Nuclear and Electronic gif (IMAGE) DOE/SLAC National Accelerator Laboratory Caption With previous methods, researchers could watch the nitrogen atom in a pyridine molecule bend up and down when excited by light. With this new method, they were also able to see changes in electron density happening at the same time. Blue bubbles depict decreasing electron density while red show increasing relative to unexcited pyridine. Credit Jimmy Yu/Stanford University Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.