Effect of plasma environment on spectral and structural properties of H-like C, N and O ions

•Energy levels and transition properties are studied for H-like C, N and O ions under the influence of dense plasma.•Eigen state, probability and average position are calculated with plasma concentration.•Radial probability density and classical position of H-like ions are studied.•Plasma shift of H-like ions are studied graphically as a function of plasma concentration.•Oscillator strengths of H-like ions are studied for dipole allowed transitions. The novel studies of the dense plasma on transition properties and level structures for H-like Carbon, Nitrogen and Oxygen ions are presented. Plasma effect is included through the confined ion sphere plasma model. We have also included relativistic effects through mass-correction, Darwin and spin-orbit terms during the calculation. The energy level shift, oscillator strengths, transition rates, plasma shifts and probability densities are calculated by using Ritz’s variation method for different ion sphere plasma concentrations. The variation parameters are calculated by minimizing the expectation value of the energy. Eigenstate, probability and average position are calculated with plasma concentration for the internal structure of the system. We have compared our calculated data with experimental National Institute of Science and Technology (NIST) database and other theoretical results in the literature and it is showing a good quantitative agreement. The study may be very useful in astrophysical and fusion plasma.