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<span style="font-family: "Times New Roman", serif; font-size: 12pt; color: rgb(0, 0, 10);">Dear all,</span></p>
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<span style="font-family: "Times New Roman", serif; font-size: 12pt; color: rgb(0, 0, 10);">Dr. Xu-Cheng He’s group at the Institute for Atmospheric and Earth System Research (INAR), University of Helsinki, invites applications for two postdoctoral researcher
positions, each for a two-year term with the possibility of extension subject to funding availability. Applicants should have obtained their PhD within the past three years, excluding parental leave. Applicants who are able to join the group between October
2025 to March 2026 will be considered. Review of applications begins immediately. Applications will be accepted until the positions are filled. Updates will be posted
</span><span style="font-family: "Times New Roman", serif; font-size: 12pt; color: purple;"><u><a href="https://www.xuchenghe.science/" data-outlook-id="eee11885-2068-43aa-8e8c-48d8f5f503a9" style="color: purple; margin-top: 0px; margin-bottom: 0px;">here</a></u></span><span style="font-family: "Times New Roman", serif; font-size: 12pt; color: rgb(0, 0, 10);">.</span></p>
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<span style="font-family: "Times New Roman", serif; font-size: 12pt; color: rgb(0, 0, 10);">The first position focuses on gas-phase isoprene oxidation under upper tropospheric conditions, combining mass spectrometric methods with kinetic modelling. This position
aims to understand the chemical mechanisms behind our recent finding of </span><span style="font-family: "Times New Roman", serif; font-size: 12pt; color: purple;"><u><a href="https://www.nature.com/articles/s41586-024-08196-0" data-outlook-id="d702d9db-fcfb-44b5-b803-8555c1473fb2" style="color: purple; margin-top: 0px; margin-bottom: 0px;">new
particle formation from isoprene oxidation products</a></u></span><span style="font-family: "Times New Roman", serif; font-size: 12pt; color: rgb(0, 0, 10);">. The successful candidate will work with chemical ionisation mass spectrometer systems, including
time-of-flight mass spectrometer and the recently developed </span><span style="font-family: "Times New Roman", serif; font-size: 12pt; color: purple;"><u><a href="https://www.karsa.fi/research/bundles" data-outlook-id="85312087-3599-4886-a3c7-601dadc9fc3a" style="color: purple; margin-top: 0px; margin-bottom: 0px;">MION2-Orbitrap
system</a></u></span><span style="font-family: "Times New Roman", serif; font-size: 12pt; color: rgb(0, 0, 10);">. The role also involves participation in the
</span><span style="font-family: "Times New Roman", serif; font-size: 12pt; color: purple;"><u><a href="https://home.cern/science/experiments/cloud" data-outlook-id="fe33713c-b951-45bd-82d5-d48361bc5343" style="color: purple; margin-top: 0px; margin-bottom: 0px;">CLOUD
project at CERN</a></u></span><span style="font-family: "Times New Roman", serif; font-size: 12pt; color: rgb(0, 0, 10);"> for approximately 4–6 weeks per year, with additional compensation provided.</span></p>
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<span style="font-family: "Times New Roman", serif; font-size: 12pt; color: rgb(0, 0, 10);">The second position is more broadly defined, with potential research topics including:</span></p>
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<span style="font-family: "Times New Roman", serif; font-size: 12pt; color: rgb(0, 0, 10);">1) Iodine particle formation mechanisms in the atmosphere.</span></p>
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<span style="font-family: "Times New Roman", serif; font-size: 12pt; color: rgb(0, 0, 10);">2) Modelling impacts of isoprene new particle formation.</span></p>
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<span style="font-family: "Times New Roman", serif; font-size: 12pt; color: rgb(0, 0, 10);">3) Multi-phase chemistry of isoprene oxidation products</span></p>
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<span style="font-family: "Times New Roman", serif; font-size: 12pt; color: rgb(0, 0, 10);">4) Modelling impacts of iodine and/or sulfur new particle formation.</span></p>
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<span style="font-family: "Times New Roman", serif; font-size: 12pt; color: rgb(0, 0, 10);">5) Aerosol vertical measurements using drone systems.</span></p>
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<span style="font-family: "Times New Roman", serif; font-size: 12pt; color: rgb(0, 0, 10);">The annual salary for these positions is approximately €45,000 (ca. $52,500). For reference, the monthly rent of a one-bedroom apartment within a 20-minute commute to
the campus typically ranges from €600 to €1,000. Finland offers one of the world’s most advanced
</span><span style="font-family: "Times New Roman", serif; font-size: 12pt; color: purple;"><u><a href="https://www.workinfinland.com/en/why-finland/living-in-finland/welfare-and-benefits/" data-outlook-id="1bb79294-4eb4-4cff-ba04-fdea9bcec21a" style="color: purple; margin-top: 0px; margin-bottom: 0px;">social
welfare systems</a></u></span><span style="font-family: "Times New Roman", serif; font-size: 12pt; color: rgb(0, 0, 10);">, and the University provides comprehensive staff benefits in addition to the national benefits (see
</span><span style="font-family: "Times New Roman", serif; font-size: 12pt; color: purple;"><u><a href="https://www.helsinki.fi/en/about-us/careers/why-university-helsinki/staff-benefits" data-outlook-id="84924215-e061-4330-87ff-87ee3c3f9c36" style="color: purple; margin-top: 0px; margin-bottom: 0px;">here</a></u></span><span style="font-family: "Times New Roman", serif; font-size: 12pt; color: rgb(0, 0, 10);">).
Paid annual leave ranges from 22 to 30 days, depending on years of service.</span></p>
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<span style="font-family: "Times New Roman", serif; font-size: 12pt; color: rgb(0, 0, 10);">Interested candidates are welcome to contact Dr. Xu-Cheng He (xucheng.he@helsinki.fi). Please combine the following materials into a single PDF and attach it to your
email:</span></p>
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<span style="font-family: "Times New Roman", serif; font-size: 12pt; color: rgb(0, 0, 10);">1) CV</span></p>
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<span style="font-family: "Times New Roman", serif; font-size: 12pt; color: rgb(0, 0, 10);">2) One-page personal statement. Please include your research interests, research experience, and future research plans</span></p>
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<span style="font-family: "Times New Roman", serif; font-size: 12pt; color: rgb(0, 0, 10);">3) Contact details for three references</span></p>
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<span style="font-family: "Times New Roman", serif; font-size: 12pt; color: rgb(0, 0, 10);">Short bio of the PI:</span></p>
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<span style="font-family: "Times New Roman", serif; font-size: 12pt; color: purple;"><u><a href="https://www.xuchenghe.science/" data-outlook-id="5a955292-2119-4afa-b03b-02207ba71f65" style="color: purple; margin-top: 0px; margin-bottom: 0px;">Dr. Xu-Cheng
He</a></u></span><span style="font-family: "Times New Roman", serif; font-size: 12pt; color: rgb(0, 0, 10);"> is an Academy Research Fellow (research-track) and doctoral student supervisor at University of Helsinki. He is also a group leader at the University
and co-PI for the </span><span style="font-family: "Times New Roman", serif; font-size: 12pt; color: purple;"><u><a href="https://home.cern/science/experiments/cloud" data-outlook-id="d8ea34af-9559-42e7-a9f6-3b33ee2c1db1" style="color: purple; margin-top: 0px; margin-bottom: 0px;">CLOUD
project at CERN</a></u></span><span style="font-family: "Times New Roman", serif; font-size: 12pt; color: rgb(0, 0, 10);">. His research combines state-of-the-art mass spectrometric methods, kinetic modelling, quantum chemical calculations, and Earth system
modelling to investigate and interpret the climate impact of atmospheric aerosol formation processes. </span></p>
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<span style="font-family: "Times New Roman", serif; font-size: 12pt; color: rgb(0, 0, 10);">Best,</span></p>
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<span style="font-family: "Times New Roman", serif; font-size: 12pt; color: rgb(0, 0, 10);">Xu-Cheng</span></p>
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