On a Research Rollercoaster With Friends

2D IR photon echo study of the anharmonic coupling in the OCN region of phenyl cyanate

“…Diagrams representing ground-state bleaching μ 0 j μ j 0 μ 0 i μ i 0 {0 i |00| j 0}, stimulated emission μ 0 i μ i 0 μ 0 i μ i 0 {0 i | ii|i 0}, excited-state absorption μ ik μ ki μ i 0 μ 0 i {0 i|ii|ki } and their coherence terms μ 0 j μ j 0 μ 0 i μ i 0 {0 i|ji|j 0} and μ ik μ kj μ j 0 μ 0 i {0 i|ji|ki } were included along with their nonrephasing counterparts, where i and j can be chosen as any of the V=0 → V=1 region states and k as any of the eigenstates involved in V=1 → V=2 region transitions of the OCN stretch. The inhomogeneous and homogeneous parameters, assuming Voigt profiles, were incorporated into the frequency domain responses[31] by averaging them (homogeneous damping parameters: 9, 9, and 8 cm −1 ) over gaussian distributions having widths of 12, 20, and 12 cm −1 for the 2236, 2265, 2281 cm −1 modes, respectively. For the water example, the homogeneous damping parameters were chosen as 9.5, 9.1, 7.4 cm −1 and the gaussian distributions widths as 9.1, 16.7, and 10.3 cm −1 .…”

Novel Pulsed Electron Paramagnetic Resonance Techniques for the Studies of Structure and Dynamics of Photo‐excited Triplet State of Organic Molecules: A Professional Journey

“…This was the first non‐magnetic‐resonance study to determine the ZFS of the photo‐excited triplet state of organic molecules. Many years later, I learned that Prof. Clyde Hutchison of the University of Chicago, the pioneer of the magnetic resonance study of the photo‐excited triplet state of organic molecules, assigned my JCP paper as one of the must‐read papers for his research group . I also applied the same high‐resolution optical technique to study the electronic structures of some nitrogen‐containing aromatic organic molecules: pyrazine, pyrimidine, and s ‐triazine .…”

Vibrational correlation between conjugated carbonyl and diazo modes studied by single- and dual-frequency two-dimensional infrared spectroscopy

“…Detailed computation protocols for simulating the response of a single vibrational mode have already been described in literature. [2,24,25] A key component is the frequency-frequency correlation function (FFCF), C(t), defined as (1) where is the frequency deviation from the average value at time t. To describe the dynamical property of individual vibrators, FFCF in the form of a single exponential decay or double exponential decays are often used. Here we utilized a double exponential form with fluctuation amplitudes (1, 2) and correlation times (1, 2) to simulate the results of single color experiments:…”

“…Since the development of coherent two-dimensional infrared (2D IR) spectroscopy more than ten years ago, [1] this powerful technique has revealed new structural and dynamic information in condensed phase systems through detailed measurements of vibrational couplings and dynamics. [2][3][4][5][6][7][8][9] Much of the information is hardly available from conventional techniques. For example, vibrational coupling is a major factor that governs 2D IR cross-peak patterns.…”

“…Many experimental and theoretical studies have shown that amide-I 2D IR spectra are very useful for elucidating structures of biological macromolecules. [2,5,10] Another example is to directly probe ultrafast chemical exchange processes through waiting-time dependent 2D IR. [7,[11][12][13][14][15] In this work, we will focus on vibrational frequency correlation.…”