arXiv subjects

Sukanya Jana

Publications and source records attributed to Sukanya Jana.

4 recordsLinked to original sources

arXiv2026

Geometrical Imperfections in a Digital Quadrupole Mass Filter: A Comprehensive Simulation Study in the First Stability Zone

Geometrical imperfections in quadrupole mass filters introduce higher-order field components that can significantly influence device performance, particularly under non-sinusoidal excitation. In this work, a comprehensive simulation study is carried out to investigate the effect of geometrical imperfections on the performance of a rectangular wave driven quadrupole mass filter operating in the first stability zone. Radial field distortions arising from controlled variations in rod geometry and position, including single rod radius variation, single rod displacement, diagonal rod radius variation, and diagonal rod displacement, are examined. These imperfections introduce octupole field components that distort the ideal quadrupolar field distribution. The influence of such distortions on key performance parameters, namely mass resolution and ion transmission efficiency, is systematically evaluated. The results show that the presence of radial asymmetry leads to a degradation of both resolution and transmission efficiency in all cases considered. Furthermore, the study reveals a strong dependence of mass filter performance on the initial state of the applied pulsed waveform, specifically whether the asymmetric rod pair is subjected to the high or low level of the RF pulse. These findings provide important insights into the tolerance limits of geometrical imperfections and their impact on the performance of pulsed wave driven quadrupole mass filters, which are relevant for the design and optimization of high-resolution digital mass filtering systems.

physics.chem-ph↗

arXiv2025

Signatures of emergent surface states across a displacive topological phase transition in Bi$_4$I$_4$

Topological phase transitions involving crystalline symmetry breaking provide a fertile ground to explore the interplay between symmetry, topology, and emergent quantum phenomena. Recently discovered quasi-one-dimensional topological material, Bi$_4$I$_4$, has been predicted to host topologically non-trivial gapless surfaces at high temperature, which undergo a finite temperature phase transition to a low temperature gapped phase. Here we present experimental signatures of this room temperature phase transition from a high-temperature $β$-phase with a surface state to a gapped $α$-phase hosting hinge states. Using real-space current mapping and resistance fluctuation spectroscopy, we identify signatures of a displacive topological phase transition mediated by a first-order thermodynamic structural change. Near the emergence of $β$-phase, we observe pronounced telegraphic noise, indicating fluctuating phase domains with topological surface states. The spatially resolved current map reveals electron transport via the gapless surface states in the $β$-phase, which vanishes upon transitioning to the $α$-phase with localized conduction channels (or hinge modes). Our experimental results, supported by first principles estimates and effective theory of a topological displacive phase transition, establish Bi$_4$I$_4$ as a candidate material showing intricate interplay of classical thermodynamic phase transitions with topological quantum phenomena.

cond-mat.str-el↗

arXiv2025

Radial asymmetry in quadrupole mass filters: stability, multipole fields and resolution enhancement

This study examines the effects of radial asymmetry in a linear quadrupole mass filter with circular rods, introduced either by a change in electrode radii or by displacement of a diametrically opposite pair. A radial potential model is developed to account for the resulting geometric deviations, enabling analysis of the first stability region specific to the quadrupole component. The transmission characteristics of such asymmetric configurations are systematically examined, revealing a linear shift in the transmission peak along the q-axis as a function of the asymmetry parameter. This behavior is interpreted through modifications observed in the stability diagram. Furthermore, increased asymmetry is shown to broaden the transmission contours and generally reduce resolution. Notably, a `magic' asymmetry parameter of -0.02 corresponding to electrode displacement, yields enhanced resolution compared to the symmetric case for a fixed rod-to-field radius ratio. An empirical relationship is established between the resolution and the combined contribution of the coefficients of octupole and dodecapole potential components, highlighting the critical role of higher-order field effects in performance optimization.

physics.chem-ph↗

arXiv2025

Effect of Rod Asymmetry on Field Distortions and Transmission Characteristics in Linear Quadrupole Mass Filters

This article reports the appearance of the octupole and hexadecapole components in the radial potential, which are otherwise absent in a linear quadrupole mass filter of symmetric round-rod configuration, if a small structural asymmetry is introduced in one electrode. Using the commercial ion simulation package SIMION, it is shown that the weightage of the octupole and hexadecapole potential increases with an increase in the asymmetry factor. A consistent correlation is observed between the octupole and dodecapole components, and between the hexadecapole and icosapole components with asymmetry added to different rod-to-field radius ratios. The transmission characteristics of the mass filter are studied for different asymmetry factors and rod-to-field radius ratios. The variation in the resolution parameter, as derived from the transmission contour, exhibits a strong correlation with the combined weightage of the multipole fields.

physics.chem-ph↗