Using the semiclassical perturbation method , electron- , proton- , and ionized helium-impact line widths and shifts for the nine Cr i spectral lines from the 4 p ^ { 7 } P ^ { 0 } -4 d ^ { 7 } D multiplet , have been calculated for a perturbers density of 10 ^ { 14 } cm ^ { -3 } and temperatures T = 2,500 - 50,000 K. The obtained results have been used to investigate the influence of Stark broadening effect in the Cr-rich Ap star \beta CrB atmosphere on line shapes of these lines .
It has been found that the contribution of the proton and He ii collisions to the line width and shift is significant , and it is comparable and sometimes ( depending of the electron temperature ) even larger than electron-impact contribution .
Moreover , not only the Stark line width , but , depending on the electron- , proton- , and He ii density in stellar atmosphere also the Stark shift may contribute to the blue as well as to the red asymmetry of the same line .
The obtained results have been used to investigate the influence of Stark broadening effect on line shapes of Cr i lines in the atmosphere of Cr-rich Ap star \beta CrB .