# ultrafast

## Conversion Factors

Some useful conversion factors from my graduate school days.

## Derivation of the Transform Limit

Here I derive the somewhat well known formula that for a transform limited pulse the bandwidth duration product is 15 ps cm$^{-1}$

## Difference Bands TCNE

The time-resolved femtosecond stimulated Raman spectra (FSRS) of a charge transfer (CT) excited noncovalent complex tetracyanoethylene:1-chloronaphthalene (TCNE:ClN) in dichloromethane (DCM) is reported with 40 fs time resolution. In the frequency …

## Good vibrations?

What role do vibrational coherences, if any, play in condensed phase photoreactivity? While we have observed vibrational coherences in almost any system where we look hard enough, it hasn't been clear if these are a cause or consequence of reactivity. In this survey of our own work we argue that for fast reactions (

## Ring Opening

Two-dimensional femtosecond stimulated Raman spectroscopy (2D-FSRS) is used to probe the structural evolution of a modified cyclohexadiene as it undergoes a photoinduced ring opening reaction. Analysis of the excited state stimulated Raman …

## Observing a reactive conical intersection

We develop 2D-FSRS and use it to probe the conical intersection (CI) of a model photochemical reaction. In the end we were able to identify the two primary modes, the coupling and tuning modes, which comprise the CI and drive the reaction.

## Ndab Isrs

Azobenzenes are versatile photoswitches that find application in optical memory, light-driven motors, and molecular gating. Despite many studies, the molecular details of their light induced trans to cis isomerization are still debated. To inform …

## Etalon Fsrs

A comparison between a Fabry-Pérot etalon filter and a conventional grating filter for producing the picosecond (ps) Raman pump pulses for femtosecond stimulated Raman spectroscopy (FSRS) is presented. It is shown that for pulses of equal energy the …

## Dye Sensitized Fsrs

Interfacial electron transfer between sensitizers and semiconducting nanoparticles is a crucial yet poorly understood process. To address this problem, we have used transient absorption (TA) and femtosecond stimulated Raman spectroscopy (FSRS) to …

## Ndab

Azobenzenes are used in many applications because of their robust and reversible light induced trans [leftrightharpoons] cis isomerization about the N[double bond, length as m-dash]N bond, but the mechanism of this ultrafast reaction has not been …