Publications

2026

Spectroscopy and dynamics of the v = 1 levels derived from the OH(D) stretching modes in the I‾∙HDO complex using CW and time-resolved, resonant two-photon infrared excitation of the cryogenically cooled ions

Payten A. Harville, Thien Khuu, Nan Yang, Michael Rosen, Mark A. Boyer, Meng Huang, Anne B. McCoy, and Mark A. Johnson

Int. J. Mass Spectrom., Special issue dedicated to Albert A. Viggiano on the occasion of his retirement from federal service, Vol. 524, pp. 117620

DOI Link: 10.1016/j.ijms.2026.117620

Autobiography of Mark A. Johnson

Mark A. Johnson

The Journal of Physical Chemistry A, Vol. 130, (9), March 5, 2026pp. 1739-1745

DOI Link: https://doi.org/10.1021/acs.jpca.6c00659

Microcanonical Kinetics of Water-Mediated Proton Transfer in 4ABAH⁺‧(H₂O)_n=4-6 Clusters (ABA = Aminobenzoic Acid): A Model System for Size-Dependent Relaxation to Ergodic Behavior

Abhijit Rana, Payten A. Harville, Mark A. Johnson

Journal of the American Chemical Society, pp. N/A

DOI Link: 10.1021/jacs.6c02472

2025

Dynamics of Protonated Oxalate from Machine-Learned Simulations and Experiment: Infrared Signatures, Proton Transfer Dynamics and Tunneling Splittings

Valerii Andreichev, Silvan Kaser, Erica L. Bocanegra, Madeeha Salik, Mark A. Johnson and Markus Meuwly

Phys. Chem. Chem. Phys., Vol. 27, Oct. 21, 2025 pp. 23288-23300

DOI Link: 10.1039/D5CP03085D

Structural Insight into ESI+-Generated Ions of Oxazolochlorin Derivatives using Cryogenic Infrared Spectroscopy

Kim Greis, Franziska Dahlmann, Erica Bocanegra, Madeeha Salik, Fabian Menges, Mark Johnson, and Christian Brückner

J. Am. Soc. Mass Spectrom., Vol. 37, (1), December 15, 2025 pp. 289-300

DOI Link: 10.1021/jasms.5c00333

Microcanonical Kinetics of Water-Mediated, Long Range Proton Transfer in Microhydrated 4-Aminobenzoic Acid

Abhijit Rana, Payten A. Harville, Thien Khuu, and Mark A. Johnson*

Science, Vol. 389, (6765), Sep 11, 2025 pp. 1143-1146

DOI Link: 10.1126/science.ady1723

Cryogenic Ion Kinetics and Thermodynamics in a Temperature Controlled, Radiofrequency Ion Trap: A Case Study of the “Tag Isomers” Adopted by the Py-CH₂-COOH⁺·D₂ Cation

Payten A. Harville, Erica L. Bocanegra, Madeeha Salik, and Mark A. Johnson*

J. Phys. Chem. Lett., August 20, 2025pp. 8799-8805

DOI Link: 10.1021/acs.jpclett.5c02149

The onset for vibrationally-induced, intra-molecular proton transfer at three water molecules in microhydrated 4-aminobenzoic acid

Abhijit Rana, Payten A. Harville, Thien Khuu, R. Allen LaCour, Teresa Head-Gordon, and Mark A. Johnson

J. Phys. Chem. Lett., (16), 18pp. 5252-5257

DOI Link: https://doi.org/10.1021/acs.jpclett.5c00701

Mechanism of a Halogen Exchange Reaction in Water: Catalysis by Aqueous Media

Imon Mandal, Itai Zakai, Natalia Karimova, Mark Johnson, and R. Benny Gerber

ACS Central Science, Vol. 11, (4), April 2025pp. 520-527

DOI Link: https://doi.org/10.1021/acscentsci.4c02228

Isomers and band assignments in the cryogenic vibrational spectrum of the binary complex between water and protonated formic acid using two color, IR-IR photobleaching and H/D isotopic substitution

Erica L. Bocanegra, Abhijit Rana, Anne B. McCoy, Mark A. Johnson

J. Chem. Phys. special issue "David Jonas Festschrift", Vol. 162, pp. N/A

DOI Link: 10.1063/5.0269798

Characterization of two positional isomers of the Cs⁺Gly complex using two-color, IR-IR photobleaching of the cryogenically cooled ions

Erica L. Bocanegra, Madeeha Salik, Yarra Hassan, Abhijit Rana, Anne B. McCoy, P.B. Armentrout, Mark A. Johnson*

Journal of Physical Chemistry A. Special Issue "Michael A. Duncan Festschrift", Vol. 129, (51), December 10, 2025 pp. 11877-11883

DOI Link: 10.1021/acs.jpca.5c07323

2024

Intramolecular Polarization Contributions to the pK_a’s of Carboxylic Acids Through the Chain Length Dependence of Vibrational Tag-shifts in Cryogenically Cooled Pyridinium-(CH₂)_nCOOH (n = 1-7) Cations

Payten A. Harville, Olivia C. Moss, Yarra Hassan, Lasse Hunger, Ralf Ludwig, Anne B. McCoy*, and Mark A. Johnson*

J. Phys. Chem. A, special issue "Vicki H. Grassian Festschrift", Vol. 128, (47), pp. 10159-10166

DOI Link: 10.1021/acs.jpca.4c05241

Isomer-specific, Cryogenic Ion Vibrational Spectroscopy Investigation of D₂- and N₂- Tagged, Protonated Formic Acid Complexes Using Two Color, IR-IR Photobleaching

Erica L. Bocanegra, Abhijit Rana, Anne B. McCoy, Mark A. Johnson

J. Phys. Chem. Lett., Vol. 15, pp. 10944-10949

DOI Link: https://doi.org/10.1021/acs.jpclett.4c02685

Demonstration of Capture, Cooling, Tagging, and Spectroscopic Characterization of UV Photoproduct Ions in a Cryogenic Ion Trap: Application to 266 nm Photofragment Ions from Rhodamine 6G

Payten A. Harville, Olivia C. Moss, Abhijit Rana, Elizabeth A. Snowden, and Mark A. Johnson

J. Phys. Chem. A special issue "Richard J. Saykally Festschrift" , Vol. 128, (36), 12pp. 7714-7719

DOI Link: 10.1021/acs.jpca.4c04283

Measuring the Electric Fields of Ions Captured in Crown Ethers

Anwesha Maitra, William R. Lake, Ahmed Mohamed, Sean C. Edington, Pratyusha Das, Barry C. Thompson, Sharon Hammes-Schiffer, Mark Johnson, and Jahan M. Dawlaty

J. Phys. Chem. Lett., Vol. 15, (27), pp. 7458-7465

DOI Link: https://pubs.acs.org/doi/full/10.1021/acs.jpclett.4c01303

Spectroscopic evidence for doubly hydrogen-bonded cationic dimers in the solid, liquid and the gaseous phases of carboxyl-functionalized ionic liquids

Hunger, Lasse; Al Sheakh, Loai; Fritsch, Sebastian; Villinger, Alexander; Ludwig, Ralf; Harville, Payten; Moss, Olivia; Lachowicz, Anton; Johnson, Mark

J. Phys. Chem. B, Vol. 128, (22), 22pp. 5463-5471

DOI Link: https://doi.org/10.1021/acs.jpcb.4c02094

Hydrogen Tag Shifts as Vibrational Reporters for Positional Isomers of Formylphenides: Surprising Mobility of the Carbanion Center Upon Collisional Decarboxylation of the Parent Benzoates

Olivia C. Moss, Tim Schleif, Joseph P. Messinger, Anna G. Rullán Buxó, Kim Greis, Evan H. Perez, Mark A. Johnson

J. Phys. Chem. Lett., Vol. 15, (7), pp. 1969-1974

DOI Link: https://doi.org/10.1021/acs.jpclett.3c03514

2023

Characterization of the oxazolone and macrocyclic motifs in the b_n (n = 2-5) product ions from CID of protonated oligoglycine peptides with isomer-selective, cryogenic vibrational spectroscopy

Ahmed Mohamed, Abhijit Rana, Evan Perez, Franziska Dahlmann, Allison Fry, Fabian S. Menges, Michael van Stipdonk, Svenja Jaeger, Mark A. Boyer, Anne B. McCoy, Mark A. Johnson

JASMS, Vol. 35, (2), pp. 326-332

DOI Link: https://doi.org/10.1021/jasms.3c00372

Intra-cluster charge migration upon hydration of protonated formic acid revealed by anharmonic analysis of cold ion vibrational spectra

Thien Khuu, Tim Schleif, Ahmed Mohamed, Sayoni Mitra, Jesus Valdiviezo, Joseph P. Heindel, Teresa Head-Gordon, and Mark A. Johnson

J. Phys. Chem. A, Vol. 127, (36, Marsha Lester Festschrift), pp. 7501-7509

DOI Link: https://doi.org/10.1021/acs.jpca.3c03971

Characterization of Oxidation Products from HOCl Uptake by Microhydrated Methionine Anions using Cryogenic Ion Vibrational Spectroscopy

Santino J. Stropoli, Kim Greis, Tim Schleif, and Mark A. Johnson

J. Phys. Chem. A, Vol. 127, (19), pp. 4269–4276

DOI Link: https://doi.org/10.1021/acs.jpca.3c00509

Cover Articles

Autobiography of Mark A. Johnson

DOI Link: https://doi.org/10.1021/acs.jpca.6c00659

Mechanism of a Halogen Exchange Reaction in Water: Catalysis by Aqueous Media

DOI Link: https://doi.org/10.1021/acscentsci.4c02228

Hydrogen Tag Shifts as Vibrational Reporters for Positional Isomers of Formylphenides: Surprising Mobility of the Carbanion Center Upon Collisional Decarboxylation of the Parent Benzoates

DOI Link: https://doi.org/10.1021/acs.jpclett.3c03514

Effects of Microhydration on the Mechanisms of Hydrolysis and Cl^- Substitution in Reactions of N₂O₅ and Seawater

DOI Link: https://doi.org/10.1002/cphc.202200819

Water Network Shape-Dependence of Local Interactions with the Microhydrated –NO₂⁻ and –CO₂⁻ Anionic Head Groups by Cold Ion Vibrational Spectroscopy

DOI Link: 10.1021/acs.jpca.2c00721

Preparation and Characterization of the Halogen Bonding Motif in the Isolated Cl⁻∙IOH Complex with Cryogenic Ion Vibrational Spectroscopy

DOI Link: 10.1021/acs.jpclett.2c00218

Vibrational signatures of HNO₃ acidity when complexed with microhydrated alkali metal ions, M⁺∙(HNO₃)(H₂O)_n=5 (M=Li, K, Na, Rb, Cs), at 20 K

DOI Link: 10.1021/acs.jpca.1c10352

Size-Dependent Onset of Nitric Acid Dissociation in Cs⁺(HNO₃)(H₂O)_n=0-11 Clusters at 20 K

DOI Link: 10.1021/acs.jpclett.1c00235

Isolating the Contributions of Specific Network Sites to the Diffuse Vibrational Spectrum of Interfacial Water With Isotopomer-Selective Spectroscopy of Cold Clusters

DOI Link: 10.1021/acs.jpca.0c07795

Ionic Liquid Clusters Generated from Electrospray Thrusters: Cold Ion Spectroscopic Signatures of Size-Dependent Acid−Base Interactions

DOI Link: 10.1021/acs.jpca.0c07595

Vibrational Spectroscopy of the Cryogenically Cooled O- and N-Protomers of 4-Aminobenzoic Acid: Tag Effects, Isotopic Labels, and Identification of the E,Z Isomer of the O-Protomer

DOI Link: 10.1016/j.ijms.2020.116427

Spectroscopic Signatures of Mode-Dependent Tunnel Splitting in the Iodide-Water Binary Complex

DOI Link: 10.1021/acs.jpca.0c00853

Integration of High-Resolution Mass Spectrometry with Cryogenic Ion Vibrational Spectroscopy

DOI Link: 10.1007/s13361-019-02238-y

Tag-Free and Isotopomer-Selective Vibrational Spectroscopy of the Cryogenically Cooled H₉O₄⁺ Cation with Two-Color, IR-IR Double-Resonance: Isolating the Spectral Signature of a Single OH Group in the Hydronium Ion Core

DOI Link: 10.1021/acs.jpca.8b08507

Isolation of the site-specific anharmonicities of individual water molecules in the Iˉ∙(H₂O)₂ complex using tag‐free, isotopomer selective IR‐IR double resonance

DOI Link: 10.1016/j.cplett.2017.09.042

Spectroscopic characterization of a strongly interacting C₍₂₎H group on the EMIM⁺ cation in the (EMIM⁺)₂Xˉ, (X = BF₄, Cl, Br, and I) ternary building blocks of ionic liquids

DOI Link: 10.1063/1.5009009

Capture of CO₂ by a Cationic Ni^I Complex in the Gas Phase and Characterization of the Bound Activated CO₂ Molecule through Cryogenic Ion Vibrational Predissociation Spectroscopy

DOI Link: 10.1002/anie.201507965

Snapshots of Proton Accommodation at a Microscopic Water Surface: Understanding the Vibrational Spectral Signatures of the Charge Defect in Cryogenically Cooled H⁺(H₂O)_n=2-28 Clusters

DOI Link: 10.1021/acs.jpca.5b04355

Modes of Activation of Organometallic Iridium Complexes for Catalytic Water and C-H Oxidation

DOI Link: 10.1021/ic402390t

Vibrational manifestations of strong non-Condon effects in the H₃O⁺·X₃(X = Ar, N₂, CH4, H2O) complexes: A possible explanation for the intensity in the “association band” in the vibrational spectrum of water

DOI Link: 10.1039/C2CP24110B

Publications

2026

Spectroscopy and dynamics of the v = 1 levels derived from the OH(D) stretching modes in the I‾∙HDO complex using CW and time-resolved, resonant two-photon infrared excitation of the cryogenically cooled ions

Autobiography of Mark A. Johnson

Microcanonical Kinetics of Water-Mediated Proton Transfer in 4ABAH+‧(H2O)n=4-6 Clusters (ABA = Aminobenzoic Acid): A Model System for Size-Dependent Relaxation to Ergodic Behavior

2025

Dynamics of Protonated Oxalate from Machine-Learned Simulations and Experiment: Infrared Signatures, Proton Transfer Dynamics and Tunneling Splittings

Structural Insight into ESI+-Generated Ions of Oxazolochlorin Derivatives using Cryogenic Infrared Spectroscopy

Microcanonical Kinetics of Water-Mediated, Long Range Proton Transfer in Microhydrated 4-Aminobenzoic Acid

Cryogenic Ion Kinetics and Thermodynamics in a Temperature Controlled, Radiofrequency Ion Trap: A Case Study of the “Tag Isomers” Adopted by the Py-CH2-COOH+·D2 Cation

The onset for vibrationally-induced, intra-molecular proton transfer at three water molecules in microhydrated 4-aminobenzoic acid

Mechanism of a Halogen Exchange Reaction in Water: Catalysis by Aqueous Media

Isomers and band assignments in the cryogenic vibrational spectrum of the binary complex between water and protonated formic acid using two color, IR-IR photobleaching and H/D isotopic substitution

Characterization of two positional isomers of the Cs+Gly complex using two-color, IR-IR photobleaching of the cryogenically cooled ions

2024

Intramolecular Polarization Contributions to the pKa’s of Carboxylic Acids Through the Chain Length Dependence of Vibrational Tag-shifts in Cryogenically Cooled Pyridinium-(CH2)nCOOH (n = 1-7) Cations

Isomer-specific, Cryogenic Ion Vibrational Spectroscopy Investigation of D2- and N2- Tagged, Protonated Formic Acid Complexes Using Two Color, IR-IR Photobleaching

Demonstration of Capture, Cooling, Tagging, and Spectroscopic Characterization of UV Photoproduct Ions in a Cryogenic Ion Trap: Application to 266 nm Photofragment Ions from Rhodamine 6G

Measuring the Electric Fields of Ions Captured in Crown Ethers

Spectroscopic evidence for doubly hydrogen-bonded cationic dimers in the solid, liquid and the gaseous phases of carboxyl-functionalized ionic liquids

Hydrogen Tag Shifts as Vibrational Reporters for Positional Isomers of Formylphenides: Surprising Mobility of the Carbanion Center Upon Collisional Decarboxylation of the Parent Benzoates

2023

Characterization of the oxazolone and macrocyclic motifs in the bn (n = 2-5) product ions from CID of protonated oligoglycine peptides with isomer-selective, cryogenic vibrational spectroscopy

Intra-cluster charge migration upon hydration of protonated formic acid revealed by anharmonic analysis of cold ion vibrational spectra

Characterization of Oxidation Products from HOCl Uptake by Microhydrated Methionine Anions using Cryogenic Ion Vibrational Spectroscopy

Microcanonical Kinetics of Water-Mediated Proton Transfer in 4ABAH⁺‧(H₂O)_n=4-6 Clusters (ABA = Aminobenzoic Acid): A Model System for Size-Dependent Relaxation to Ergodic Behavior

Cryogenic Ion Kinetics and Thermodynamics in a Temperature Controlled, Radiofrequency Ion Trap: A Case Study of the “Tag Isomers” Adopted by the Py-CH₂-COOH⁺·D₂ Cation

Characterization of two positional isomers of the Cs⁺Gly complex using two-color, IR-IR photobleaching of the cryogenically cooled ions

Intramolecular Polarization Contributions to the pK_a’s of Carboxylic Acids Through the Chain Length Dependence of Vibrational Tag-shifts in Cryogenically Cooled Pyridinium-(CH₂)_nCOOH (n = 1-7) Cations

Isomer-specific, Cryogenic Ion Vibrational Spectroscopy Investigation of D₂- and N₂- Tagged, Protonated Formic Acid Complexes Using Two Color, IR-IR Photobleaching

Characterization of the oxazolone and macrocyclic motifs in the b_n (n = 2-5) product ions from CID of protonated oligoglycine peptides with isomer-selective, cryogenic vibrational spectroscopy