Hi everyone!

I'd like to share ORCA PED Analyzer, an open-source tool I developed to simplify the analysis and assignment of vibrational calculations performed with ORCA.

The program performs Potential Energy Distribution (PED) analysis of harmonic normal modes and generates automatic vibrational assignments based on calculated atomic motion and internal-coordinate energy decomposition, rather than empirical frequency windows.

🔬 Main features

• PED analysis and automatic vibrational-mode assignment
• Detection and reporting of mixed modes
• Optional VPT2/GVPT2 integration
• Analysis of fundamentals, overtones and combination bands
• Harmonic and anharmonic IR intensities, when available
• Generation of broadened IR spectra
• CSV export
• Avogadro CJSON export for visualization of normal modes
• Both GUI and command-line interfaces
• Pre-built applications for Linux, Windows and macOS

🔗 Software

GitHub:
https://github.com/SebRoLENS/orca-ped-analyzer

The software is open source (MIT) and archived on Zenodo with a DOI.

⚠️ A note about the development

I am an experimental physical chemist, not a computational chemist or a professional software developer. However, I regularly use computational chemistry software as part of my research, and ORCA PED Analyzer was originally developed to address some of my own needs in vibrational analysis.

The development of the software made extensive use of AI-assisted programming.

I have tested it on real ORCA calculations and, based on my own use and validation so far, I believe the software has the potential to be a useful tool.

At the same time, given my primarily experimental background, I would particularly benefit from the opinion of people with deeper expertise in computational chemistry and vibrational analysis.

Independent testing, criticism and methodological feedback would therefore be extremely valuable.

If you try it and notice:

• incorrect behaviour
• questionable assignments
• methodological limitations
• edge cases
• or simply have suggestions for improving the analysis

I'd be very interested to hear your feedback.

Feedback, criticism, validation cases and contributions are very welcome!

Hi. Here's analysis of 6500K daylight CFL lamps (plus one LED intruder) in infrared by using a stack of 720nm cutoff filter and diffraction filter on a full spectrum converted camera. Fluorescent lamps work through mercury vapor discharge in UV which excites fluorescent phosphors that glow in visible light (plus also mixing directly emitted mercury visible lines). Thing is mercury emission will be only initiated in presence of buffer gas. This may differ between particular types of fluorescent lamps but in case of small self ballasted lamps like it is most often argon. In near-IR region mercury doesn't radiate at all but instead argon radiation can be clearly seen. This overlaps with phosphor emissions. The curious thing is argon most strongly is glowing near electrodes while phosphor emission encompasses whole length of discharge tube so it's possible to separate the two through looking at the shape of spectral image, argon is point dots at bottom while phosphor is elongated shape. There is a >1000nm phosphor emission which surprised me as literature on fluorescent materials used in lamps is sparse in data of infrared emissions. In my opinion it is Yttrium Oxide Y2O3:Eu2+ phosphor which in visible part is the red component but would be happy to get confirmation. Scale was made based on known in literature argon emissions.