Astrophysically small molecules exist not just in quiescent cool clouds, which themselves are weakly ionized and therefore contain electrons, but also in much more active astrophysical regions such as planetary nebulae and diffuse interstellar clouds. These regions often contain significant numbers of free, quasi-thermal electrons, up to 10-4 compared to H2. These electrons can effect chemical change and drive observable spectroscopy processes (see A.J. Lim, I. Rabadan and J. Tennyson, MNRAS, 306, 473 (1999) for example); the cross sections between electrons and molecular ions are particularly large. Additionally electron molecule collisions are important elsewhere, for example they are the main driver behind planetary aurorae and many molecular masers. Models of all these regimes require data which is largely unknown and, in many cases, cannot be determined from laboratory based measurements. Over the last two decades the UCL group has developed the UK molecular R-matrix codes to provide a first principles, quantum mechanical treatment of the collision between low energy electrons and small molecules. This code has been used to treat collisions leading to rotational excitation involving important astrophysical ions (see for example A. Faure and J. Tennyson, MNRAS, 325, 443 (2001), A. Faure, J.D. Gorfinkiel and J. Tennyson, MNRAS 347, 323 (2004)). Recent observations of molecular emissions from C-shocked regions of the ISM (Jimenez-Serra et al, ApJ 650, L135 (2007)) showed that it is possible to recover local electron densities by using our electron molecule collisions calculations. Low-energy electrons also destroy molecules through dissociative recombination (DR for ions) and dissociative attachment (DA for neutrals). Cross sections for these processes are often hard to obtain. The present proposal is for a PhD student who will use the QuantemolN implementation of the UK polyatomic R- matrix code to study electron collisions with molecules of astrophysical interest and obtain dissociative cross sections. To do this the student will develop and test an add-on DA/DR estimator for Quantemol-N. A preliminary DA estimator developed by the company will provide the starting point for this work. The QuantemolN code, which will be provided by the company, is very suitable for these studies since it is an expert system which greatly increases the ease and speed with which a user can perform very technically demanding electron collision calculations. In return the student will assist the company in adding further features to this code to treat DA and DR. This project is proposed now since this feature has recently been requested by a Japanese industrial client of the company and a number of other users have expressed a strong interest. Adding to this functionality of the code is a strategic aim of Quantemol. The student will be provided training in performing electron molecule collision calculations, interpreting the results and using them in astronomical models and to interpret astronomical spectra. S/he will interact with people directly observing the processes, several of whom (for example Dr J Rawlings and Dr S Viti) are at UCL. S/he will also experience working with a small start up company which gives the opportunity to be involved both in the software development and in the interaction with other users of the code. This proposal follows a highly successful CASE studentship award to Dr HN Varambhia who used Quantemol-N to do studies on HCN, HNC, CS, CO and other astrophysically important systems (Eg Varambhia et al, Electron-impact rotational excitation of the carbon monosulfide (CS) molecule, MNRAS in press) which has been of immense benefit to the company by raising its scientific profile which led to new orders for the existing Quantemol-N package and interest in the others, from both the UK and abroad. Varambhia also added an electron impact ionization estimator to Quantemol-N.

There is a growing realisation that small molecules exist not just in quiescent cool clouds but also in much more active astrophysical regions such as planetary nebulae and diffuse interstellar clouds. These regions often contain significant numbers of free, quasi-thermal electrons, up to 10-4 compared to molecular hydrogen. These electrons can effect chemical change and drive observable spectroscopy processes (see A.J. Lim, I. Rabadan and J. Tennyson, MNRAS, 306, 473 (1999) for example); the cross sections between electrons and molecular ions are particularly large. Additionally electron molecule collisions are important elsewhere, for example they are the main driver behind planetary aurorae and many molecular masers. Models of all these regimes require data which is largely unknown and, in many cases, cannot be determined from laboratory based measurements. Over the last two decades the UCL group has developed the UK molecular R-matrix codes to provide a first principles, quantum mechanical treatment of the collision between low energy electrons and small molecules. This code has been used to treat collisions leading to rotational excitation involving important astrophysical ions (see for example A. Faure and J. Tennyson, MNRAS, 325, 443 (2001)) and the strongly dipolar water molecule (A. Faure, J.D. Gorfinkiel and J. Tennyson, MNRAS 347, 323 (2004)). However these treatments are still very limited in their scope. Thus, for example, calculations on electron collisions with water which are important for models of water masers and cometary emissions, and will undoubtedly be needed to interpret observations from ESA's forthcoming Herschel mission, need to be extended to treat both much higher rotational levels and vibrational motion. Recent observations of molecular emissions from C-shocked regions of the ISM (Jimenez-Serra et al, ApJ 650, L135 (2007)) showed that it is possible to recover local electron densities by using electron molecule collisions calculations (this work used ones performed by the proposer). The present proposal is for a PhD student who will use the QuantemolN implementation of the UK polyatomic R- matrix code to study electron collisions with molecules of astrophysical interest such as OH and SiO. Similar electron collisions with C2, important in cometary tails and elsewhere, will also be attempted. The QuantemolN code, which will be provided by the company, is very suitable for these studies since it is an expert system which greatly increases the ease and speed with which a user can perform very technically demanding electron collision calculations. In return the student will assist the company in adding further features to this code, for example to treat rotational and vibrational excitation. Adding to the functionality of the code is a strategic aim of Quantemol. The student will be provided training in performing electron molecule collision calculations, interpreting the results and using them in astronomical models and to interpret astronomical spectra. S/he will interact with people directly observing the processes, several of whom (for example Dr J Rawlings and Dr S Viti) are at UCL. S/he will also experience working with a small start up company which gives the opportunity to be involved both in the software development and in the interaction with other users of the code. This proposal follows a highly successful CASE studentship award (now in its final year) to Mr HN Varambhia who has both QuantemolN to do studies on HCN, HNC, CO and other astrophysically important systems (Eg Varambhia et al, Electron-impact rotational excitation of HCN, HNC, DCN and DNC, MNRAS in press) which has been of immense benefit to the company by raising its scientific profile which led to new orders for the existing Quantemol-N package and interest in both Quantemol-N and Quantemol-P from both the UK and abroad.

The dynamics of quantum particles is the basis to describing the material world. Collisions between nuclei provides basic chemical reactivity, while the movements of electrons around nuclei provides the fine mechanistic details. To understand these motions we need to solve the time-dependent Schroedinger equation - a non-trivial problem for more than 3 particles that requires a huge computational effort. State-of-the art experiments using attosecond or femtosecond pulses of radiation allow us to follow the motion of these particles, but without computer simulations the results are difficult to understand. This field of research is presently undergoing a huge expansion, due to the provision of new light sources such as free electron lasers (FELs), and software needs to be developed to keep up to the new capabilities. CCPQ has two community codes (R-matrix suite, MCTDH wavepacket dynamics) to treat these processes. The results give a deep inside into the fundamental reactivity of molecules, where quantum mechanical behaviour must be considered. The interactions of anti-matter particles are also a topic of much interest, primarily due to the use of positrons in medical imaging, but also as a field of fundamental science in experiments such as the ALPHA project. Here, anti-matter particles are collided with normal matter and the different decay channels investigated. CCPQ is developing a code in collaboration with experimentalists to help understand the behaviour of these exotic sounding, but useful, particles. Going from few bodies to many-bodies introduces some of the most fascinating phenomena in physics, such as superfluidity, superconductivity and ferroelectricity. However, to directly simulate them also introduces an exponentially scaling overhead in computation effort with the system size. While usually the preserve of condensed matter systems such strongly-correlated physics, where particles behaviour collectively, are now accessible in controlled ways with cold-atoms trapped in optical lattices. This has opened up previously inaccessible coherent dynamics in many-body systems to experimental scrutiny, such as examining what happens if the interaction and kinetic energies of particles are quenched across a quantum phase transition. The advances of this unique perspective are now reciprocating back to condensed matter problems where interaction of THz radiation on femtosecond timescales is also revealing correlated coherent electrons motion in solid-state systems. This topic of strongly-correlated many-body dynamics is the final strand of CCPQ development - embodied by the TNT project which introduces new ways of compressing many-body states to overcome the exponential barrier. It will support not only the emerging quantum technology of cold-atom quantum simulation, but also may eventually aid in designing and controlling real materials where optical pulses can switch properties such as superconductivity or ferroelectricity with great technological potential. CCPQ supports the development of these world leading community codes by providing a forum for the exchange of ideas, by providing networking opportunities for researchers to help disseminate the codes, and by supporting training workshops for users of the codes. It also provides direct support in the form of computer experts at the Daresbury laboratory who help optimise the codes for use on large high performance computers (HPC).

The dynamics of quantum particles is the basis to describing the material world. Collisions between nuclei provides basic chemical reactivity, while the movements of electrons around nuclei provides the fine mechanistic details. To understand these motions we need to solve the time-dependent Schroedinger equation - a non-trivial problem for more than 3 particles that requires a huge computational effort. State-of-the art experiments using attosecond or femtosecond pulses of radiation allow us to follow the motion of these particles, but without computer simulations the results are difficult to understand. This field of research is presently undergoing a huge expansion, due to the provision of new light sources such as free electron lasers (FELs), and software needs to be developed to keep up to the new capabilities. CCPQ has two community codes (R-matrix suite, MCTDH wavepacket dynamics) to treat these processes. The results give a deep inside into the fundamental reactivity of molecules, where quantum mechanical behaviour must be considered. The interactions of anti-matter particles are also a topic of much interest, primarily due to the use of positrons in medical imaging, but also as a field of fundamental science in experiments such as the ALPHA project. Here, anti-matter particles are collided with normal matter and the different decay channels investigated. CCPQ is developing a code in collaboration with experimentalists to help understand the behaviour of these exotic sounding, but useful, particles. Going from few bodies to many-bodies introduces some of the most fascinating phenomena in physics, such as superfluidity, superconductivity and ferroelectricity. However, to directly simulate them also introduces an exponentially scaling overhead in computation effort with the system size. While usually the preserve of condensed matter systems such strongly-correlated physics, where particles behaviour collectively, are now accessible in controlled ways with cold-atoms trapped in optical lattices. This has opened up previously inaccessible coherent dynamics in many-body systems to experimental scrutiny, such as examining what happens if the interaction and kinetic energies of particles are quenched across a quantum phase transition. The advances of this unique perspective are now reciprocating back to condensed matter problems where interaction of THz radiation on femtosecond timescales is also revealing correlated coherent electrons motion in solid-state systems. This topic of strongly-correlated many-body dynamics is the final strand of CCPQ development - embodied by the TNT project which introduces new ways of compressing many-body states to overcome the exponential barrier. It will support not only the emerging quantum technology of cold-atom quantum simulation, but also may eventually aid in designing and controlling real materials where optical pulses can switch properties such as superconductivity or ferroelectricity with great technological potential. CCPQ supports the development of these world leading community codes by providing a forum for the exchange of ideas, by providing networking opportunities for researchers to help disseminate the codes, and by supporting training workshops for users of the codes. It also provides direct support in the form of computer experts at the Daresbury laboratory who help optimise the codes for use on large high performance computers (HPC).

In this project, we will develop new software for the accurate description of atoms and molecular systems in intense, ultra-short light fields with arbitrary polarisation. This involves generalising two world-leading suites of codes: The R-matrix with time-dependence codes (RMT) for ultra-fast atomic dynamics and the UKRmol+ suite for electron/positron scattering and photoionisation processes in molecules. By making these codes available to the wider community, in a form that can be easily used and efficiently run, we will help build the software infrastructure in the UK. Significant development in laser technology over the last couple of decades has led to the birth of attosecond science: lasers are now available that can produce extremely short pulses (around 0.1 femtosecond or 10(-16) s in duration) to image and control the motion of electrons in atoms and molecules. This development has, for example, enabled scientists to 'see' how charge is transferred in a molecule after it is ionised, a process that has biological importance (for example, in photosynthesis). Light can be treated as an electromagnetic wave; the direction in which the electric field oscillates defines the polarisation of the light. This polarisation, in turn, determines how the light interacts with matter. Until very recently intense, ultra-short light pulses were linearly polarised. However, it has recently become possible to generate laser pulses with different types of polarisation. New scientific research areas and new opportunities have become available via these latest technological developments. With control over the polarisation of light pulses, one can control the electron dynamics and even fine-tune it: In simple terms, using light pulses which oscillate in more than one-dimension gives an additional control parameter in experiments, and this is the underlying mechanism in so-called multidimensional spectroscopy. This field is becoming increasingly interesting, as experiments begin to probe the interface of the quantum and classical worlds. In addition, light pulses with elliptical polarisation will enable the detailed study of electron dynamics in chiral molecules. (Chiral molecules are those that cannot be superimposed to their mirror images, like human hands). These molecules are immensely interesting: a lot of biologically important molecules, like the amino acids and sugars that are building blocks of living organisms are 'homochiral': only one variant is present in life (but never its mirror image). New computer codes, which can handle general atomic and molecular systems in arbitrarily polarised light are needed to complement experimental advances, to assist in their theoretical interpretation and also to guide them. At present, the RMT codes can model atoms in a linearly polarised light field. Expanding them to treat the effect of arbitrarily polarised light is a substantial task: It requires lifting symmetry restrictions which have limited the size of previous calculations, and consequently a significant improvement in the codes' efficiency to account for the much larger-scale calculations will be necessary. In addition, we will massively expand the impact of the method by developing an equivalent method to treat molecules in a time-dependent fashion. The data needed to study the effect of the laser pulses on molecules will be generated by the UKRmol+ suite. This, in turn, requires the overhauling of these codes so they can produce sufficiently accurate input in an efficient way. The computational development within this project will be strongly connected to the CCPQ community, which involves research groups across the UK developing scientific software for use in atomic and molecular physics and computational chemistry. Through CCPQ we will not only share the suites of codes, but also the expertise and software development skills gained.