Recent content by sandf

Dear all, I am sorry if the topic is not appropriate in this subForum. As a chemist, I am confused by the expression of "first principle, first principles, first-principles, and first-principle calculaltion". In chemistry, we only use "ab-initio". Best regards. Youzhao Lan Department of...

Dr.Du, thanks for your help. Lan

I have a set of k-points, e.g. k1,k2,k3,k4. and they are equivalent by symmetry. Now I have calculated the momentum matrix element <i|p|j> at k1 point ONLY, and then calculate the optical properties which, for example, depend on <i|p|j><j|p|i> I have to make a summation on four k-points...

Dear DrDu, Thank you very much! The infinite summation seems to be another difficult task for obtaining exact results. Best regards. Lan

Thank you very much, I get it. Best regards. Lan

Dear all, I want to directly calculate the polarizability using the following perturbation expression, when the ground state wave function |0> is known. for example, for He atom, r1 and r2 two electrons. ##\alpha = \frac{2}{3}\left\langle {0|({r_1} + {r_2})\frac{1}{{H - {E_0}}}({r_1} +...

Dear Bernhardt, Thanks for your attention. I also ask for help on the forum of DALTON program which implements the CCSD response calculation for TPA. Unfortunately, I haven't gotten the response. Bests Lan

Dear all, I have calculated the rotationally averaged two-photon transition strength (DeltaTPA) using the CCSD response approach. Degenerate TPAs of ten excited states have been calculated. For most of the excited states considered, I got the positive DeltaTPAs, while for some excited states...

Dear Bandersnatch, Great thanks for your help. Best regards. sandf

Dear Bandersnatch, Thanks for your help. Is it also assumed that only a single photon can be absorbed? Otherwise, could I have the equation. nh\nu=E_k+W, which also means the emisstion of a single photon. Best sandf

Dear lawmaker, Thanks for your reply. But I cannot understand what you mean. In terms of your opinion, may I create the energy conservation equation n1hv1 = 1/2mv2+W+n2hv2 ? I understand the photoelectric effect that this phenomenon cannot occur when the energy of one photon is not...

If I write photoelectric effect equation to nhv = 1/2mv2 + W with n = 1, I am puzzled whether the n is larger than 1, such as 2 or 3, for which I will get the two- or three- photon absorption. Could you give me some comments on these question? Best regards. sandf

Homework Statement Two-electron Wavefunction: ψ(r1,r2,r12) = exp(-Ar1-Br2-Cr12), r12 = |r1-r2| A, B, and C are coefficients Calculate <ψ|δ(r12)|ψ> and <ψ|δ(r1)|ψ> Homework Equations NO The Attempt at a Solution <ψ|δ(r12)|ψ> = ∫∫dv1dv2ψ2(r1,r2,r12)δ(r12)...

Dear Solkar, I try to reproduce it. It possibly has something to do with the use of 'parameter'. not 'allocatable' But even if I do not use "parameter", and N<100, the program will also work fine. I reproduce under the Intel.Visual.Fortran.Compiler.v11 (Evaluation from intel) and MS...

Dear Solkar, Thanks for your try. I have not customized the LAPACK CMake-build by any means. Windows version LAPACK, I downloaded it from http://icl.cs.utk.edu/lapack-for-windows/lapack/ based on CMake build. Stack overflow indeed puzzles me. Please let it alone. Main issue is that...