Research Article Volume 1 Issue 6
Departmnet of Physics, University of M’sila, Algeria
Correspondence: Abdelmadjid Maireche, Laboratory of Physics and Material Chemistry, Department of Physics, Sciences Faculty, University of M’sila, Algeria, Tel +213664834317
Received: August 14, 2018 | Published: November 29, 2018
Citation: Maireche A. A new study of energy levels of hydrogenic atoms and some molecules for new more general exponential screened coulomb potential. Open Acc J Math Theor Phy. 2018;1(6):232-237 DOI: 10.15406/oajmtp.2018.01.00040
In present research paper, the solutions of the modified Schrodinger (MSE) with new more general exponential screened coulomb (NMGESC) potential, have been presented by means generalized Bopp’s shift method and standard perturbation theory, in the noncommutative three dimensional space phase (NC: 3D-RSP). The bound state energy eigenvalues, in terms of the generalized the hypergeometric function, the discreet atomic quantum numbers (j=|l-s|,......(l+s)(n,l)and m),(j=|l−s|,......(l+s)(n,l)andm), two infinitesimal parameters (Θ,χ)(Θ,χ) which are induced by position-position, in addition to, the dimensional parameters of NMGESC potential and the corresponding noncommutative Hamiltonian operator were obtained for hydrogenic atoms and the molecules (CO,NO).(CO,NO). We have also shown that, the total complete degeneracy of energy levels of NMGESC potential equals the new values 2n2.2n2. Furthermore, the global group symmetry (NC: 3D-RSP) corresponding NMGESC potential reduce to the new subgroup (NC: 3D-RS) symmetries.
Keywords: schrödinger equation, hydrogenic atoms, more general exponential screened coulomb potential, noncommutative space and phase, star product and generalized Bopp’s shift method
NMGESC, new more general exponential screened coulomb potential; NC: 3D–RSP, noncommutativity three dimensional real space phase; CCRs, canonical commutations relations; NNCCRs, new noncommutative canonical commutations relations; SP, Schrödinger picture; HP, Heisenberg picture; MSE, modified Schrödinger equation
The more general exponential screened coulomb (MGESC) potential is known to describe adequately the effective potential of a many–body system of a variety of fields such as the atomic, solid state, plasma and quantum field theory.1–4 In particularity, this potential used to calculate the bounded state eigen values of molecules (CO,NO).(CO,NO). The noncommutativity of space–time, which known firstly by Heisenberg and was formalized by Snyder at 1947, suggest by the physical recent results in string theory. Very recently, several authors have attempted to obtain either the exact or approximate solutions of the non–relativistic Schrodinger equation or two relativistic (Klein–Gordon and Dirac) equations for different potentials in NC space. We want to extended, the study of Ita et al.,3 to the case of extended quantum mechanics to the possibility of finding other applications and more profound interpretations in the sub-atomics scales on based to the works5–19 and our previously works20–40 in this context. The no relativistic energy levels for hydrogenic atoms and molecules (CO,NO),(CO,NO), which interacted with NMGESC potential in the context of NC space have not been obtained yet. The purpose of the present paper is to attempt study the MSE with NMGESC potential (see below):
Vmg(r)=−V0r(1+(1+αr)exp(−2αr))→Vmg(ˆr)=V0α−V0ˆr−2V0α3ˆr2Vmg(r)=−V0r(1+(1+αr)exp(−2αr))→Vmg(ˆr)=V0α−V0ˆr−2V0α3ˆr2 (1)
in (NC: 3D-RSP) symmetries using the generalized Bopp’s shift method which depend on the concepts that we present below in the third section. The new structure of extended quantum mechanics based to new NC canonical commutations relations (NNCCRs) in both Schrödinger and Heisenberg pictures ((SP) and (HP)), respectively, as follows (Throughout this paper, the natural units c=ℏ=1c=ℏ=1 will be used):5–23
{[xi,pj]=[xi(t),pj(t)]=iδi j [xi,xj]=[xi(t),xj(t)]=0[pi,pj]=[pi(t),pj(t)]=0 ⇒{[ˆxi∗,ˆpj]=[ˆxi(t)∗,ˆpj(t)]=iδi j [ˆxi∗,ˆxj]=[ˆxi(t)∗,ˆxj(t)]=iθi j [ˆpi∗,ˆpj]= [ˆpi(t)∗,ˆpj(t)]=iˉθi j (2)
However, the new operators ˆξ(t)=[ˆxi(t)∨ˆpi(t)] in (HP) are depending to the corresponding new operators ˆξ=[ˆxi∨ˆpi] in (SP) from the following projections relations:20
ξ(t)=exp(iˆHmg(t−t0))ξexp(−iˆHmgi(t−t0))⇒ˆξ(t)=exp(iˆHn c−n i(t−t0))*ˆξ*exp(−iˆHn c−n i(t−t0)) (3)
Here ξ=(xi∨pi) and ξ(t)=(xi(t)∨pi(t)) , while the dynamics of new systems dξ(t)dt are described from the following motion equations in extended quantum mechanics: 20
dξ(t)dt=[ξ(t),ˆHmg]⇒dˆξ(t)dt=[ˆξ(t)∗,ˆHnc−mg] (4)
the two operators ˆHmg and ˆHnc−mg are presents the ordinary and new quantum Hamiltonian operators for NMGESC potential in the quantum mechanics and it’s extension, respectively, while dˆξ(t)dt are describe the dynamics of systems in (NC: 3D–RSP). The very small two parameters θμν and ˉθμν (compared to the energy) are elements of two anti symmetric real matrixes (θμv,ˉθμv)=−(θvμ,ˉθvμ) and (∗) denote to the new star product, which is generalized between two arbitrary functions (f,g) (x,p)→(ˆf,ˆg)(ˆx,ˆp) to the new form ˆf(ˆx,ˆp)ˆg(ˆx,ˆp)≡(f∗g)(x,p) in ordinary 3-dimensional space-phase:6–21
(f,g) (x,p)→(ˆf,ˆg)(ˆx,ˆp)≡(f∗g)(x,p)=(fg−i2θμν∂xμf ∂xνg−i2ˉθμν∂pμf ∂pνgg)(x,p) (5)
where the notion (∂xμ,∂pμ)f(x,p) denote to the (∂∂pμ,∂∂xμ)f(x,p) . The effects of (space-space) and (phase-phase) noncommutativity properties, respectively induce the second and the third terms in the above equation. The organization scheme of the recently work is given as follows: In next section, we briefly review the ordinary SE with MGESC potential on based to ref.3 The Section 3 is devoted to studying the MSE by applying the generalized Bopp's shift method for NMGESC potential. In the next subsection, by applying standard perturbation theory to find the quantum spectrum of nth excited levels in for spin-orbital interaction in the framework of the global group (NC-3D: RSP) and then, we derive the magnetic spectrum for NMGESC potential. In the fourth section, we resume the global spectrum and corresponding NC Hamiltonian operator for NMGESC potential and corresponding energy levels of hydrogenic atoms and the molecules (CO,NO) . Finally, the concluding remarks have been presented in the last section.
Overview of the eigenfunctions and the energy eigenvalues for MGESC potential for hydrogenic atoms and molecules (CO, NO):
In this section, we shall recall here the time independent SE for a MGESC potential Vmg(r) , which studied by Ita et al.,2 and generalized to new form by Ita et al.,3 also in ref.: 3,4
Vmg(r)=(−ar)(1+(1+b)exp(−2b))→Vmg(r)=−V0r(1+(1+αr)exp(−2αr)) (6)
where a→V0 and b→αr are the strength coupling constant (the potential depth of the MGESC potential) and the screened parameter (adjustable positive parameter), respectively. The part with exp. term of eq. (6) can be expanded in the power series of r up to the second term:
1re−2αr≅1r(1−2αr+2α2r2)=−2α+1r+2α2r (7)
Inserting eq. (7) into eq. (6), explicit form of MGESC potential is obtained as:
V(r)≅V0α−2V0r−2V0α3r2 (8)
If we insert this potential into the Schrödinger equation (3):
(d2dr2+2rddr−l(l+1)r2)Rnl(r)+2μ[Enl+V0r(1+(1+αr)exp(−2αr))]Rnl(r)=0 (9)
Here μ is the reduced mass of molecules (CO,NO) or the reduced mass of electron ant it’s nucleus for hydrogenic atoms. The electronic radial wave functions are shown as a function of the Laguerre polynomial in terms of some parameters:3
Rnl(ν)=Nn,l(2β)12−αexp(−ν2)να−12L2α+1n(ν) (10)
where r=(2β)−1ν , therefore, the complete wave function Ψ(r,θ,ϕ) and the energy Enl of the potential in eq. (6) are given by:3
Ψ(r,θ,ϕ)=Nnl(2β)α−1/2exp(−ν2)να−1/2L2α+1n(ν)Yml(θ,ϕ) (11)and
Enl=−V0e−αr0+2μ(V0+V0e−αr0n+l+1)2 (12)
With r0=1.21282 and r0=1.1508 for (CO and NO) molecules, for hydrogenic atoms, r0 can be present the average dimension between the electron and the nucleus, Nnl is the normalization constant, α=12√4l(l+1)+1 , β2=−2μEnlα2 and Yml(θ,ϕ) are the well-known spherical harmonic functions.
In this section, we shall give an overview or a brief preliminary for a NMGESC potential Vnc-mg(r) , in (NC: 3D-RSP) symmetries. To perform this task the physical form of modified Schrödinger equation (MSE), it is necessary to replace ordinary three-dimensional Hamiltonian operators ˆH(pi,xi) , ordinary complex wave function Ψ(→r) and ordinary energy Enl by new three Hamiltonian operators ˆHnc−mg(ˆpi,ˆxi) , new complex wave function ⌢Ψ(↔⌢r) and new values Enc−mg , respectively. In addition to replace the ordinary old product by new star product (∗) , which allow us to constructing the MSE in (NC-3D: RSP) symmetries as:21–28
ˆHmg(pi,xi)Ψ(→r)=EnlΨ(→r)⇒ˆH(ˆpi,ˆxi)∗Ψ(→ˆr)=Enc−mgΨ(→ˆr) (13)
The Bopp’s shift method employed in the solutions enables us to explore an effective way of obtaining the modified potential in extended quantum mechanics, it based on the following new commutators:28–34
[ˆxi,ˆxj]=[ˆxi(t),ˆxj(t)]=iθij and [ˆpi,ˆpj]=[ˆpi(t),ˆpj(t)]=iˉθij (14)
The new generalized positions and momentum coordinates (ˆxi,ˆpi) in (NC: 3D-RSP) are depended with corresponding usual generalized positions and momentum coordinates (xii,pi) in ordinary quantum mechanics by the following, respectively:30–36
(xi,pi)⇒(ˆxi,ˆpi)=(xi−θij2pj,pi+ˉθij2xj) (15)
The above equation allows us to obtain the two operators ˆr2 and ˆp2 in (NC-3D: RSP):35–38
(r2,p2)⇒(ˆr2,ˆp2)=(r2−→L→Θ , p2+→L→ˉθ )
(16)
The two couplings LΘ and →L→ˉθ are (LxΘ12+LyΘ23+LzΘ13) and (Lxˉθ12+Lyˉθ23+Lzˉθ13) , respectively and (Lx,Ly and Lz) are the three components of angular momentum operator →L while Θij=θij/2 . Thus, the reduced Schrödinger equation (without star product) can be written as:
ˆH(ˆpi,ˆxi)∗Ψ(→ˆr)=Enc−mgΨ(→ˆr)⇒H(ˆpi,ˆxi)ψ(→r)=Enc−mgψ(→r) (17)
the new operator of Hamiltonian Hnc−mgi(ˆpi,ˆxi) can be expressed as:
Hmg(pi,xi)⇒Hnc−mgi(ˆpi,ˆxi)≡H(ˆxi=xi−θij2pj,ˆpi=pi+ˉθij2xj) (18)
Now, we want to find to the NMGESC potential Vmg(ˆr) :
Vmg(r)⇒Vmg(ˆr)=V0α−2V0ˆr−2V0α3ˆr2 (19)
After straightforward calculations, we can obtain the important term (−V0ˆr) , which will be use to determine the NMGESC potential in (NC: 3D- RSP) symmetries as:
−V0r⇒−V0ˆr=−V0r−V0→L→Θ2r3 (20)
By making the substitution above equation into eq. (19), we find the global our working new Hamiltonian operator Hnc-mg(ˆr) satisfies the equation in (NC: 3D-RSP) symmetries:
Hmg(pi,xi)⇒Hnc−mg(ˆr)=Hmg(pi,xi)+(2V0α3−V0r3)→L→Θ+→L→ˉθ2μ (21)
where the operator Hmg(pi,xi) is just the ordinary Hamiltonian operator with MGESC potential in commutative space:
Hmg(pi,xi)=p22μ+V0α−2V0r−2V0α3r2 (22)
while the rest two terms are proportional’s with two infinitesimals parameters (Θ and ˉθ) and then we can considered as a perturbations terms Hper-mg(r) in (NC: 3D-RSP) symmetries as:
Hper-mg(r)=(2V0α3−V0r3)→L→Θ+→L→ˉθ2μ (23)
The exact modified spin-orbital spectrum for NMGESC potential in global (NC: 3D- RSP) symmetries
In this subsection, we apply the same strategy, which we have seen in our previously works,36–40 under such particular choice, one can easily reproduce both couplings (→L→Θ and →L→ˉθ) to the new physical forms ( γ Θ→L→S and γ ˉθ→L→S ), respectively, to obtain the new forms of Hso-mg(r,Θ,ˉθ) for 3D- NMGESC potential as follows:
Hso-mg(r,Θ,ˉθ)≡γ{(2V0α3−V0r3)Θ+ˉθ2μ} →L→S (24)
Here γ≈1137 is a new constant, which play the role of fine structure constant, we have chosen the two vectors →Θ and →ˉθ parallel to the spin →S of hydrogenic atoms. Furthermore, the above perturbative terms Hper-mg(r) can be rewritten to the following new form:
Hso−mg(r,Θ,ˉθ)=γ2{(2V0α3−V0r3)Θ+ˉθ2μ} (→J−→L−→S2) (25)
This operator traduces the coupling between spin →S and orbital momentum →L→S . The set (Hso−mg(r,Θ,ˉθ) , J2,L2,S2 and Jz) forms a complete of conserved physics quantities and for ↔S=→1/2 , the eigen values of the spin orbital coupling operator are k±≡12{(l±12)(l±12+1)+l(l+1)−34} corresponding: j=l+1/2 (spin up) and j=l−1/2 (spin down), respectively then one can form a diagonal (3×3) matrix, with diagonal elements are (Hso−mg)11 , (Hso−mg)22 and (Hso−mg)33 for NMGESC potential in (NC: 3D-RSP) symmetries, as:
(Hso−mg)11=γk+((2V0α3−V02r3)Θ+ˉθ2μ) if j=l+1/2 (Hso−mg)22=γk−((2V0α3−V02r3)Θ+ˉθ2μ) if j=l−1/2 (Hso−mg)33=0 (26)
After profound calculation, one can show that, the new radial function Rnl(r) satisfying the following differential equation for NMGESC potential:
(d2dr2+2rddr−l(l+1)r2)Rnl(r)+2μ[Enl+V0r(1+(1+αr)exp(−2αr))−(2V0α3−V0r3)→L→Θ−→L→ˉθ2μ ]Rnl(r)=0 (27)
The two terms which composed the expression of Hper-mg(r) are proportional with two infinitesimals parameters ( Θ and ˉθ ), thus, in what follows, we proceed to solve the modified radial part of the MSE that is, equation (27) by applying standard perturbation theory for their exact solutions at first order of two parameters Θ and ˉθ .
The exact modified spin-orbital spectrum for NMGESC potential in extended global (NC: 3D- RSP) symmetries
The purpose here is to give a complete prescription for determine the energy level of
nth
excited states, of hydrogenic atoms with NMGESC potential, we first find the corrections
Eu-mg
and
Ed-mg
for hydrogenic atoms which have
j=l+1/2
(spin up) and
j=l−1/2
(spin down), respectively, at first order of two parameters
Θ
and
ˉθ
obtained by applying the standard perturbation theory to find the following:
Eu−mg=γ Nnl2(2β)−2−2αk++∞0exp(−ν)ν2α+1[L2α+1n(ν)]2((2V0α3−V0r3)Θ+ˉθ2μ ) dνEd−mg=γ Nnl2(2β)−2α−2k−+∞0exp(−ν)ν2α+1[L2α+1n(ν)]2((2V0α3−V0r3)Θ+ˉθ2μ ) dν (28)
Now, we can write the above two equations to the new form:
Eu−mg=γ Nnl2(2β)−2α−2k+{ΘT1(n,α)+ΘT2(n,α)+ˉθ2μT3(n,α)}Ed−mg=γ Nnl2(2β)−2α−2k−{ΘT1(n,α)+ΘT2(n,α)+ˉθ2μT3(n,α)} (29)
Moreover, the expressions of the three factors T1(n,α),T2(n,α)and T3(n,α) are given by:
T1(n,α)=2V0α3T3(n,α) =2V0α3+∞0ν(2α+2)−1exp(−ν)[L2α+1n(ν)]2 dν T2(n,α)=−V0(2β)3+∞0ν(2α−1)−1exp(−ν)[L2α+1n(ν)]2 dν (30)
To evaluate the above factors T1(n,α),T2(n,α)and T3(n,α), we apply the following special integration:41
+∞0tε−1..exp(−ωt)Lλm(ωt) Lβn(ωt)dt=ω−εΓ(n−ε+β+1)Γ(m+λ+1)m!n!Γ(1−ε+β)Γ(1+λ)F32(−m,ε,ε−β;−n+ε,λ+1;1) (31)
where F32(−m,ε,ε−β;−n+ε,λ+1;1) is obtained from the generalized hyper geometric function. Fpq(α1,...,αp,β1,....,βq,z) for p=3 and q=2 while Γ(x)=+∞∫0zx−1e−zdz denote to the usual Gamma function. After straightforward calculations, we can obtain the explicitly results:
T1(n,α)=2V0α3T3(n,α)=2V0α3Γ(n)Γ(n+2α+2)n!2Γ(0)Γ(2α+2)F32(−n,2α+2,1;−n+2α+2,2α+2;1)T2(n,α)=−V0(2β)3Γ(n+1)Γ(n+2α+2)n!2Γ(3)Γ(2α+2)F32(−n,2α−1,−2;−n+2α−1,2α+2;1) (32)
We have Γ(0)=(−1)!=∞ , Γ(n+1)=n! and Γ(3)=2 , allow us the two to obtain the exact modifications Eu-mg and Ed-mg of nth excited states of hydrogenic atoms with NMGESC potential, which produced by modified spin-orbital effect Hso−mg(r,Θ,ˉθ) as:
Eu-mg=−12γ ΘNnl2(2β)1−2αV0k−f(n,α)Ed-mg=−12γ ΘNnl2(2β)1−2αV0k+f(n,α) (33)
Where f(n,α) is given by:
f(n,α)=Γ(n+2α+2)n!Γ(2α+2)F32(−n,2α−1,−2;−n+2α−1,2α+2;1) (34)
Thus, the extended global quantum group symmetry (NC: 3D-RSP) reduce to new quantum subgroup symmetry (NC: 3D-RS).
The exact modified magnetic spectrum for NMGESC potential in extended global (NC: 3D- RSP) symmetries:
Further to the important previously obtained results, now, we consider another physically meaningful phenomena produced by the effect of NMGESC potential related to the influence of an external uniform magnetic field
→B
, to avoid the repetition in the theoretical calculations, it’s sufficient to apply the following replacements:
{→Θ→χ→B→ˉθ→ˉσ→B⇒((2V0α3−V02r3)Θ+ˉθ2μ)⇒((2V0α3−V02r3)χ+ˉσ2μ)→B→L (35)
Here χ and ˉσ are two infinitesimal real proportional’s constants, and we choose the arbitrary external magnetic field →B parallel to the (Oz) axis, which allow us to introduce the new modified magnetic Hamiltonian Hm−mg in (NC: 3D-RSP) symmetries as:
Hm−mg=((2V0α3−V02r3)χ+ˉσ2μ)ℵmod−z (36)
Here ℵmod−z≡→B→J−ℵz denote to the modified Zeeman effect while ℵz≡−→S→B is the ordinary Hamiltonian operator of Zeeman Effect. To obtain the exact noncommutative magnetic modifications of energy Emag-mg(n,m,α) , we just replace k+ and Θ in the eq. (33) by the following parameters: m and χ , respectively:
Emag−mg(n,m,α)=−12γ χNnl2(2β)1−2αV0k−f(n,α)Bm (37)
We have −l≤m≤+l , which allow us to fixing ( 2l+1 ) values for discreet number m .
In the light of the results of the preceding sections, let us resume the modified eigenenergies Enc -umg(n,j,l,s,m,α) and Enc -dmg(n,j,l,s,m,α) of a hydrogenic atoms with spin →S=→1/2 for MSE with NMGESC potential obtained in this paper, the total energies corresponding nth excited states in (NC: 3D-RSP) symmetries are determined on based to our original results presented on the Eqs. (33) and (37), in addition to the ordinary energy Enl MGESC potential, which presented in the eq. (13):
Enc -umg(n,j,l,s,m,α)=Enl−12χ γNnl2(2β)1−2αV0k+f(n,α)(Θk++Bmχ)Enc -dmg(n,j,l,s,m,α)=Enl−12χ γNnl2(2β)1−2αV0k−f(n,α)(Θk−+Bmχ) (38)
This is the main goal of this work, It’s clearly, that the obtained eigenvalues of energies are real’s and then the noncommutative diagonal Hamiltonian Hnc−mg is Hermitian, furthermore it’s possible to writing the three elements: α as follows:
(Hnc−mg)11=−Δnc2μ+Hint−umg(Hnc−mg)22=−Δnc2μ+Hint−dmg(Hnc−mg)33=−Δ2μ−V0r(1+(1+αr)exp(−2αr)) (39)
Where
Δnc2μ=Δ−ˉθ→L−ˉσ→L2μHint−umg=−V0r(1+(1+αr)exp(−2αr)) +γ(k+Θ+χ ℵmod−z)(2V0α3−V0r3)Hint−dmg−V0r(1+(1+αr)exp(−2αr)) +γ(k−Θ+χ ℵmod−z)(2V0α3−V0r3) (40)
Thus, the ordinary kinetic term for MGESC potential −Δ2μ and ordinary interaction −V0r(1+(1+αr)exp(−2αr)) >are replaced by new modified form of kinetic term Δnc2μ and new modified interactions modified to the new form ( Hint−umg and Hint−dmg ). On the other hand, it is evident to consider the quantum number m takes (2l+1) values and we have also two values for j=l±12 , thus every state in usually three dimensional space of energy for NMGESC potential will be 2(2l+1) sub-states. To obtain the total complete degeneracy of energy level of the NMGESC potential in noncommutative three-dimension spaces-phases, we need to sum for all allowed values of l . Total degeneracy is thus,
2n−1∑i=0(2l+1)≡2n2 (41)
Note that the obtained new energy eigen values (Enc -umg(n,j,l,s,m,α)and Enc-dmg(n,j,l,s,m,α)) and Enc -mg(n,j,l,s,α,m) now depend to new discrete atomic quantum numbers (n,j,l,s)and m in addition to the parameter α of the potential. It is pertinent to note that when the molecules (CO,NO) have →S≠→1/2 , the total operator can be obtains from the interval |l−s|≤j≤|l+s| , which allow us to obtaining the eigenvalues of the operator (↔J2−↔L2−↔S2) as k(j,l,s)≡j(j+1)+l(l+1)−s(s+1) and then the non-relativistic energy spectrum Enc -mg(n,j,l,s,m,α) reads:
Enc -mg(n,j,l,s,m,α)=−V0e−αr0+2μ(V0+V0e−αr0n+l+1)2−12γ χNn l2(2β)1−2αV0f(n,α)(Θ k(j,l,s)+Bmχ) (42)
Paying attention to the behavior of the spectrums (38) and (42) (Enc -umg(n,j,l,s,m,α)and Enc -dmg(n,j,l,s,m,α)) , it is possible to recover the results of commutative space (12) when we consider (Θ,χ)→(0,0) . Finlay, we can say that the results we have obtained in our recently research are more profound than the results listed in our reference.20
In this paper three-dimensional MSES for NMGESC potential has been solved via Bopp’s shift method and standard perturbation theory in (NC: 3D-RSP) symmetries, we resume the main obtained results:
None.
Author declares that there is no conflicts of interest.
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