<html><body><div style="color:#000; background-color:#fff; font-family:times new roman, new york, times, serif;font-size:12pt"><div>I actually performed non-relativistic calculations earlier for 7BeO case. However I think very close to the nucleus, relativistic effects are important even for beryllium. I performed non-relativistic calculations for different values of <span class="Apple-style-span" style="border-collapse: separate; ">R0 (R0=0.0001 BU, 0.00001 BU, 0.00004 BU) and found that the value of the electron density becomes somewhat different from the relativistic calculation at the same R0. For different values of R0, the electron density changes as expected for non-relativistic calculation also. However the rate of change (K_P) of the fractional electron density (Delta_Lambda/Lambda) with the external pressure remains the same whether relativistic or non-relativistic calculation is done and is also independent of R0. </span></div><div
style="color: rgb(0, 0, 0); font-size: 16px; font-family: 'times new roman', 'new york', times, serif; background-color: transparent; font-style: normal; "><span class="Apple-style-span" style="border-collapse: separate; "><br></span></div><div style="color: rgb(0, 0, 0); font-size: 16px; font-family: 'times new roman', 'new york', times, serif; background-color: transparent; font-style: normal; "><span class="Apple-style-span" style="border-collapse: separate; ">I think for a finite nucleus, the result should be different, because the character of the wave function (both radial and Z-dependence) should change and I think calculated K_P will increase. I also think that for calculating the electron density at the nucleus, relativistic effects are important, even for a light nucleus. </span></div><div style="color: rgb(0, 0, 0); font-size: 16px; font-family: 'times new roman', 'new york', times, serif; background-color: transparent; font-style:
normal; "><span class="Apple-style-span" style="border-collapse: separate; "><br></span></div><div style="color: rgb(0, 0, 0); font-size: 16px; font-family: 'times new roman', 'new york', times, serif; background-color: transparent; font-style: normal; "><span class="Apple-style-span" style="border-collapse: separate; ">With best regards</span></div><div style="color: rgb(0, 0, 0); font-size: 16px; font-family: 'times new roman', 'new york', times, serif; background-color: transparent; font-style: normal; "><span class="Apple-style-span" style="border-collapse: separate; ">Amlan Ray</span></div><div style="color: rgb(0, 0, 0); font-size: 16px; font-family: 'times new roman', 'new york', times, serif; background-color: transparent; font-style: normal; "><span class="Apple-style-span" style="border-collapse: separate; ">VECC, Kolkata, India</span></div></div></body></html>