Negative Absorption Peaks in Ultraviolet–Visible Spectrum of Water

Abstract Ultraviolet‐visible absorption spectra exhibit absorption that is under the base line, which we propose is negative absorption (NA) or negative absorption emission (NAE). The UV‐visible NAE of water, ethanol, and chloroform was illustrated by transmittance curves, reflectivity curves, and fluorescence excitation/emission spectra. To explain this phenomenon, the TD_DFT theory was used to calculate the emission states of the samples. A laser transmission experiment confirmed the NAE phenomenon. It was concluded that NAE was a type of emission produced by the sample. The NAE of water has significant implications for life on earth, which will interest researchers in physics, chemistry, and biology.