XPP | New ‘Molecular Movie’ Reveals Ultrafast Chemistry in Motion

my name is Michael Minetti I'm a staff

scientist here at LCLs at SLAC National

Accelerator Laboratory and I am the

department head for the soft x-ray

department at LCLs so we here for the

very first time at LCLs we have taken a

molecular movie of a gas based chemical

reaction using the ultra-fast

capabilities of LCLs we chose to look at

and monitor a chemical by the name of

1/3 cyclohexane because the reaction is

quite well known over the last 30 or 40

years that this this molecule undergoes

a ring altering or a structural changing

event when optical laser lightish sign

upon it these type of ring opening

reactions are very common even in a

natural product biology but what wasn't

known are the exact time scales at which

how these structural dynamics occur and

how the structure actually evolves in

time to take these images we use a

technique called x-ray scattering as the

molecules populate a custom-built

scattering x-ray scattering vessel as

the x-rays progressed through the target

molecule they scatter and as this

scattering pattern occurs the x-rays or

the scattered x-rays are collected on a

large area x-ray detector so as these

things scatter on the detector their

positions are very meaningful and that's

how you infer back what's going on in

the molecules as its structure is

evolving so we produced a molecular

movie by looking at a series of time

delay pictures probed by the x-ray poles

so we have an optical pulse that sets

the reaction of foot and then we come

with this ultra bright source in LCLs

and we take little snapshots at

different time delays between the

optical pulse and the x-ray that being

LCLs and then we saw these frames

individual frames back together and we

were able to watch this chemical

reaction unfold on a very fast timescale

this is on the order of 100 to 200

quadrillions of a second or a sliver of

time or 200 millionth of a billionth of

a second

these results are very significant to

the LCLs because when LCLs was first

envisioned designed an x-ray source I

had the brightest x-rays in coming in

the small slivers of time they wanted to

look at molecular reactions in real time

and try to film these molecules in

action and again to make a molecular

movie I believe the the selling point

for LCLs when LCLs was first made it was

capturing the ultra small on the ultra

fast and we have done both in this

experiment

 SLAC National Accelerator Laboratory