneto-optical pump-probe measurements of ultrafast demagnetization show an intriguing difference in the first 100 fs of the magneto-optical Kerr response depending on whether the polarization of the pump and probe beams are in parallel or perpendicular configuration (Bigot et al 2009 Nat. Phys. 5 515).

View Article and Find Full Text PDF

We present the first materials specific ab initio theory of the magnetization induced by circularly polarized laser light in metals. Our calculations are based on nonlinear density matrix theory and include the effect of absorption. We show that the induced magnetization, commonly referred to as inverse Faraday effect, is strongly materials and frequency dependent, and demonstrate the existence of both spin and orbital induced magnetizations which exhibit a surprisingly different behavior.

View Article and Find Full Text PDF

Background & Objectives: Insect wing morphology has been used in many studies to describe variations among species and populations using traditional morphometrics, and more recently geometric morphometrics. A landmark-based geometric morphometric analysis of the wings of three species of Aedes (Diptera: Culicidae), viz. Ae.

View Article and Find Full Text PDF

A PHP Error was encountered

Severity: Notice

Message: fwrite(): Write of 34 bytes failed with errno=28 No space left on device

Filename: drivers/Session_files_driver.php

Line Number: 272

Backtrace:

A PHP Error was encountered

Severity: Warning

Message: session_write_close(): Failed to write session data using user defined save handler. (session.save_path: /var/lib/php/sessions)

Filename: Unknown

Line Number: 0

Backtrace: