Physics : Paper on a new topic

En français
It has been a long time since the last update on my research. The research previously discussed on the

CLF annual report 2009-2010 post has been pursued further leading to the publication of my first PRA paper last July. It explains in details the theory behind the "Molecular Siegert states in an electric field". We developed the Siegert states method applied to molecular system and obtained orientation-dependent and electric field-dependent energies and ionization rates for the ground state and degenerate first excited states of H₂⁺. The  results are compared with energies obtained from perturbation theory and

 the ionization rates obtained from the recently developed asymptotic theory.

The article can be found here.

Physics : CLF annual report 2009-2010

En français
It has been a long time since I posted about my work. For the past year I have been working in Japan on a brand new project. I am now studying the ionization of molecules (H2+) in electric field. My worked involves a lot of programming and theory to be developed so getting results took a little bit of time. My first publication for this new work is now available. It's a CLF annual report paper of four pages. I expect to get something more consequent published in a journal within the next few months.

The paper can be found here. Look for Hamonou and you'll get to the page.

Physics : An other article published

En français
One other article has been published in "Journal Physics B : At. Mol. Opt. Phys". The title is : "Influence of autoionizing states on the pulse-length dependence of strong-field Ne⁺ photoionisation at 38.4 eV".

In this one the novelty is that we used the time-dependent R-matrix approach to investigate ionization of ground-state Ne⁺ for several laser field intensities. We discovered that the ionization probability oscillates with pulse length, which is due to population and depopulation of autoionizing states just above the Ne^{2 +} ground state, reached after absorption of a single photon. That's something new that hadn't been studied before.

The paper can be found here.

I'm a doctor

En français
So that's it, I finally finished my studies. Yesterday I had my VIVA (last exam of the PhD study for people who don't know what that is) and I passed with few corrections to make to my manuscript.
I'm now doctor in physics, don't come to see me if you're sick, I can't do anything about it.
You can see that the title of the thesis is "Inner-shell processes in two-photon ionisation of ions by VUV laser light"

So here is the PhD in numbers :

_ 3 years of hard work
_ 2 papers published out of my work
_ 2 more should be publish in the next few months
_ 5 posters
_ 9 conferences attended (3 talks)
_ 161 pages of thesis
_ 2 hours and 10 minutes of questioning (VIVA)
_ and lots of friends made on the way.

Update on the Mg paper

En français
Hi, just a little special post here to say that my Mg paper ("Satic and dynamic polarisabilities of Mg-like ions") appears now on the featured article list of Journal of Physics B : Atome, Molecular and Optical Physics.
What featured article means is :"These high-interest recent articles are all free to read."
So the period of free reading of the paper has been extended.

Physics : My fourth article has been published

En français
My fourth article has been published in "Journal Physics B : At. Mol. Opt. Phys". The title is : "Static and dynamic polarisabilities of Mg-like ions". So obviously it follows the first one "Static and dynamic polarizabilities of Na-like ions".


In it we describe the investigation of the static and frequency-dependent dipole polarizabilities for the ground state of neutral Mg, Al⁺, Si²⁺, P³⁺ and S⁴⁺.
We use a code called CIVPOL, a version of the famous CIV3 code, able to calculate polarizabilities.
CIV3 is very useful to me has it calculate the orbitals I need to perform my R-matrix calculations.


The full text will be free to access for one month here.

Physics : My third poster

En français
This is the poster I presented last week in Dresden.
I have been there for two weeks.
The first week was dedicated to summer school and the second was a workshop on Time-Resolved X-Ray Dynamics.
I learned a lot and made a lot of friends.

My poster doesn't show much different things compared to the two previous, except a graph showing the radio Ne2+/Ne+.
The slope compare well with experiment but the values are a bit to low. That is due to the fact the those calculations have been made with rates obtained by emission of a 2p electron only.
This week I hope to have enough data from my intensity dependent calculations to recalculate this ratio using the ionization rates including emission of a 2p or 2s electron.

Those two weeks in Dresden were very profitable, I hope to go more often to that kind of interesting conference in the future.

Physics : PhD, Second year presentation.

En français

Yesterday I made my PhD second year presentation.
I explained everything I have done so far about the two-photon ionization of Ne+.
I show the energies and ionization rates obtained to demonstrate the importance of emission of inner-shell electrons, when the ion is irradiated by an intense laser field.
I also show that we can conclude about double sequential ionization of Ne by knowing the state in which is left Ne2+.
To see the presentation follow the link bellow.

PhD Second Year Presentation

Physics : My third article has been published

En français

My third article has been published as a Fast Track Communication.
The title is : "On the importance of inner-shell contributions to multiphoton ionization of complex atoms in the VUV regime"
It follows the second one : "Two-photon emission of a 2p electron from Ne+ and consequences for sequential double ionization of Ne"

Using the R-matrix-Floquet approach, we studied the two-photon ionization of ground-state Ne+ irradiated by a laser light of intensity 10^14 W.cm-2.
The importance of the contribution of emission of a 2s electron is demonstrated by comparing the ionization rates obtained for emission of a 2p electron only with ionization rates obtained for emission of 2p and 2s electron.
We find that the ionization rate is enhanced by an order of magnitude when inner-shell processes are included.

The full text will be free to access for one month here.

Physics : My second poster

En français
This is my second poster. I presented it last September in London for the paqconf conference. The conference was presenting three different topic, laser physics, quantum optics and quantum information.
My poster was about inner-shell processes in Ne+.
We compare the different spectrums obtain when we describe the Ne2+ target states differently, either with 3, 4 or 5 target states.
In the first case, only a 2p electron can be emitted from Ne+, in the others we can have emission of 2p or 2s electron.
The emission of the 2s electron is an inner-shell process and it is shown to be the dominant process.
The spectrums obtained are very different, the possibility of emitting a 2s electron increase a lot the ionisation rates. The agreement with experiment is also better when the target state is described more in details.
At the end of the conference we had a dinner on a boat side seeing London.


Travel table of content

Physic : My first Poster

En français

This is my first poster. It was presented by my supervisor in Freiburg (Germany) at the ICPEAC conference in 2007.
We used the R-matrix Floquet theory to study the two-photon ionization of the Ne+ ion. When an atom is placed in a laser field, it can absorbed some photons and be ionized.

On the poster, we represented graphs for emission of a 2p electron only. We studied the inner-shell processes, that the emission of a 2s electron later.
On the first graph, I represented the dressed energies for M=0 and M=1. We see some differences due to the different symmetries allowed. On the second and third graph, we can see the spectrum for M=0 and M=1.
On the fourth and fifth graph we can see the probabilities of leaving the residual Ne2+ ion in his ground state 3Pe or two lower excited states 1De or 1Se.

I like Ne+, it is great fun to study it. There is so many things going on.

First Conference and Giant Causeway

En français Last week, on Wednesday, I gave my first conference. That was OK but also a bit (very) scary. First of all I was suppose to speak at 2.30 pm, so to be the second speaker of the day. The problem was that my supervisor couldn't make it on time, so I was moved to 8.35 pm, that is that I gave the last talk. I had all the day to be under pressure. I was doing fine until the last session. I was really scared and shaking like crazy during the two talks before mine. Hopefully, I don't know how but I managed to calm down before giving my talk, and did it well. I was feeling much better afterwards. My talk title was : "Inner-shell processes in Ne+ at photon energies between 25 and 41 eV". Apparently I was a bit confusing when talking about threshold. Then on Friday we had the trip to Giant Causeway. It was raining at the beginning but then sunny, the wind was so strong that I managed to dry and I also was even thinking I was going to fly away. Giant Causeway is one of The 1000 Natural Wonder Of The World You Must See. 999 to go. It's really a beautiful landscape. Travel table of content