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Photochemistry (PC)


Admission requirements

Core course in MSc Chemistry – Energy & Sustainability, elective course MSc Chemistry, MSc Life Science and Technology
Students with a BSc in MST with a major in Chemistry/materials or BSc LST with a minor advanced LST are better prepared for the PC course. Other students with an equivalent BSc should have a basic knowledge in quantum chemistry (atomic s, p, d orbitals, molecular orbitals, meaning of the wave function), organic chemistry (covalent bond, pi systems and conjugation), inorganic chemistry (crystal field theory), chemical kinetics (1st and 2nd order rate laws, elementary processes, transition states), and biochemistry (structure of proteins, lipids, and nucleic acids). A crash course in chemical kinetics and in electrochemistry is provided at the beginning of the course.


Photochemistry studies the action of light on molecules. Understanding photochemistry allows for explaining light-driven phenomena occurring in nature such as vision or photosynthesis; to study cells, materials, or chemical reactions by using fluorophores, imaging agents, or time-dependent spectroscopy; and to develop synthetic light-responsive systems for curing diseases or making solar fuels. Photochemistry is governed by quantum chemistry, excited states, and orbitals. It spans 15 orders of magnitude of time scale range, from femtoseconds for photon absorption to minutes or hours for photoreactions or phosphorescence.

In the PC course basic photochemistry concepts such as excited state multiplicity, photoreaction and emission quantum efficiency, or excited state lifetimes, are first explained. Then, a range of different elementary processes that can follow molecule excitation, are described, including for example emission, non-radiative relaxation, and a range of photoreactions such as electron transfer, energy transfer, or ligand photosubstitution reactions.

Two lectures are dedicated to the theoretical modeling of excited states using quantum calculations and the theory of electron transfer (Marcus theory); a computer lab is organized to introduce the students in a practical manner to the representation and modeling of excited states. One course is dedicated to time-dependent spectroscopy for the study of photocatalytic and phototherapeutic compounds. Then, the principles of photoredox catalysis and their application for the sustainable production of solar fuels and artificial photosynthesis are discussed. Finally, the last part of the course is dedicated to the role of photochemistry in biology. This includes a short study of vision, followed by the description of Förster energy transfer probes for the study of biomolecules and biological processes. A special final lecture is dedicated to photodynamic therapy in cancer treatment, photoactivated chemotherapy, and optogenetics.

Course objectives

  • To understand the concept of excited state and to know the different methods available to represent them

  • To have an overview of the different elementary processes that can occur following photon absorption by a molecule

  • To be able to write the equation describing the kinetics of elementary photochemical processes (photon absorption, transition between excited states, 1st and 2nd order photoreaction)

  • To be able to retrieve or calculate quantum yields from experimental data

  • To understand double bond photoisomerization reactions and ligand photosubstitution reactions of transition metal complexes

  • To interpret time-resolved absorption and emission spectroscopy data

  • To know the different methods available to simulate excited states with computers

  • To understand energy transfer (Förster, Dexter)

  • To understand electron transfer (Marcus theory)

  • To have minimal knowledge about redox potentials in the ground and in the excited state

  • To understand charge recombination and how to minimize it

  • To understand photocatalytic reactions and mechanisms (oxidative vs. Reductive quenching)

  • To understand the basics concept of artifical photosynthesis and solar fuel production

  • To know how to study biological processes using photochemistry (bioimaging)

  • To know basic concepts for phototherapy and photopharmacology

  • To improve writing skills for a scientific report


Schedule information can be found on the website of the programmes.

You will find the timetables for all courses and degree programmes of Leiden University in the tool MyTimetable (login). Any teaching activities that you have sucessfully registered for in MyStudyMap will automatically be displayed in MyTimeTable. Any timetables that you add manually, will be saved and automatically displayed the next time you sign in.

MyTimetable allows you to integrate your timetable with your calendar apps such as Outlook, Google Calendar, Apple Calendar and other calendar apps on your smartphone. Any timetable changes will be automatically synced with your calendar. If you wish, you can also receive an email notification of the change. You can turn notifications on in ‘Settings’ (after login).

For more information, watch the video or go the the 'help-page' in MyTimetable. Please note: Joint Degree students Leiden/Delft have to merge their two different timetables into one. This video explains how to do this.

Mode of Instruction

Lectures, paper discussion, and exercise correction (14 sessions), and a computer lab (1 session)

Assessment method

Written examination (80%) and computer lab report (20%)

Reading list

The course is based on the slides discussed during the courses, videos of the courses available to all registered students, and exercises and old exams corrected together in class.
The following book is recommended: Vincenzo Balzani, Paola Ceroni, Alberto Juris (2014) Photochemistry and Photophysics, Concepts, Research, Application, Wiley VCH (ISBN: 978-3-527-33479-7).


From the academic year 2022-2023 on every student has to register for courses with the new enrollment tool MyStudyMap. There are two registration periods per year: registration for the fall semester opens in July and registration for the spring semester opens in December. Please see this page for more information.

Please note that it is compulsory to both preregister and confirm your participation for every exam and retake. Not being registered for a course means that you are not allowed to participate in the final exam of the course. Confirming your exam participation is possible until ten days before the exam.

Extensive FAQ's on MyStudymap can be found here.


Dr. Sylvestre Bonnet, Dr. F. Buda


Assignment deadlines are communicated via Brightspace.

According to OER article 4.8, students are entitled to view their marked examination for a period of 30 days following the publication of the results of a written examination. Students should contact the lecturer to make an appointment for such an inspection session.