Pujan Biswas

All Publications

• Experimental Measurement of the Rate Coefficient for OCS + M, with M = Ar, He, N2, CO2 in a Shock Tube Using Laser Absorption Spectroscopy. The journal of physical chemistry. A Panda, A., Biswas, P. A., Simitz, L. V., Streicher, J. W., Strand, C. L., Hanson, R. K. 2026

  Abstract

  A comprehensive understanding of sulfur chemistry is crucial for the characterization and modeling of planetary atmospheres. The unimolecular decomposition of carbonyl sulfide (OCS + M = CO + S + M) is a critical reaction for the development of accurate photochemical models. In this study, we employ laser absorption spectroscopy (LAS)-based diagnostics in a shock tube to investigate the rate coefficient of OCS decomposition. Sensitive and interference-free diagnostics were developed to monitor OCS depletion at 2070.858 cm-1 and CO formation at 2115.628 cm-1. The reaction rate coefficient of OCS decomposition was measured over a temperature range of 1800-2500 K. This work represents the first experimental determination of OCS decomposition rates in bath gases pertinent to several planetary environments (i.e., He, N2, and CO2). Additionally, we characterize the pressure dependence of the reaction rate through measurements at 1, 2, and 8 atm. The rate constant measured at 2 atm for argon, k1,Ar, aligns with previous studies and is given by k1,Ar = 3.48 × 10-10 exp (-257kJ/RT) cm3 molecule-1 s-1. The relative Chaperone efficiencies at 2 atm were determined as k1,He/k1,Ar = 2.68, k1,N2/k1,Ar = 1.85, and k1,CO2/k1,Ar = 3.67 through our experiments. Our results provide new insights into OCS kinetics, marking the first systematic study of its pressure-dependent behavior in exoplanetary-relevant conditions. These findings, underscored by low experimental uncertainties (±9.0% for k1,Ar, ±12% for k1,He, ±18% for k1,N2, and ±24% for k1,CO2) reflect high-quality, repeatable measurements that will support sulfur chemistry atmospheric modeling and enhance the interpretation of spectroscopic observations from missions such as the James Webb Space Telescope (JWST).

  View details for DOI 10.1021/acs.jpca.5c07383

  View details for PubMedID 41608828

• IR-HyChem: Towards modeling the high-T combustion behavior of aviation fuels using infrared spectra PROCEEDINGS OF THE COMBUSTION INSTITUTE Biswas, P., Boddapati, V., Klingberg, A. R., Panda, A., Wang, H., Hanson, R. K. 2025; 41

  View details for DOI 10.1016/j.proci.2025.105792

  View details for Web of Science ID 001546853400001

• LT-HyChem- A physics-based chemical kinetic modeling approach for low-temperature oxidation of real fuels I: Rationale, methodology, and application to a simple fuel mixture COMBUSTION AND FLAME Choudhary, R., Biswas, P., Boddapati, V., Wang, H., Hanson, R. K. 2025; 271

  View details for DOI 10.1016/j.combustflame.2024.113852

  View details for Web of Science ID 001396986200001

• New insights into the effect of molecular structure on stable intermediate formation during the pyrolysis of normal and branched alkanes - II: Impact of carbon number and degree of branching FUEL Boddapati, V., Biswas, P., Panda, A., Klingberg, A. R., Hanson, R. K. 2024; 373

  View details for DOI 10.1016/j.fuel.2024.132310

  View details for Web of Science ID 001260318500001

• New insights into the effect of molecular structure on stable intermediate formation during the pyrolysis of normal and branched alkanes - I: Multi-species time history measurements FUEL Boddapati, V., Biswas, P., Panda, A., Klingberg, A. R., Hanson, R. K. 2024; 373

  View details for DOI 10.1016/j.fuel.2024.132309

  View details for Web of Science ID 001260746500001

• Experimental and numerical investigation of shock wave-based methane pyrolysis for clean H₂ production SHOCK WAVES Ferris, A. M., Biswas, P., Choudhary, R., Hanson, R. K. 2024

  View details for DOI 10.1007/s00193-024-01159-4

  View details for Web of Science ID 001175260300001

• Understanding the impact of molecular structure on the formation of stable intermediates during the pyrolysis of monoalkylated cyclohexanes in a shock tube PROCEEDINGS OF THE COMBUSTION INSTITUTE Boddapati, V., Biswas, P., Panda, A., Klingberg, A. R., Hanson, R. K. 2024; 40 (1-4)

  View details for DOI 10.1016/j.proci.2024.105202

  View details for Web of Science ID 001253272200001

• Towards characterizing the effect of sustainable gasoline additives on the low-T reactivity of n-heptane using CO speciation in a shock tube PROCEEDINGS OF THE COMBUSTION INSTITUTE Biswas, P., Boddapati, V., Hanson, R. K. 2024; 40 (1-4)

  View details for DOI 10.1016/j.proci.2024.105484

  View details for Web of Science ID 001270258200001

• Multiwavelength Speciation in Pyrolysis of n-Pentane and Experimental Determination of the Rate Coefficient of nC5H12 = nC3H7 + C2H5 in a Shock Tube. The journal of physical chemistry. A Biswas, P., Choudhary, R., Hanson, R. K. 2023

  Abstract

  We report the application of a multiwavelength speciation strategy to the study of n-pentane (nC5H12) pyrolysis behind reflected shock waves in a shock tube. Experiments were conducted with 2% nC5H12/0.8%CO2/Ar (by mole) between 1150 and 1520 K in the pressure range of 1-2 atm. Utilization of laser absorption spectroscopy at eight wavelengths allowed time-resolved measurements of n-pentane, ethylene, methane, heavy alkenes, and temperature. The measured time histories were compared against the predictions of four recently developed chemical kinetic models for heavy hydrocarbons. It was found that none of the models reconciled the measured species time histories simultaneously. Sensitivity analysis was conducted to identify key reactions influencing the evolution of ethylene and other major pyrolysis products. The analysis revealed that the unimolecular decomposition of n-pentane into n-propyl and ethyl radicals has a dominating influence over the evolution of ethylene in the temperature range of 1150-1450 K. The rate coefficient of this reaction was then adjusted to match the measured ethylene time histories for each experiment. The rate coefficients thus determined, were fit against temperature using an Arrhenius expression given by k1(T) = 3.5 × 1014 exp(-67.2 kcal/RT) s-1. The average overall 2σ uncertainty of the measured rate coefficient was found to be ±35%, resulting primarily from uncertainties in the rate coefficients of secondary reactions. The measured rate coefficient, when used with the models, leads to a significant improvement in the prediction of species time histories. Further improvements in the model are possible if the rate coefficients of relevant reactions pertaining to small hydrocarbon chemistry are determined with an improved accuracy, and less uncertainty. To the best knowledge of the authors, this is the first experimental determination of the rate coefficient of C5H12 → nC3H7 + C2H5.

  View details for DOI 10.1021/acs.jpca.2c07538

  View details for PubMedID 36852653

• A laser-absorption sensor for in situ detection of biofuel blend vapor in engine intakes PROCEEDINGS OF THE COMBUSTION INSTITUTE Clees, S., Cha, D. H., Biswas, P., Boddapati, V., Cassady, S. J., Strand, C. L., Hanson, R. K., French, B., Gilmour, A., Hawk, K. C., Stitt, J. M., Ferlet, X. 2023; 39 (1): 1307-1316

  View details for DOI 10.1016/j.proci.2022.07.110

  View details for Web of Science ID 001019044900001

• A mid-IR laser absorption diagnostic for measuring formaldehyde at high pressures and its demonstration in shock tubes COMBUSTION AND FLAME Biswas, P., Choudhary, R., Panda, A., Davidson, D. F., Hanson, R. K. 2022; 245

  View details for DOI 10.1016/j.combustflame.2022.112366

  View details for Web of Science ID 000862966000011

• Thermometry and speciation for high-temperature and -pressure methane pyrolysis using shock tubes and dual-comb spectroscopy MEASUREMENT SCIENCE AND TECHNOLOGY Pinkowski, N. H., Biswas, P., Shao, J., Strand, C. L., Hanson, R. K. 2021; 32 (12)

  View details for DOI 10.1088/1361-6501/ac22ef

  View details for Web of Science ID 000702061800001